How to Conduct a Sanitary
Survey of Small Water
Systems
A Learner's Guide
Designed to Assist in the Delivery of a Sanitary
Survey Training Course
2003 Edition
-------
Office of Water (4606)
EPA816-R-03-012
www.epa.gov
April 2003
-------
Contents
Introduction 1-1
Learning Objectives ..1-1
Course Description i-1
Entering Competencies of Participants I-3
Definition of Sanitary Survey I-3
Rationale for Conducting Sanitary Surveys I-3
Personnel to Conduct Survey I-3
1 Organizing the Sanitary Survey 1-1
Learning Objectives 1-1
Preparation 1-1
Regulations and Standards to Consider 1-2
Contacts 1-2
Organizing Equipment 1-3
General Recommendations for On-site Inspections 1-3
Communications During the On-site Visit 1-4
Sequence of Activities , 1-4
Follow-up 1-6
The Sanitary Survey Report 1-6
Corrective Action 1-7
2 Drinking Water Regulations 2-1
Learning Objectives 2-1
Data Collection 2-1
Regulations and Standards to Consider 2-2
Drinking Water Regulations 2-2
Sanitary Surveys and the Regulations 2-4
Sanitary Surveys and Capacity Development 2-12
3 Water Sources 3-1
Learning Objectives 3-1
Data Collection 3-1
Regulations and Standards to Consider 3-1
Water Sources 3-2
Sanitary Deficiencies - Quantity 3-2
-------
How to Conduct a Sanitary Survey
Quality of Water 3-3
Sanitary Deficiencies - Quality 3-5
Source Protection 3-5
Sanitary Deficiencies - Source Protection 3-6
Wells - Specific Sanitary Deficiencies 3-7
Sanitary Deficiencies Related to Wells 3-8
Surface Sources - Sanitary Deficiencies 3-12
Streams and Rivers 3-12
Infiltration Galleries 3-13
Sanitary Deficiencies Related to Surface Sources 3-14
Springs - Specific Sanitary Deficiencies 3-15
Sanitary Deficiencies Related to Springs 3-16
Roof Catchments 3-17
Sanitary Deficiencies Related to Roof Catchments 3-18
Transmission - Specific Sanitary Deficiencies 3-19
Sanitary Deficiencies - Transmission System 3-19
4 Water Supply Pumps and Pumping Facilities 4-1
Learning Objectives 4-1
Data Collection 4-1
Regulations and Standards to Consider 4-1
Water Supply Pumps and Pumping Facilities 4-1
Sanitary Deficiencies for the Pumping Station and Well House 4-3
Sanitary Deficiencies for Pumping Equipment and Appurtenances 4-5
Sanitary Deficiencies - Auxiliary Power 4-11
Sanitary Deficiencies - Operation and Maintenance 4-13
5 Storage Facilities 5-1
Learning Objectives 5-1
Data Collection 5-1
Regulations and Standards to Consider 5-1
Storage Facilities 5-2
Direct Contamination Concerns 5-6
Basic Information - Hydropneurnatic Tanks 5-9
6 Water Treatment Processes 6-1
Learning Objectives 6-1
Data Collection 6-1
Regulations and Standards to Consider 6-2
Water Treatment Processes 6-2
Operation and Maintenance of Chemical Feed 6-3
Sanitary Deficiencies - Chemical Feed Systems 6-5
Treatment Processes 6-7
Sanitary Deficiencies - Disinfection Dosages and Residuals 6-9
Hypochlorination Systems 6-11
Sanitary Deficiency - Hypochlorination Systems 6-11
Gas Chlorination Systems 6-12
Sanitary Deficiencies - Gas Chlorination Systems 6-13
iv
-------
Contents
Turbidity Removal 6-16
Sanitary Deficiencies - Conventional Treatment 6-18
Organics Removal 6-30
7 Distribution Systems 7-1
Learning Objectives 7-1
Data Collection 7-2
Regulations and Standards to Consider 7-2
Distribution Systems 7-2
Sanitary Deficiencies for Distribution Systems 7-5
8 Cross-Connections 8-1
Learning Objectives 8-1
Data Collection 8-1
Regulations and Standards to Consider 8-1
Cross-Connections ...8-2
Sanitary Deficiencies and Cross-Connections 8-9
9 Monitoring and Laboratory Testing 9-1
Learning Objectives 9-1
Data Collection 9-1
Regulations and Standards to Consider 9-1
Monitoring and Laboratory Testing 9-2
10 Utility Management 10-1
Learning Objectives 10-1
Data Collection 10-1
Utility Management 10-1
Organization 10-3
Personnel 10-5
Operations 10-6
Finance 10-7
Appendix A A-1
Suggested References A-1
-------
-------
Introduction
A sound sanitary survey program is an essential
element of an effective state drinking water
program. Sanitary surveys fundamental to helping
the state drinking water program better understand
how a system is operating and ensure that the
water system is providing safe water and
protecting public health.
Learning Objectives
By the end of this chapter, learners should be able:
To evaluate their own background and
experiences and identify subjects to learn
more about during the training.
To define "sanitary survey" and explain the
purpose of a sanitary survey of a small
water system.
To explain that the focus of the training is
the identification of conditions or
deficiencies that may cause public health
risks in a typical small water system.
Course Description
Purpose of this Training Guide
This sanitary survey training course is designed for
field staff who inspect and evaluate small water
systems for sanitary deficiencies and compliance
with the Safe Drinking Water Act (SDWA). Its
purpose is to apply basic scientific information and
a working knowledge of the operation,
maintenance, management, and technology of a
small water system to identify sanitary
deficiencies. Sanitary deficiencies are defects in a
water system's infrastructure, design, operation,
maintenance, or management that cause, or may
"Using need-to-know criteria and
delivered by professional technical
instructors, a competency based
training course is a training approach
to bringing and maintaining nationwide
consistency in the conduct of a
sanitary survey of a small water
system."
Ken Hay, EPA Educational Specialist.
cause, interruptions to the "multiple barrier"
protection system and adversely affect the system's
ability to produce, reliably and in adequate
quantities, safe drinking water. Most community
water systems must correct sanitary deficiencies
determined to be "significant deficiencies."
Need-to-Know Criteria
The training is designed to present the activities of
a sanitary survey and identify the questions to ask
and the conditions to look for. This Guide
addresses each of the eight elements of a sanitary
survey as defined in the EPA/State Joint Guidance
on Sanitary Surveys, December 1995. (A separate
chapter covers cross-connections because they are
of concern in both treatment and distribution
systems.) In addition, the training discusses the
process for conducting a sanitary survey;
familiarizes the learner with security concerns;
reviews applicable federal drinking water
regulations; and explains the relationship between
federal and state regulations. The chapters of this
Guide, and the activities the learner will be able to
do after working through them, are presented
below.
1-1
-------
How to Conduct a Sanitary Survey
Organizing the Sanitary Survey - Prepare
for, conduct, and perform follow-up
activities for a sanitary survey.
Regulations - Explain the applicability of
federal regulations that apply to water
systems and their relationship to state
regulations.
Water Sources - Evaluate water supply
sources and intake structure to determine
proper source protection.
Storage Facilities - Evaluate the adequacy,
reliability, and safety of finished water
storage.
Treatment Processes - Evaluate treatment
processes, facilities, components, and
techniques and related chemical addition and
handling.
Distribution System - Evaluate the
adequacy, reliability, and safety of the
system for distributing water to consumers.
Cross-Connections - Identify
cross-connections and evaluate the
cross-connection control program.
Pumps and Pumping Facilities - Identify
proper operation and maintenance of water
system pumps and pumping facilities.
Monitoring, Reporting and Data
Verification - Review monitoring data for
source and finished water quality for
bacteriological, physical, chemical and
radiological properties and, as required,
perform and evaluate results of field
analyses.
Management - Evaluate the effect of
management practices on the reliability of
the system and review the qualifications of
system personnel.
Length of Training
This basic training lasts 3 1/2 days and focuses on
the information an inspector needs to know in order
to recognize and identify conditions or practices
that may contribute to a sanitary risk. The training
can also be taught as a 2-day session focusing
either on sanitary surveys of ground water systems
or surface water systems. It can also be adapted to
address state-specific needs such as a state's
standard sanitary survey form and significant
deficiencies, or sanitary surveys of non-community
systems. In each case the training presents the
opportunity to discuss what sanitary deficiencies
are, where they are most likely to occur, and how
to recognize or anticipate them.
Approach
The training combines classroom presentations and
discussion with site visits to ground water and
surface water systems. The field exercises
conducted during the site visits provide
opportunities for hands-on application of
classroom information to identify actual
problematic conditions (i.e., sanitary deficiencies)
that may contribute to a public health or "sanitary"
risk. Guided team discussions after the field
exercise clarify the reasons the deficiencies present
public health risks and identify potential corrective
actions that might be taken to eliminate the risks.
Field Exercise
Participants are divided into teams and conduct a
sanitary survey during the on-site field exercises.
Summaries of team findings are presented for
discussion by participants. Participants should be
punctual and dress appropriately for field exercises
and for possible inclement weather.
Training Materials
Instruction is supplemented with this Learners
Guide, two Field Guides (ground water and surface
water), and audiovisual training materials. Unless
otherwise noted, the standards and rates mentioned
throughout the guide have been taken from the
publications "Technologies for Upgrading Existing
or Designing New Drinking Water Treatment
Facilities," U.S. EPA Office of Drinking Water
Center for Research Information, Cincinnati, OH
45268 (EPA/625 4-89/023) and "Recommended
Standards for Water Works," 1997, Health
Education Services, Health Research Inc., P.O.
U^^TIOA AIKo,,,, MVlTJ)1/1f^10\/na'7OQA A
1JU/V 1 L <^\J, J-11UCU1J, 1 * . A . I ~^^-r vi^iu/-r^^-/^v^vv. j i
list of additional references is provided in the
appendices along with a list of training films and
video tapes.
1-2
-------
Introduction
Entering Competencies of
Participants
Essential Background
Participants who have a working knowledge of the
vocabulary associated with water systems and an
understanding of how water systems work will
benefit from the competency-based sanitary survey
training. Basic knowledge of small water systems
is essential. Participants will be encouraged to
interact with one another, share experiences and
case histories, enter into team exercises and
discussions, ask questions, and contribute answers
and solutions to problems as they are presented.
Definition of Sanitary Survey
Definition
A sanitary survey is defined in 40 CFR 141.2 as
"an on-site review of the water source (identifying
sources of contamination using results of source
water assessments where available), facilities,
equipment, operation, and maintenance and
monitoring compliance of a public water system for
the purpose of evaluating the adequacy of such
sources, facilities, equipment, operation, and
maintenance for producing and distributing safe
drinking water." In addition, an assessment of
management practices is included in this Guide.
Classes of Surveys
Sanitary surveys may be Class I or Class II:
A Class I sanitary survey is a
comprehensive on-site evaluation of all
water system components and operation and
maintenance procedures. The state should
conduct Class I sanitary surveys for all
community water systems no less frequently
than once every three years and for non-
community systems at least once every five
years. All Class I sanitary surveys should
address sources; treatment; distribution;
finished water storage; pumping facilities
and controls; monitoring, reporting, and
data verification; system management and
operation; and operator compliance with
state requirements.
A Class II sanitary survey is a limited
on-site survey, conducted on an as-needed
basis. The survey may include, but is not
limited to, specific water system component
inspections, operations and maintenance
procedure inspections, investigatory
(complaint-related) inspections. Class I
follow-up inspections, or inspections
conducted as a result of a compliance
problem and/or enforcement related action.
A Class II Survey is not a substitute for a
Class I Survey.
Rationale for Conducting Sanitary
Surveys
Compliance Driven
The sanitary survey is compliance driven. The
SDWA regulations are designed to prevent the
development of conditions and practices that
contribute to sanitary deficiencies. The National
Primary Drinking Water Regulations (40 CFR Part
141) require that sanitary surveys be conducted at
public water systems at least every 3 to 5 years,
depending on the type of system and size.
Consequently, compliance is a very good indication
of a system's ability to reliably produce an
adequate supply of safe drinking water. The
sanitary survey inspector should be concerned
whether long-term compliance is likely, or whether
compliance is precarious and possibly subject to a
high degree of risk that could impair water quality
or quantity and jeopardize public health.
Personnel to Conduct Survey
Who Conducts Sanitary Surveys
Sanitary surveys must be conducted by competent
personnel who have experience and knowledge of
the design, operation, maintenance, and
management of small water systems. These
individuals must be qualified to assess problems
and make sound decisions using hydrological,
hydraulic, mechanical, and other basic engineering
and management knowledge.
1-3
-------
Organizing the
Sanitary Survey
To conduct an effective and efficient sanitary
survey, the inspector must organize and plan the
entire effort. Many critical steps are required,
beginning with the first phone call to arrange the
on-site inspection and ending with the sustainable
correction of sanitary defects. The sanitary survey
process has three stages:
Preparation, including background research.
On-site inspection.
Follow-up activities to ensure that sanitary
deficiencies are corrected
The sanitary survey process should be viewed as a
cooperative partnership between the primacy
agency and the water purveyor since both share the
goal of providing safe drinking water to the public.
To plan a schedule for the sanitary survey,
estimating the time required for each
activity.
To evaluate sample forms and discuss field
notes as tools to assist in conducting the
survey.
To identify personal protective equipment
and safety precautions for inspectors during
an on-site inspection.
To identify field test equipment for
inspectors, and explain the importance of a
preventive maintenance program for field
equipment.
To explain the functions of a sanitary survey
report and technical assistance.
Learning Objectives
By the end of this chapter, learners should be able:
To give an overview of activities that occur
before, during, and after a sanitary survey of
a small water system.
To determine with whom to communicate
and how to communicate before, during, and
after an on-site inspection.
To identify a purpose for speaking with each
of the contacts identified. Explain what
types of information should be
communicated and in what form.
To explain the activities to be accomplished
during the preparation phase and the
importance of each activity.
Preparation
Planning
Estimate Time Required. In planning the sanitary
survey, the inspector needs to estimate the time
required in order to manage his time well. The
estimate should include time prior to, during, and
after the on-site inspection. Although the time
required will vary with the complexity of the water
system and the experience of the inspector, a good
rule of thumb is 2 hours in the office for every hour
in the field.
Research
Review Files. Prior to each survey, the inspector
should review available information for at least the
past 5 years concerning the system to be surveyed.
The review will help the inspector to become fully
briefed on the system's history and condition.
1-1
-------
How to Conduct a Sanitary Survey
Often, if the inspector is familiar with the system's
history, it is easier to understand remarks made
during the on-site inspection concerning previous
letters or conversations that may otherwise be
taken out of context, misstated, or misunderstood.
Knowledge of the system's past conveys to the
water system personnel the inspector's
professionalism and concern for the system. The
end result will be better, more accurate, and useful
information concerning the operation and facilities.
The inspector should obtain as much of the
following information about the water system as
possible before the sanitary survey inspection. This
information should be available from the primacy
agency's electronic database and hard-copy files.
Otherwise, the information and data may be
obtained during the inspection.
Prior sanitary survey reports.
Correspondence with the state.
Compliance monitoring results.
The system's consumer confidence report.
Records of enforcement actions or warnings
of potential actions.
Plans on file (e.g., source protection,
monitoring, emergency or contingency plans,
cross-connection control, capital
improvement).
Minimum operator certification
requirements.
Contacts
Phone and Write
The inspector must contact the water system owner
to explain the purpose of the sanitary survey;
schedule a meeting location, date, and time when
key personnel will be available; and discuss any
preparations the water system staff need to make
for the sanitary survey.
Telephone contact followed by a short follow-up
notification letter is recommended. The letter
should reiterate the content of the phone
conversation. It should also provide instructions for
requesting changes to the schedule. This is also a
good opportunity to emphasize the reasons for
performing the survey and to inform water system
personnel of specific information they will need to
provide. This contact should give system personnel
sufficient time to respond to the notice.
It is essential that the inspector contact the person
directly responsible for the overall management of
the system (e.g., CEO, mayor, water commissioner,
utility manager) in order to obtain cooperation,
gather information, coordinate with other
departments or agencies, and transmit the results of
the evaluation. Prior to the on-site inspection, the
inspector should contact the people identified in the
table below.
Regulations and Standards to
Consider
The inspector should also review and consider the
following materials prior to the inspection:
40 CFR Part 141 - National Primary
Drinking Water Regulations, as adopted by
the state.
Additional state regulations.
State engineering and construction
standards.
EPA's proposed ground water rule.
Capacity development guidance.
Contact Purpose
Water System Obtain cooperation
Owner Establish survey dates
Explain purpose of survey
Request that necessary
information be available
Coordinate gaining entry to site
Ensure presence of all
necessary operational
personnel during survey
Other « Ensure cooperation and
Regulatory coordination
Agencies Obtain information pertinent to
system
1-2
-------
Chapter 1 - Organizing the Sanitary Survey
Changing the Schedule. If the schedule must be
changed, the inspector should change it as early as
possible. The survey must never be postponed or
canceled without prior notification of the water
system's representatives.
Organizing Equipment
Field Test Equipment
Check Your Equipment. Prior to the on-site
inspection, sanitary survey inspectors should
ensure that field equipment is in good repair.
Preventive maintenance is essential for all types of
equipment. Equipment that is broken, dirty, in
disrepair, out of calibration, or otherwise
improperly maintained will not provide accurate,
dependable, or reproducible data. For best results,
follow the manufacturer's specifications for
preventive maintenance.
Check Standards. Of equal importance are
standards for the field test equipment. The
inspector should check expiration dates and keep
up with and use current standard testing methods
and calibration procedures.
Recommended Equipment. Recommended types
of field test equipment include, but are not limited
to, the following:
Portable pH meter (digital, not analog).
Residual chlorine test kit (hand held
colorimeter or portable spectrophotometer).
Camera with automatic time stamp.
Binoculars.
Flashlight.
Personal Protective Equipment and
Safety Precautions
Inspector Safety. Another aspect of the sanitary
survey is safety. This is a concern for the field
inspector as well as for the operating staff of the
system. Safety hazards include:
Electrical shock
Exposure to chemicals
Drowning
Entering confined spaces
High-intensity noise
Sprains and strains due to lifting
Slips, trips, and falls
Safety Equipment. Prior to the on-site inspection,
the sanitary survey inspector should ensure that
personal protective equipment is available. We
acknowledge that many state agencies do not
provide this equipment, however, the inspector may
wish to provide some of the equipment and ensure
that items such as respirators are available at the
site. The most frequently used equipment and the
necessity of each is as follows:
Safety hats - Provide protection from
falling objects and overhead obstructions in
pipe galleries. They can also be used as a
means of identification.
Goggles - Provide eye protection from
chemicals and flying objects. They may need
to be supplemented by full face shield when
working around some chemicals.
Gloves - Provide protection against injuries
from chemicals and equipment. Rubberized
materials are preferred over leather or cloth
gloves.
Steel-toed safety shoes - Provide protection
from falling objects.
Respirators - Protect the wearer from
inhaling dust, Hanta virus, organic vapors,
and other chemicals. This equipment is used
where the atmosphere is not
oxygen-deficient.
Self-contained breathing apparatus -
Provides protection in oxygen-deficient
atmospheres (e.g., confined spaces).
General Recommendations for
On-site Inspections
Keep Purpose in Mind
In conducting the on-site inspection, it is
important for the inspector to remember the
purpose of the survey. The inspector is to perform
an on-site review of the water source, facilities,
equipment, operation, maintenance, and
1-3
-------
How to Conduct a Sanitary Survey
management for the production and distribution of
safe drinking water. The inspector should not let
the sanitary survey become an exercise in
filling in the blanks on a particular form. An
inspector needs to concentrate on identifying
potential or existing problems and evaluating their
risks.
Be Punctual - Work With the Water
System Staff
In performing the on-site survey, the first step is to
be punctual so that system personnel are not
waiting for the inspector. A successful survey
requires representatives of the water system to
participate in the sanitary survey process.
Individuals in charge of management, operation,
and maintenance should be involved during the
on-site inspection. Besides providing the inspector
with critical information, this will allow the
inspector and staff members to interact and develop
a mutual understanding of the purpose of the
survey and confidence in each other's abilities.
Once this trust has been developed, the staff may
be more willing to be open about the operations
and problems of the system.
Use Forms and Field Notes
Field notes, diagrams, and completed inspection
forms are critical to the sanitary survey process. A
properly designed form can facilitate and simplify
the conduct of the sanitary survey. A field
inspection form is a data management tool. It can
serve as a systematic guide during the survey and
ensure completeness so that critical data or other
information are not overlooked. A good form
anticipates questions and affords the inspector the
opportunity to focus on answers and responses and
to record observations without the distraction of
planning the next question.
In most cases, it is good to use a standard form to
help the inspector cover all points of the system. It
is important to remember that filling out a form
is not the primary function of the survey. The
inspector should understand why each question is
being asked. The judicious use of the form,
however, will provide uniformity of inspections,
ensure completeness of the inspection, facilitate
recordkeeping, document observations, and allow
follow-up inspection by another inspector.
Communications During the
On-site Visit
Contacts During the Survey
During the inspection, the inspector should work
with the owner of the water system and the
operational personnel.
When meeting with the system owner, the inspector
should:
Obtain information pertinent to system
Explain use of survey results
Explain recommended actions
Explain what action will result from survey
When communicating with the operational
personnel, the inspector should:
Obtain information pertinent to system
Explain recommended action
Relationship with Operator
Establishing a good relationship with the
operational personnel is important to the success of
the survey. The operator of the small water system
occupies a unique position in the water supply
industry. In most cases, the operator is responsible
for all aspects of the system from operation of the
plant to budgeting for equipment. In small systems,
he may also be responsible for other services in the
community (e.g., wastewater treatment, road
repair). Consequently, the operator may have a
basic working knowledge of his water system and
processes, but not necessarily knowledge of the
regulatory requirements.
Sequence of Activities
The on-site inspection should be carried out in a
systematic fashion. The sequence should include
the following steps:
Initial briefing
Background review
Management assessment
Facility walk-through
Inspector's assimilation of findings
Debriefing
The details of each activity follow.
1-4
-------
Chapter 1 - Organizing the Sanitary Survey
Initial Briefing
The purpose of the initial briefing with water
system personnel is to explain the purpose of the
sanitary survey and describe the sequence of
activities to be completed during the on-site
inspection. This is also an opportunity for the
inspector and water system personnel to discuss
concerns that are not directly related to the
inspection (e.g., proposed regulations or activities
of the primacy agency). Management, operations,
and maintenance staff should be represented at this
briefing.
Background Review
This session also involves personnel representing
management, operations, and maintenance of the
water system. During this phase, the inspector
should review previous sanitary survey reports and
discuss actions taken by the water system on any
sanitary deficiencies that were identified. Also,
basic information should be obtained or verified,
including but not limited to number and
classification of service connections, daily
production peaks and averages, a flow diagram and
description of the major facilities, and a log of
customer complaints.
Management Assessment
Although the owners and managers are the primary
focus of this session, the operations and
maintenance personnel should also participate.
During this phase, the inspector will assess the
adequacy of programs and procedures including
SDWA compliance sampling, source protection,
cross-connection control, contingency plans,
corrosion control, safety, training, distribution
system flushing and pressure testing, financial
management, capital improvement, maintenance of
records, preventive maintenance, and standard
operating procedures. The inspector will also
assess how the utility deals with customer
complaints and whether staffing is adequate.
Finally, the inspector should review the operating
records (from in-house monitoring) in preparation
for the next phase of the on-site inspection.
Facility Walk-Through
It is imperative to the successful outcome of a
sanitary survey that the individuals responsible for
operation and maintenance (O&M) participate in
this phase. The inspector should begin at the water
source and work through the system (following the
"water stream") including the distribution system
and the pumping and storage facilities. At each
step in the process the inspector should conduct
visual observations and ask the O&M staff specific
questions about the process, equipment, and O&M
strategies employed. The manner in which
questions are posed to the operators should not be
suggestive in nature. For example, an accurate
answer is more likely to be obtained when asking,
"How do you determine when to backwash a
filter?" rather than, "You always backwash the
filter prior to an increase in filtered water turbidity,
right?" Another rule of thumb is never assume
anything. Even if the inspector thinks that he
knows the answer to a particular question, he
should ask it anyway. The answer will build on the
inspector's assessment of the operator's knowledge
and may lead to an additional series of questions
regarding the system.
NOTE: The inspector should not attempt to
adjust or operate any of the plant equipment.
Inspector's Assimilation of Findings
At this stage, the inspector should work alone to
complete the survey form and identify and
prioritize the sanitary deficiencies that he noted.
Top priority should be given to the sanitary
deficiencies that are determined to pose an
imminent threat to public health. This is the time
when the inspector should, if necessary, seek advice
from peers or supervisors in the primacy agency
office with regard to findings and actions to be
taken. The inspector also should use this time to
prepare for the debriefing.
Debriefing
Prior to leaving the site, the inspector should meet
again with the individuals who attended the initial
meeting and brief them on the sanitary deficiencies
that were identified, in order of priority. The
inspector should explain what action will result
from the survey and advise the water system
representatives that a report of findings and
recommendations will be prepared and provided to
them. The report will include a list of any
significant deficiencies, which will require system
follow-up. All important issues should be covered
in the debriefing so there are no surprises in the
final written report.
1-5
-------
How to Conduct a Sanitary Survey
Caution: As the inspector, your recommendations
may be to "fix something," but you are not
required to specify exactly how to fix it. If you are
in doubt, it may be better to return to the office and
discuss your findings before you make specific
recommendations and priorities.
Follow-up
Summary of Activities
Briefly, the activities during this period are:
Finalize documentation and prioritization of
all sanitary deficiencies that were identified
during the on-site investigation.
Complete the formal sanitary survey report,
including options for correcting the sanitary
deficiencies and sources of technical
assistance. Also identify any differences
between the findings in the written report
and the oral debriefing.
Notify appropriate organizations of the
results.
Follow up on questions asked by water
utility personnel.
The Sanitary Survey Report
Importance of Report
The sanitary survey report is an important
component of a sanitary survey.
The survey report is an important tool for tracking
compliance with the Safe Drinking Water Act and
for evaluating a system's compliance strategy.
Perhaps more important, it provides a record that
will support enforcement actions and allow future
inspectors to track progress. It also provides
information much needed during emergenices and
when technical assistance providers are on site. It
is the inspector's responsibility to the water system
and to the public to provide an accurate and
detailed description of improper operation or other
system deficiencies in a sanitary survey report.
Along with the verbal communication that occurs
during a sanitary survey, the written report can be
used to motivate corrective actions. This
motivation can be generated by the professional
nature of the report and an explanation of why the
corrective actions in the report are necessary. If the
sanitary survey inspector sends an accurate,
detailed report in a timely manner, the water system
personnel will, in most cases, perceive the survey,
the inspector, and the inspector's organization as
professional. This perception can foster confidence
among system personnel and a willingness to
cooperate in the correction of sanitary defects.
Official Notification
The sanitary survey report constitutes the official
notification of the evaluation results.
Undocumented verbal communication is not
reliable. Important information, such as violations
or required corrective actions, must be documented
in the sanitary survey report. The completed report
should reiterate the information presented to system
personnel by the inspector at the end of the on-site
evaluation. If the written evaluation is different
from the oral debriefing, the inspector should
inform the water system manager in advance.
The report itself can be as brief as a letter, if few
deficiencies are found, but it must be as detailed as
necessary to convey to the water utility what
deficiencies exist and what must be done to correct
them. However, by just listing the deficiencies, the
inspector may not accomplish the objective of
informing the system of a problem and seeking its
correction. The inspector is often the water system
manager or operator's only contact in discussing
the technical operation of their facilities. It is
sometimes incorrectly assumed that all managers or
operators can understand the inspector's comments
and technical references. Even if the system
personnel understand what the inspector wants, it
will be quite unlikely that corrective actions will be
taken if they cannot understand the reason for
doing them. The report should describe the
problems in basic terms and explain the reasons
they must be corrected. An explanation of how a
problem adversely affects the system is more likely
to motivate the system operator to correct it. The
report should be sent "return receipt requested" to
document receipt by the system.
Report Content
The report should contain:
1-6
-------
Chapter 1 - Organizing the Sanitary Survey
The date the survey was conducted and by
whom.
The names of those present during the
survey, besides the inspector.
A schematic of the system and, when
possible, photographs of key components.
A schematic of any treatment facilities
showing locations of chemical injection.
The survey findings and a discussion of any
differences in the findings presented in the
debriefing and the final report.
A list of all significant deficiencies with
specific recommendations for correction and
with deadlines for completion.
The inspector's signature.
A listing of all other sanitary deficiencies, in
order of priority, that should be addressed to
enhance water system operations and safety.
Results of Documentation
No matter how professional the sanitary survey
was, how involved or detailed the field aspects of
the survey were, or how many deficiencies were
pointed out verbally during the inspection, it is
important that all finding be documented in writing
so the system's owners and managers are made
aware of deficiencies that require correction. In
addition, if properly detailed documentation is not
registered by the use of sanitary survey forms and
a sanitary survey report, it will be very difficult to
use any of the survey findings for enforcement
purposes. Remember, when significant violations
are found, a compliance schedule, consent
agreement, administrative order, or litigation may
be necessary to ensure prompt and proper
correction.
Corrective Action
Options
To ensure that sanitary deficiencies are eliminated
(at a minimum, the significant deficiencies), the
sanitary survey inspector should provide the water
utility with options, where applicable, for making
improvements. Approaches to correcting sanitary
deficiencies can include:
Correction of problems by the water system
staff, their consulting engineers, or
contractors.
Technical assistance to the water utility by a
regulatory agency, organizations that
specialize in training and technical
assistance, or peers at other water systems.
Technical assistance specifically for surface
water systems.
A combination of any or all of these may be
appropriate, based on the type and severity of the
sanitary deficiencies.
In-House Corrective Action
At water systems with trained and competent staff,
many items identified as sanitary deficiencies can
be dealt with in house. A concern for the inspector
in this case may be, "How did the system get into
this condition, or why did the water utility manager
or operator allow the system to get to this
condition?" The inspector's recommendations
should consider changes to management and
operating procedures, as well as actions to correct
specific deficiencies, in order to reduce the
potential for continuing deficiencies. Once a
problem is pointed out and explained to a
competent and conscientious operator, he or she
likely will deal with the problem immediately and
with long-term compliance in mind.
Technical Assistance and Training
Water systems, especially publicly owned systems,
usually are not out of compliance by choice. Most
would like to be in compliance, but may need some
assistance in determining the cause of their
performance problems and in planning to correct
the performance problems and achieve compliance.
This assistance often takes the form of training and
on-site, over-the-shoulder, system-specific technical
assistance. The integration of training and technical
assistance into the overall enforcement strategy
has, in many states, proven to be the most effective
method for achieving and maintaining compliance
while promoting a partnership between the water
system, the regulatory staff, and the training and
technical assistance providers. Technical
1-7
-------
How to Conduct a Sanitary Survey
assistance, as it relates to sanitary surveys, means
providing suggested approaches to analyzing and
solving problems that contribute to sanitary
deficiencies.
Sources of Technical Assistance
Technical assistance and training resources vary
from state to state, can take many forms, and
involve a variety of approaches. Many states have
developed a means by which assistance can be
provided to a water system either at its request or
through a referral from a sanitary survey inspector.
In most states, the state primacy agency provides
some form of technical assistance either directly or
through an agency grantee (a technical assistance
provider). Often, field inspectors provide resource
listings, referrals, and other forms of general
technical assistance. Many states have a state
environmental training center or other organization
that can provide more specific technical assistance
to explain and demonstrate exactly what to do to
resolve problems. Private-sector consulting
services are also available in most states.
Approach to Assistance
The information given during technical assistance
or training is important. Unless the solution is
obvious, technical assistance should be given only
after the entire system has been surveyed. There
are two reasons for this approach. First, the
objective of the inspection is to evaluate the entire
water system. If inspectors spend excess time
trying to determine the causes of problems, they
have changed their primary objective and may very
well overlook a serious sanitary deficiency.
Isolating the cause of a water system problem may
be time-consuming and can be difficult without
sampling and analytical support. Competent
operators will have already evaluated and ruled out
the more common causes of problems. The second
reason for surveying the entire system is that there
may be conditions contributing to problems
throughout the system. Consequently, judgment
should be reserved until the entire system has been
reviewed.
Composite Correction Program
One form of technical assistance specifically for
surface water systems is a comprehensive
performance evaluation (CPE) of the treatment
process to determine performance-limiting factors.
The data and information generated by the CPE
are used in the follow-on comprehensive technical
assistance (CTA) program. The CPE identifies and
prioritizes factors limiting plant performance, and
the CTA attempts to correct each
performance-limiting factor. This combined CPE/
CTA approach is also known as a composite
correction program (CCP). Implementation of the
CCP is time-intensive and often requires daily
on-site evaluations and over-the-shoulder technical
assistance, as well as management of capital
improvements.
The Use of Red Flags
The sanitary survey often generates the data and
information that identify a treatment facility as a
potential candidate for the CCP process. The
sanitary survey looks at the same areas as the CPE
(albeit to a lesser degree), but provides a more
comprehensive overview of the entire water system,
from the source to the point of distribution. Much
of the information generated by the sanitary survey
will be incorporated into the CPE. The areas and
conditions where this integrated approach works
well are highlighted throughout the text. Indicators
or red flags that identify conditions in a plant that
make it a good candidate for a CPE are listed
below. (See also Chapter 6 - Water Treatment
Processes)
Hydraulic Loading
Hydraulic overload of unit processes.
Maximum hydraulic flow rate for short
periods of time.
Rapid increases in plant flow.
Chemical Feed
Calibration curves are not available for
chemical feed pumps.
The operator cannot explain how
chemicals, such as polymers, are diluted
prior to application.
The operator cannot determine the
chemical feed setting for various doses.
The operator does not adjust chemical
feed rales for vary ing raw water quality
conditions.
The operator cannot calculate chemical
feed doses (e.g., cannot convert a desired
mg/L dose to Ib/day or mL/min to allow
proper setting of the chemical feeder).
1-8
-------
Chapter 1 - Organizing the Sanitary Survey
Chemicals are used in combinations that
have detrimental effects on plant
performance. An example is the practice
of feeding lime and alum at the same
point without consideration of the
optimum pH for alum coagulation.
Chemical feed rates are not adjusted
when plant flow rate changes.
Chemical coagulants are not used when
raw water turbidity is low (e.g., less than
0.5 to 1.0 NTU.)
Rapid Mix
The rapid mixer is broken or intentionally
taken out of service (e.g., to conserve
power because "it does not improve
performance").
Flocculation
Variable-speed flocculation drives are not
adjusted (e.g., they remain at the setting
established when the plant was
constructed).
Sedimentation
Sludge is not routinley removed from
sedimentation basins (e.g., routine sludge
withdrawal is not practiced).
Filtration
Individual filter performance is not
monitored.
Rapid increases in overall plant flow rate
are made without consideration of filtered
water quality. Filter performance after
backwash is not monitored.
Filters are removed from service without
reducing plant flow rate, resulting in the
total plant flow being directed to the
remaining filters.
There is no clear rationale to determine
filter backwash frequency, duration, or
flow rate.
Filters are operated for excessive lengths
of time between backwashings.
Operators backwash filters only when
effluent turbidity increases.
Filters have significantly less media than
specified, damage to underdrains or
support gravels, or a significant
accumulation of mudballs, and these
conditions are unknown to the operating
staff because the filters are not examined
routinely.
Obvious problems in backwash water
distribution are observed during a
backwash cycle.
The purpose and function of the rate
control device cannot be described.
" The flow controllers are not functioning
properly.
Process Monitoring and Control
Jar tests or other methods (e.g., streaming
current monitor, zeta potential, or pilot
filter) of coagulation control are not
practiced.
The operator does not understand how to
prepare ajar test stock solution and to
administer various chemical doses to the
jars.
The only testing conducted is raw water
turbidity (daily) and finished water
turbidity, as collected from a clearwell
sample on a daily basis.
Settled water turbidity is not measured
routinely (e.g., minimum of once each
shift).
Individual filtered water quality is not
monitored.
There are no records available
documenting performance of the
individual sedimentation or filtration unit
processes.
Limitations
Inspectors should temper any advice with a
realistic assessment of their personal experience
and knowledge of the problem. If erroneous
information is provided, money, time, and
credibility can be lost while the sanitary deficiency
continues. Inspectors who have limited experience
should refer problems to more experienced
personnel. Incorrect technical assistance that
does not correct the problem can have
ramifications ranging from loss of credibility to
challenges to authority regarding corrective
actions.
1-9
-------
Drinking Water
Regulations
In addition to specifying Maximum Contaminant
Levels (MCLs), the federal drinking water
regulations address sampling location, frequency,
recordkeeping, and other requirements that should
be subject to compliance determinations during a
sanitary survey. There may also be other
requirements found in national safety standards,
such as those promulgated by the Occupational
Safety and Health Administration (OSHA),
variances or exemptions, or enforcement orders
that should be reviewed during a sanitary survey.
In order to make these on-site compliance
determinations, the inspector should be able to meet
the following objectives.
Learning Objectives
By the end of this chapter, learners should be able:
To define a sanitary survey as specified in
EPA regulations and explain the
comprehensive nature of sanitary surveys.
To explain the importance of making an
accurate determination of population served
by the system and number of service
connections.
To determine if a water system is a public
water system subject to EPA regulations
adopted by the state.
To determine if a public water system is
properly classified (as community; non-
transient, non-community; or transient, non-
community).
To explain the importance of and determine
whether the system has made modifications
to its sources, treatment, or distribution
system without state approval.
To describe the on-site compliance
determinations that should be made for
various provisions of the National Primary
Drinking Water Regulations (NPDWRs)
adopted by the state including siting; total
coliform; surface water treatment; lead and
copper; organic, inorganic and radiological
contaminants; disinfectants and disinfection
byproducts; reporting including the
consumer confidence report; recordkeeping;
and public notification.
To determine whether the system is
operating in accordance with the National
Secondary Drinking Water Regulations
(NSDWRs) as adopted by the state.
To determine compliance with American
National Standards Institute (ANSI) and
National Sanitary Foundation (NSF)
standards for direct and indirect additives.
Examine compliance with other
requirements such as OSHA regulations.
To determine if the system is complying with
conditions set forth in variances,
exemptions, or compliance orders.
Data Collection
To efficiently determine a system's compliance with
regulatory requirements, the inspector must rely on
information that is available in the state primacy
agency office, as well as that gathered in the field.
Various reports, correspondence, engineering
studies, and monitoring data are important sources
of information for determining a system's
compliance. They typically are available in the
office for review and evaluation. Prior to an
2-1
-------
How to Conduct a Sanitary Survey
inspection, the inspector should review the
following:
Any violations of MCLs, treatment
techniques, monitoring, or reporting.
Current information on population served
and number of service connections.
State-approved coliform sample siting plan.
State-approved locations for disinfection
byproduct samples.
Consistency with NSDWRs.
Variances or exemptions that apply to the
system.
Compliance orders that apply to the system.
Documentation of state approval for the
installation of or changes to the system.
Regulations and Standards to
Consider
The inspector should review the following
regulations prior to the inspection:
EPA or state primary and secondary
drinking water regulations.
State design standards or guidelines.
ANSI/NSF standards.
Drinking Water Regulations
Basic Information
Safe Drinking Water Act of 1974. In recognition
of potential public health risks associated with the
nation's drinking water, Congress enacted the Safe
Drinking Water Act (SDWA) in 1974. The Act was
intended to ensure the delivery of safe drinking
water by public water systems and to protect
underground water sources from contamination.
1986 SDWA Amendments. In 1986, Amendments
to SDWA were signed into law. They greatly
expanded the number and type of contaminants to
be regulated in drinking water and they
strengthened EPA's enforcement authority. The
passage of these Amendments was the result of
heightened concern about the potential
contamination of public water supplies by toxic
chemicals and an increase in the number of
waterborne disease outbreaks caused by
microbiological contaminants. Congress was also
concerned about the lack of speed with which EPA
was developing regulation standards for drinking
water.
1996 SDWA Amendments. In 1996, Congress
again amended SDWA. The new law includes, for
the first time, provisions for state revolving loan
funds to improve water systems. It also requires
EPA to base regulations on risk assessment and
cost-benefit considerations. The statute requires
EPA to identify the best treatment technologies for
various sizes of systems, establish guidelines for
operator certification, and provide monitoring relief
for small systems. Source water protection and
consumer confidence reports are part of the statute.
Code of Federal Regulations. Final EPA
regulations are published (or "promulgated") in the
Federal Register. Federal regulations are compiled
annually and codified in the Code of Federal
Regulations (CFR). EPA's regulations are found in
Title 40 of the CFR (40 CFR). NPDWRs are
incorporated or codified in 40 CFR Part 141,
which is divided into subparts and sections for
specific regulatory provisions. For example,
coliform monitoring requirements are found in
section 21 of Part 141 (40 CFR 141.21). The CFR
is available from the Government Printing Office in
Washington, D.C., and EPA's regulations can be
accessed and downloaded from its Web site
(www.epa.gov/epacfr40/chapt-I.info/chi-toc.htm).
The EPA Drinking Water Hotline (1 -
800-426-4791) provides another easily accessible
source of information on SDWA regulations.
National Primary Drinking Water Regulations
(40 CFR Part 141). SDWA requires EPA to
establish regulations for contaminants in drinking
water that may have an adverse effect on the public
health. These NPDWRs include MCLs or
treatment techniques for more than 100
contaminants. Monitoring and testing procedures
also are specified.
NPDWR Implementation. Congress intended that
SDWA requirements be implemented primarily by
2-2
-------
Chapter 2 - Drinking Water Regulations
the states. Therefore, SDWA requires EPA to
define the requirements for allowing states to
implement and enforce state regulations. State
regulations must be at least as stringent as the
federal regulationsand they can be more
stringent. A state whose program has been
approved by EPA is granted primary enforcement
authority ("primacy") for its drinking water
program. Primacy requirements are codified in 40
CFR Part 142, National Primary Drinking Water
Regulations Implementation. EPA may grant a
state primary enforcement authority when the EPA
Administrator determines that a state has met the
following requirements:
It has adopted drinking water regulations no
less stringent than the NPDWR.
Its definition of a public water system is
consistent with the definition in SDWA.
It has adequate enforcement authority and
procedures.
It maintains an inventory of public water
systems.
It has a systematic program for conducting
sanitary surveys of public water systems,
with priority given to systems not in
compliance with the NPDWRs.
It has a program to certify laboratories that
will analyze water samples.
It has a certified laboratory that will serve
as its principal laboratory.
It has a program to review the design and
construction of new or modified systems.
It has adequate recordkeeping and reporting
requirements.
It has an adequate plan to provide for safe
drinking water in emergencies.
Its variance and exemption requirements are
as stringent as EPA's (if the state chooses to
allow variances or exemptions).
In primacy states (every state but Wyoming and the
District of Columbia), state personnel derive their
authority from state, rather than federal, drinking
water regulations. Therefore, whenever a federal
regulation is cited in this document, the
inspector needs to find and use the equivalent
state regulation.
National Secondary Drinking Water
Regulations. EPA also sets National Secondary
Drinking Water Regulations (NSDWRs), which are
codified in 40 CFR Part 143. These regulations
address drinking water contaminants that primarily
affect the taste, odor, or color of drinking water.
Such aesthetic considerations are a concern
because if a system provides water that is
unappealing to the senses, its users may seek
alternative supplies, some of which may be
unsanitary. In addition, there may be health
implications at considerably higher concentrations
of these contaminants. Although not federally
enforceable, the secondary regulations are intended
as guidelines for states and public water systems.
Individual states may choose to adopt and enforce
these secondary regulations.
Public Water Systems
Three important field determinations made during a
sanitary survey are:
How many people are served by the system.
How many service connections the system
has.
Whether service is provided for at least 60
days a year.
This information determines whether a system
meets the definition of a public water system in
SDWA and whether it is subject to the NPDWRs.
Types of Systems. Although the NPDWRs apply
to all public water systems, the regulations make a
distinction between community and non-community
systems. A further distinction is made between
transient and non-transient, non-community
systems.
Definition of a PWS. A public water system is a
system for providing water for human consumption
through pipes or other constructed conveyances
which has at least 15 service connections or
regularly serves at least 25 people at least 60 days
a year. A system includes any collection, treatment,
storage, and distribution facilities under control of
2-3
-------
How to Conduct a Sanitary Survey
the system operator and used primarily in
connection with its operation and any collection or
treatment facilities not under such control that are
used primarily in connection with such a system.
Community Water Systems. Community water
systems (CWSs) serve residential populations of at
least 25 people or 15 service connections
year-round. Users of community systems are likely
to be exposed to any contaminants in the water
supply over an extended time period, and are thus
subject to both acute and chronic health effects.
Non-Community Water Systems.
Non-community water systems do not serve
permanent residential populations. Non-community
systems are either transient nor non-transient
systems.
Non-transient, non-community water
systems (NTNCWSs) serve on a regular
basis at least 25 of the same persons at least
6 months per year. Like community systems,
these systems can expose users to drinking
water contaminants over an extended time
period (subjecting users to risks of both
acute and chronic health effects). Schools,
churches and factories that have their own
water systems fall under this definition.
Transient, non-community water systems
(TNCWSs) serve short-term users. As a
result, the users are exposed to any drinking
water contaminants only briefly and are
subject to experiencing acute health effects.
Examples of TNCWSs are restaurants, gas
stations, hotels, and campgrounds.
These distinctions, and others such as service
population and water source, are important because
EPA may regulate these systems differently.
Population served determines sampling frequency
in a number of regulations, such as the total
coliform rule, lead and copper rule, inorganic
chemicals rule, disinfectants and disinfection
byproducts rule (D/DBPR), and the surface water
treatment rule (SWTR). Most water system
operators will know precisely how many individual
service connections their systems have, but not
necessarily the population served by the system.
Some states will use a factor (i.e., estimated
persons per connection) multiplied by the number
of service connections to estimate population.
During the survey, the inspector should determine
if the state records on population and number of
service connections are up-to-date. Further
evaluation will be needed to determine if changes in
population will affect the system's status relative to
any SDWA requirement.
An inspector needs to know a system's
characteristics to know whether the system is
properly classified and, therefore, which
regulations are applicable.
Sanitary Surveys and the
Regulations
The regulations define a sanitary survey as follows:
Sanitary survey means an on-site review of the
water source, facilities, equipment, operation,
and maintenance of a public water system for
the purpose of evaluating the adequacy of such
source, facilities, equipment, operation, and
maintenance for producing and distributing safe
drinking water. (40 CFR 141.2)
Clearly, the definition requires a comprehensive
review of the entire water system from source to
treatment to storage and distribution, including
operation and maintenance of all the system's
facilities. Following is a discussion of specific
determinations the inspector should make for
current SDWA rules.
Siting Requirements
Advance Notification. The regulation at 40 CFR
141.5 requires water systems to notify the state
before a new water system is constructed or the
capacity of an existing system is increased. The
regulation also specifies that the system should
avoid siting in areas subject to earthquakes, floods,
and fires.
The inspector should be alert to any changes that
have been made without state approval. Facilities,
particularly wells that may be subject to flooding,
should be evaluated. The inspector should
recommend flood-proofing if facilities are located
£} /-!!*->
Total Coliform Requirements
Sample Site Plan. The Total Coliform Rule (TCR)
(40 CFR 141.21) requires a water system to have a
2-4
-------
Chapter 2 - Drinking Water Regulations
written sample siting plan that is subject to state
approval. The inspector should verify that the
system has an approved plan and is using it. The
inspector should also evaluate the plan to determine
if it meets the requirements of the TCR. The rule
requires collecting samples "which are
representative of water throughout the distribution
system." The rule also contains a table that shows
the minimum number of samples required based on
population served. In reviewing the sample siting
plan, the inspector should note that more samples
than the minimum may be required in order to be
"representative." Some of the issues to be
concerned with are short chlorine contact time
(CT) to first customer, dead ends, long residence
time in the system, multiple sources, storage tanks,
areas of low pressure, biofilm, and
cross-connections.
Survey Frequency. The TCR also contains
specific requirements on the minimum frequency
with which sanitary surveys must be conducted on
systems that collect fewer than five samples per
month (40 CFR 141.21 (d)). This requirement is
placed on the public water system, not the state.
However, the sanitary surveys must be conducted
by the state or a party approved by the state. Also,
the state must review the results of each sanitary
survey to determine whether the monitoring
frequency is adequate and what additional
measures, if any, the system needs to undertake to
improve drinking water quality. More recent rules
include special primacy requirements that establish
minimum components for sanitary surveys and
frequencies at which states must conduct them.
Type of System
Community water
system
Non-community
water system
Non-community
water system
using only
protected and
disinfected
ground water
Initial Survey
June 29, 1994
June 29, 1999
June^29, 1999
Subsequent
Surveys
5 years
5 years
5 years
Source: 40 CFR Part 141
Sanitary surveys can also be used to allow the
monitoring frequency for certain community
systems serving fewer than 1,000 persons to be
reduced to one coliform sample per quarter (40
CFR 141.21(a)(2)). They also can be used as a
basis for reduced monitoring for certain non-
community systems (40 CFR 141.21(a)(3)).
Variances. Variances may be granted from the total
coliform MCL if a system can demonstrate to the
state that a violation is due to persistent regrowth
in the distribution system, rather than from a
treatment lapse, a treatment deficiency, or a
problem in the operation or maintenance of the
distribution system (40 CFR 141.4(b)).
Surface Water Treatment Rule
General Requirements. Subpart H of 40 CFR
Part 141 (Filtration and Disinfection) contains
requirements for the filtration and disinfection of
surface water supplies and ground water supplies
under the direct influence of surface water (defined
as "subpart H systems"). The treatment technique
requirements consist of installing and properly
operating water treatment processes that achieve
99.9 percent removal and/or inactivation of
Giardia and 99.99 percent removal and/or
inactivation of viruses. Water systems have two
ways of complying with the SWTR requirements.
They can meet all the filtration avoidance criteria
in 40 CFR 141.71 and provide 99.9 percent
Giardia and 99.99 percent virus inactivation by
disinfection, or they can provide both filtration and
disinfection that, in combination, meet the removal/
inactivation requirements for Giardia and viruses.
Ground Water Under the Direct Influence of
Surface Water. As noted above, systems that use
ground water sources under the direct influence of
surface water are subject to the SWTR and,
therefore, are included in the definition of subpart
H systems. The state determination for direct
influence is based on site-specific measurements of
water quality (such as the occurrence of insects,
algae, or pathogens such as Giardia lamblia or
Cryptosporidium) or documentation of well
construction characteristics and geology with field
evaluation. A source subject to flooding, or the
alteration of a stream course bringing it closer to a
well, might result in a change in water quality.
During the survey, the inspector should evaluate
any conditions that might cause the state to alter its
2-5
-------
How to Conduct a Sanitary Survey
determination that a ground water source is not
influenced by surface water.
No Recontamination. Water cannot be subject to
recontamination by surface water after treatment,
for example, by using open, uncovered finished
water storage subject to runoff. During a sanitary
survey, the inspector should verify that treated
water is not subject to recontamination by surface
water.
First Customer. The removal and/or inactivation
requirements must be met before or at the first
customer. In many cases, the first customer is the
treatment plant itself. In some cases, a new first
customer may be added to the system. The
inspector should identify the first customer and
ensure that the requirements for removal and/or
inactivation are being met there.
Entry Point Residual. The disinfectant residual
entering the system residuals cannot be less than
0.2 mg/L for more than 4 hours and must be
monitored continuously. The only exception is
systems that do not provide filtration and serve
fewer than 3,300 persons; they may take grab
samples at specified frequencies in lieu of
continuous monitoring (40 CFR 141.74(b)(5)).
System Size by
Population
<500
501-1,000
1,001-2,500
2,501-3,300
Grab Samples per
Day
1
2
3
4
Residual in the Distribution System. The residual
must be detectable in 95 percent of the samples
taken in the system. Samples should be taken at the
same time and place as coliform samples. Systems
may also use a heterotrophic plate count (HPC) to
determine compliance. During the sanitary survey,
the inspector should verify that all conditions for
disinfection are being met. The inspector should
determine that residuals are measured at the proper
locations throughout the distribution system.
Testing techniques should also conform to the rule.
Qualified Personnel. The SWTR requires that
each system subject to it be operated by qualified
personnel. Compliance with the state's operator
certification program will meet this requirement
and, therefore, should be verified during the survey.
Unfiltered Systems Requirements. To avoid
filtration, a subpart H system must meet stringent
source water quality conditions and site-specific
conditions designed to ensure safe drinking water.
Source Quality Conditions. To meet the
avoidance criteria, unfiltered systems must
monitor raw source water immediately
before the first point of disinfection and
have a fecal coliform concentration of less
than or equal to 20/100 mL, or a total
coliform concentration of less than or equal
to 100/100 mL in at least 90 percent of all
measurements over the previous 6 months.
Also, the turbidity of the source water
cannot exceed 5 NTU at the same sampling
point (with some exceptions).
Site-Specific Conditions. In addition to the
source water quality conditions, systems
meeting the filtration avoidance criteria
must:
Comply with disinfection requirements
that:
Ensure 3 log Giardia lamblia and 4
log virus inactivation. (CT
[concentration of residual multiplied
times contact time] values are specified
in the rule and must be met at the first
customer.)
Provide redundancy of components or
automatic shut-off when the residual is
<0.2 mg/L.
Ensure a residual of 0.2 mg/L entering
the distribution system.
Provide a detectable residual in the
distribution system when measured at
the same time and place coliform
samples are collected.
Maintain a watershed control program
that minimizes the potential for
contamination by Giardia iamblia,
viruses, Cryptosporidium, and other
pathogens.
Be subject to an annual on-site
inspection. On-site inspections for
2-6
-------
Chapter 2 - Drinking Water Regulations
systems subject to the filtration avoidance
criteria are similar to sanitary surveys
and may be accomplished during sanitary
surveys. Items to be reviewed include:
Effectiveness of watershed control.
Condition of intake.
Facilities and operation and
maintenance (O&M) of disinfection.
Operating records.
Effectiveness of disinfection.
Needed improvements.
Waterborne disease outbreaks.
Compliance with MCLs for total
coliform and Stage 1 disinfectants and
disinfection byproducts.
Maintain compliance with the Total
Coliform Rule and the Disinfectants/
Disinfection Byproducts Rule.
During the sanitary survey, the inspector should
review the system's data on raw water quality and
its source water protection program. The inspector
also should check the available CT for compliance.
Filtered System Requirements. The requirements
that systems which use filtration must meet are
described below.
Filtration Requirements. Systems that are
unable to comply with all criteria to avoid
filtration must meet the 3 log Giardia
lamblia and 4 log virus inactivation and/or
removal requirements by using both an
appropriate filtration technology and
disinfection. Compliance with the treatment
technique requirements of the S WTR is
measured against turbidity performance
criteria specific to the type of filtration in
use (subject to state approval) and adequate
CT to inactivate the remaining Giardia
lamblia and viruses.
Turbidity Requirements. Minimum
turbidity performance criteria are
established in the SWTR for the various
filtration methods. Regardless of the
filtration method, however, the turbidity
level of filtered water must never exceed 5
Nephelometric Turbidity Units (NTU).
Conventional and Direct Filtration.
Filtered water turbidity must be less than or
equal to 0.5 NTU in 95 percent of the
measurements taken every month. At the
state's discretion, levels less than or equal to
1 NTU may be permitted in 95 percent of
the measurements on a case-by-case basis. If
levels greater than 0.5 NTU are permitted in
the system being inspected, the inspector
should verify that the system is in
compliance with any conditions placed on it
by the state, such as redundant disinfection
facilities. Note that since January 1, 2001,
subpart H systems serving at least 10,000
people are subject to enhanced filtration and
disinfection requirements in 40 CFR
141.170 to 175. Smaller subpart H systems
(those serving fewer than 10,000 persons)
have been subject to very similar
requirements since January 12, 2002. For
conventional and direct filtration plants, the
above reference performance criteria (i.e.,
0.5 NTU and 5 NTU) will be reduced to 0.3
NTU and 1 NTU.
Slow Sand Filtration. Filtered water
turbidity must be less than or equal to 1
NTU in 95 percent of the measurements
taken every month. A state may allow a
higher level of turbidity if it determines that
there is no significant interference with
disinfection at the higher turbidity level. The
turbidity of slow sand filter effluent must
never exceed 5 NTU. The inspector should
verify that these conditions are being met if
the state allows the system to exceed 1
NTU.
Diatomaceous Earth Filtration. Filtered
water turbidity must be less than or equal to
1 NTU in 95 percent of the measurements
for each month. The turbidity level of
representative samples may at no time
exceed 5 NTU.
Other Filtration Technologies. Alternative
technologies must be shown to be capable of
consistently achieving 99.9 percent and
99.99 percent removal and/or inactivation of
Giardia lamblia cysts and viruses,
respectively. Systems that can make this
demonstration are required by the original
SWTR to comply with the turbidity
performance requirements for slow sand
filtration. Since January 1, 2001, subpart H
systems serving at least 10,000 persons
2-7
-------
How to Conduct a Sanitary Survey
must demonstrate to the state that alternative
technologies are capable of 99 percent
Cryptosporidium, 99.9 percent Giardia
lamblia, and 99.99 percent virus removal
and/or inactivation. For systems that can
make this demonstration, the state will
establish turbidity performance criteria at a
level that ensures adequate cyst removal.
l\irbidity Measurements. The inspector
should verify that the required turbidity
measurements are being made, that the
results are accurate and reliable, that
sampling frequency, locations, and
analytical procedures are appropriate, and
that the turbidity readings comply with the
SWTR requirements. The inspector should
check for compliance with CT requirements
and make sure the system operator is
properly doing the daily calculations.
Operation and Maintenance. The inspector
should verify that the required filtration and
disinfection facilities are in place and are
properly operated and maintained.
Interim Enhanced Surface Water
Treatment Rule (IESWTR)
At 40 CFR Part 141, subpart P, Enhanced
Filtration and Disinfection (40 CFR 141.170-. 175),
are additional requirements for subpart H systems
that serve 10,000 or more persons. These
requirements took effect January 1, 2001, and are
primarily to address public health risks from
Cryptosporidium. They include:
More stringent turbidity limits for combined
filter effluent from conventional and direct
filtration plants.
Continuous monitoring of individual filter
effluent in conventional and direct filtration
plants.
Follow-up actions for exceeding "trigger"
turbidity levels in two consecutive
measurements taken 15 minutes apart at an
individual filter for conventional and direct
filtration plants.
Requirements for all filtered systems to
remove 99 percent (2 log) Cryptosporidium
cysts.
Disinfection profiling and benchmarking
requirements for systems with elevated
levels of disinfection byproducts.
Measures to control Cryptosporidium in the
watersheds of unfiltered systems meeting the
criteria for avoiding filtration.
In addition, 40 CFR Part 142 now requires states
to describe how they will provide sanitary surveys
for subpart H systems that include all eight
essential elements on a frequency of at least once
every 3 years for community systems and every 5
years for non-community systems. Community
subpart H systems whose performance is
determined by the state to be outstanding may have
sanitary surveys conducted at intervals of up to 5
years.
Inspectors should check to see if systems that are
required to prepare disinfection profiles have done
so. The system's disinfection benchmark should be
calculated and any planned changes in disinfection
practices should be discussed. Also, the inspector
must, in the sanitary survey report, designate any
sanitary deficiencies deemed by the state to be
"significant" deficiencies. Inspector follow-up is
then necessary to ensure the system responds in
writing and addresses the significant deficiencies.
Long Term 1 Enhanced Surface Water
Treatment Rule (LT1 ESWTR)
EPA promulgated this rule on January 12, 2002.
The rule applies requirements similar to those of
the IESWTR to systems that use surface water or
ground water under the direct influence of surface
water and serve fewer than 10,000 persons.
Filter Backwash Recycling Rule
(FBRR)
EPA promulgated this rule (40 CFR 141.76) on
JuneS, 2001.
The inspector should determine whether direct and
conventional filtration plants recycle spent filter
backwash water, sludge thickener supernatant, or
liquids from dewatering processes. Plants that
recycle regulated flows must bring them back to the
head of the plant (after June 1, 2003) or to an
alternative location approved by the state. The state
will also determine if treatment or equalization of
the recycle stream is necessary. The inspector
2-8
-------
Chapter 2 - Drinking Water Regulations
should also make sure the plant is in compliance
with FBRR monitoring and reporting requirements.
Lead and Copper Rule
Under 40 CFR 141.80 to 91, community and non-
transient, non-community water systems must
collect first-draw samples from strategically
located service connections and have them analyzed
for lead and copper. If the levels of lead or copper
exceed action levels (0.015 mg/L for lead and 1.3
mg/L for copper) in more than 10 percent of the
required samples, corrective action must be taken.
The inspector should verify that the system has
taken the required first-draw samples. It is
particularly important with small systems to make
sure they are sampling at appropriate locations and
times. Small schools, for example, often sample at
the beginning of the school year or from taps that
have not been used for weeks; they exceed action
levels because of the excessive time water was in
the line.
When action levels have been exceeded, the
inspector must ensure that the appropriate follow-
up corrective actions including treatment, when
necessary, have been taken.
Stage 1 Disinfectants and Disinfection
Byproducts (D/DBPs)
Community and non-transient, non-community
systems that chemically disinfect their water must
meet the requirements of 40 CFR Part 141, subpart
L, Disinfectant Residuals, Disinfection
Byproducts, and Disinfection Byproduct
Precursors. Portions of subpart L also apply to
transient, non-community systems that use chlorine
dioxide. Components of subpart L that inspectors
must be aware of include:
MCLs for disinfection by-products
including TTHMs, haloacetic acids
(HAAS), bromate and chlorite.
Maximum residual disinfectant levels
(MRDLs) for chlorine, chloramines, and
chlorine dioxide.
Monitoring plan requirements.
Enhanced coagulation and enhanced
softening requirements to address DBF
precursors for subpart H systems that have
conventional or softening plants.
It should be noted that each system affected by this
rule must develop and implement a monitoring
plan. The system must then maintain the
monitoring plan and make it available for
inspection by the state and general public (systems
serving more than 3,300 persons must submit their
plans to the state). The inspector should review the
monitoring plan while on site to ensure that
monitoring is in accordance with the rule.
Inorganic and Organic Chemicals
Monitoring requirements for inorganic and organic
chemicals are contained in 40 CFR 141.23 and 40
CFR 141.24, respectively. For both groups of
contaminants, samples are required at the entry
points to the distribution system. Inspectors should
verify that all sources are appropriately monitored
at the entry point. It is important to note that
transient, non-community systems are required to
monitor for nitrate and nitrite.
Waivers for Volatile Organic Chemicals,
Inorganic Chemicals, and Synthetic Organic
Chemicals. Waivers from monitoring requirements
can be obtained based on knowledge of previous
use of a contaminant including transport, storage,
or disposal. If use is unknown, waivers can be
based on sources of contamination resistance and
wellhead or watershed protection. These factors
should be evaluated during a sanitary survey to
determine if conditions have changed that would
cause the state to reconsider a waiver previously
granted or to grant a new waiver.
Asbestos monitoring, unless a waiver is
received, must be done at a tap served by
asbestos cement pipe. This should be
verified.
Reduced monitoring for inorganic chemicals
is based on factors that can affect
contaminant concentrations. These include:
Changes in ground water pumping
rates.
Changes in the system's configuration,
Changes in the system's
operating.procedures.
Changes in stream flow or
characteristics.
2-9
-------
How to Conduct a Sanitary Survey
During a sanitary survey, the inspector
should determine that no changes have
occurred that would cause the state to
reconsider a waiver or reduced monitoring.
A state may grant a waiver from monitoring
for organic chemicals based on a system's
vulnerability to contamination.
Radiological Contaminants
Community water systems are required to
sample for radiological contaminants.
Compliance with radiological monitoring
requirements should be checked by the
inspector while on site or when reviewing
the system's files prior to the sanitary
survey.
Direct and Indirect Additives
Contaminants Not Regulated. During a sanitary
survey, it is important to be alert to contaminants
other than those that are regulated under the
national primary or secondary regulations. Of
particular concern are contaminants that may be
added during the process of collecting, treating,
storing, or distributing drinking water.
Treatment, Chemicals, and Coatings. Treatments,
chemicals, and coatings in contact with drinking
water must be certified as meeting certain industry
consensus standards for water contact or treatment.
The certification itself can be made by an agency
acceptable to the state to test and certify that
products meet the standard.
NSF Standard 60. The National Sanitation
Foundation (NSF) is the organization responsible
for developing Standard 60, which covers direct
additives to drinking water. Examples of direct
additives include water treatment chemicals such as
chlorine, polymers, orthophosphates, coagulants
and aids, fluoride compounds, copper sulfate, and
corrosion control chemicals.
40 CFR 141.111. EPA regulations place limits on
two contaminants that may be contained in organic
polymers used in coagulation and filtration. The
water system must annually certify to the state in
writing that the dose and monomer level do not
exceed the following:
Acrylamide, 0.05 percent dosed at 1 ppm.
Epichlorohydrin, 0.01 percent dosed at 20
ppm.
During a survey, the inspector should determine
that the system is complying with these
requirements.
NSF Standard 61. NSF Standard 61 covers
indirect additives. This category of additives
includes products that come into contact with
drinking water or into contact with treatment
chemicals, such as filter media, coatings, liners,
solvents, gaskets, welding materials, pipes, fittings,
valves, chlorinators, and separation membranes.
Products certified as meeting NSF Standard 60 or
61 can be identified by markings on them or their
packaging. Lists of certified products are available
from the certifying agencies.
State Requirements. Although there are no federal
regulations requiring that additives used must meet
NSF Standards 60 and 61, many states have or will
adopt such requirements. In any event, an inspector
should determine during a sanitary survey whether
the system is using approved additives and is aware
of the additives certification program.
Operator Certification
EPA guidelines specify minimum standards for the
certification and recertification of operators of
community and non-transient, non-community
public water systems. All states have requirements
that meet the EPA guidelines. The inspector should
always check to make sure each system is in
compliance with the state requirements.
Consumer Confidence Report Rule
Since October 1999, and every July 1 thereafter,
community water systems must issue to their
customers annual drinking water quality reports
called consumer confidence reports (CCRs). The
report must include required source water
information, health information, detected
contaminants and violations incurred. The systems
must submit to the primacy agency copies of the
annual CCR and a certification that the CCR was
distributed to customers with information that is
correct and consistent with monitoring data.
Because submitted CCRs are subject to annual
review by the primacy agency, sanitary survey
efforts should be limited to verifying whether
2-10
-------
Chapter 2 - Drinking Water Regulations
copies of the CCRs are kept on file by the system
for at least 5 years.
Recordkeeping
There are a number of general recordkeeping
requirements specified in 40 CFR 141.33. In
addition, the SWTR (40 CFR 141.75) and the
Lead and Copper Rule (40 CFR 141.91) have
specific requirements.
The inspector should verify the availability of these
records at the water system during a sanitary
survey.
Other Records. In addition to records required by
federal regulation, the water system should
maintain a variety of other records to ensure the
continual proper operation and maintenance of the
system. These include monitoring plans for
disinfectants and disinfection byproducts;
disinfection profiles; maps of the system; as-built
plans; and water quality data from source,
treatment, and distribution. The availability and
security of these records should be evaluated
during a sanitary survey.
Records to Keep Retention Period
Bacteriological analysis
Chemical analysis
Actions to correct violations
Sanitary survey reports
Variance or exemption
Turbidity results
All lead and copper data
5 years
1 0 years
3 years
1 0 years
5 years
1 0 years
1 2 years
Data Integrity. SDWA and its regulations require
self-monitoring and self-reporting by water systems
to show compliance with the regulations. The
consequences of non-compliance can be severe
(e.g., compliance orders and penalties). Errors in
information reported to the state can result from
ignorance of proper testing procedures and
instruments that are out of calibration. Data
falsification is rare, but serious. During a survey
the inspector should be alert to intentional or
unintentional errors in data.
Variances, Exemptions, and Orders
Variances, exemptions, and compliance orders will
contain provisions requiring the public water
system to comply with certain conditions. (For
example, a compliance order will normally include
a schedule.) A sanitary survey can be used to
determine a system's progress in complying with
these conditions. Sanitary surveys can also be used
to determine, case by case, the need for, and the
possible conditions that may be set forth in, a
variance, exemption, or order.
Field Compliance Questions/Sanitary
Deficiencies
1. Is the information in the state files on
population served and number of service
connections accurate?
2. Is the information on the status of the
system correct (i.e., is it large enough to
be a public water system, and is its
classification as CWS, TNCWS, or
NTNCWS correct)?
3. Is the system in compliance with various
provisions of the NPDWRs, including
siting of facilities, coliform monitoring,
filtration and disinfection, lead and copper
corrosion control, organic and inorganic
contaminants, and direct and indirect
additives?
4. Has the system modified its source,
treatment process, chemicals used, or
distribution system without state
approval?
5. Is the system using chemicals and
coatings approved by ANSI/NSF or
another third party?
6. Is the system staffed by qualified
operators?
7. Are appropriate records maintained?
8. Is the system complying with conditions
set forth in any waivers, variances,
exemptions, or orders?
2-11
-------
How to Conduct a Sanitary Survey
9. Does the system have a written monitoring
plan for disinfectants and disinfection
byproducts?
10. Was the system required to prepare a
disinfection profile and, if so, is it
available for review?
Sanitary Surveys and Capacity
Development
The 1996 SDWA Amendments require states to
develop two programs: One is to ensure that new
community water systems and new non-transient,
non-community water systems have adequate
capacity before they can operate. The other must
provide a strategy to help existing public water
systems achieve and maintain capacity. Sanitary
surveys can be used to assess capacity at existing
systems.
Water system capacity (not to be confused with
production capacity as measured in units of water)
is the ability to plan for, achieve, and maintain
compliance with applicable drinking water
standards. For a system to have capacity, adequate
capability is required in three distinct, but
interrelated, areas:
Technical. The essential elements of
technical capacity are source water
adequacy, infrastructure adequacy, and
technical knowledge. These can be assessed
when reviewing the following sanitary
survey elements: source, treatment,
distribution, storage, pumps, monitoring and
reporting, management and operations, and
operator certification.
Managerial. The essential elements of
managerial capacity are ownership
accountability, staffing and organization,
and effective external linkages. These can be
assessed when reviewing the monitoring and
reporting, management and operations, and
operator certification elements of a sanitary
survey.
Financial. The essential elements of
financial capacity are revenue sufficiency,
fiscal management and controls, and credit
worthiness. Like technical capacity,
evidence of financial capacity can be found
in all elements of a sanitary survey.
In assessing capacity as part of a sanitary survey, it
is important to recognize the relationship between
sanitary surveys and capacity development:
Both attempt to identify deficiencies that
may jeopardize a system's ability to deliver
an adequate quantity or quality of water to
consumers.
Both require follow-up to accurately assess
and remedy a system's problems.
Both address technical, management and
financial issues.
The last point is especially significant. If you are
conducting thorough sanitary surveys, you are
probably already addressing many of the issues
that would be raised in a capacity development
assessment. The addition of a few questions-most
likely on managerial and financial issues-may be
necessary. Chapter 10 of this Guide provides some
additional questions related to managerial and
financial capacity.
A state may use the sanitary survey to screen
systems regarding capacity, since some inspectors
will not feel comfortable discussing managerial or
financial issues. However, basic questions can be
asked to assess whether more detailed follow-up by
other state personnel is warranted.
As you conduct a sanitary survey, be aware that
many of the questions you ask address capacity.
Think about the information in terms of capacity,
and you will have taken the few additional steps
required to complete a capacity assessment at the
same time as your sanitary survey.
2-12
-------
Water Sources
The source of water for a public water system is
the first area of concern in the multiple-barrier
approach to preventing waterborne disease.
Inspectors should determine the safety, adequacy,
and reliability of the source during a sanitary
survey.
Learning Objectives
By the end of this chapter, learners should be able:
To evaluate the safety, adequacy, and
reliability in terms of quantity and quality of
ground and surface water sources.
To evaluate the adequacy of source water
protection.
To review the key components of water
sources for ground and surface supplies.
To identify the key data required to
determine potential sanitary deficiencies.
To recognize sanitary deficiencies associated
with facilities, operations, maintenance,
management, and contingency planning.
To identify improper well construction and
equipment installation.
To evaluate the adequacy of surface water
intakes and appurtenances.
To evaluate adequacy of spring and roof
catchment facilities, operation, and
maintenance.
To evaluate the adequacy of transmission
facilities.
To determine compliance with federal, state,
and local regulations.
Data Collection
Generally, enough data should be collected so the
inspector can evaluate the safety, adequacy, and
reliability of the water source being surveyed. For
example, raw water quality data aid in evaluating
the safety of the source; high raw turbidity or
coliform counts may indicate problems with source
quality and may aid in regulatory compliance
determination. Information about safe yield and
system demand is important in evaluating the
adequacy of the system to meet the demands for
water placed on it. Data that should be collected
are included in the following narrative and sanitary
survey questions.
Regulations and Standards to
Consider
Most of the regulatory requirements for public
water systems focus on the quality of water
entering the distribution system. However, source
water type and quality are a major part of the
Surface Water Treatment Rule, the Interim
Enhanced Surface Water Treatment Rule and the
Stage 1 Disinfectant/Disinfection By-products
Rule. Compliance with the Ground Water Rule,
Long-Term 1 and Long-Term 2 Enhanced Surface
Water Treatment Rules, and Stage 2 Disinfectant/
Disinfection By-product Rule will also depend on
source quality and type. See Chapter 2 of this
Guide for more information on these rules.
3-1
-------
How to Conduct a Sanitary Survey
Water Sources
Quantity of Water
Importance of Evaluating. The inspector should
evaluate the capability of the system to meet the
demands placed on all of its components. Demands
exceeding available treatment capacity can cause
inadequately treated water to enter the distribution
system. Similarly, inadequate flow or pressure in
the system can result when demand exceeds the
capacity of the source of supply, transmission lines,
pumps, distribution system piping, or storage
facilities. Inadequate flow or pressure affects the
consumers' use of the water supply, hinders fire
fighting capabilities, and creates opportunities for
non-potable liquids to enter the system through
cross-connections. Prolonged interruptions in water
service represent a public health hazard.
Estimating Demand. Most States have guides for
estimating the average daily demand, maximum
daily demand, and probable maximum momentary
demand for various types of establishments (non-
community systems) and community systems.
These guides may be useful for evaluating small
system demands. The values shown may vary
throughout the nation, and the inspector is advised
to review local information on similar water
systems serving similar size establishments and
communities. State and local requirements may
vary. Additional allowance should be made for uses
such as frequent lawn watering, swimming pool
maintenance, industrial and commercial process
water, cooling water, and fire fighting.
It is also very important for the inspector to
recognize the relationship between source water
quantity and storage. For example, when bulk
storage is provided the sources have to be capable
of providing at least the maximum daily demand.
Storage facilities can provide water during periods
of high demand and can fill during periods of low
demand. On the other hand, hydropneumatic tanks
are essentially designed to maintain acceptable
pressures while limiting the cycling of pumps.
Hydropneumatic tanks are the only storage
provided for most very small systems, so the source
and source water pumping must be capable of
meeting the system's much higher maximum
momentary demand. The inspector should be
prepared to make reasonably accurate estimates of
probable water demands for a wide variety of types
and sizes of community and non-community public
water systems.
Sanitary Deficiencies - Quantity
1. What is the total design production
capacity?
Comparing this figure with metered or
estimated demand figures allows the inspector
to determine if source capacity is adequate.
2. What is the present average daily
production?
Comparing this figure with values for other,
similar systems on a per capita basis may point
out problems within the system. An evaluation
of average daily production trends also may
indicate problems. For example, if
consumption is higher than in similarly sized
systems, or if production trends are increasing
without an accompanying population or use
increase, excessive leakage within the
distribution system may be indicated.
3. What is the maximum daily production?
This figure should be compared with the design
capacity of the various major system
components. Operating records from the
maximum demand day can be reviewed to
determine the performance of the source,
treatment, storage, and distribution system
under stressful conditions.
4. Is the safe yield sufficient to meet current
and future demands?
Capital improvements may be necessary if
average daily production approaches or
exceeds the design capacity of major system
components (e.g., the safe yields of the sources
of supply or the raw water pumping and
transmission, treatment, finished water
pumping, storage, and additional sources).
5. Is the quantity of the source adequate?
To answer this question, the inspector should
determine if the source is adequate for current
as well as future demands. The source should
be able to continuously meet the demands of
3-2
-------
Chapter 3 - Water Sources
the water system, the demands of which will
vary based on the system type, size, climatic
conditions, and storage facilities used.
Decreasing trends in quantity are also
important to note. Operating records should
provide this information, but when operating
records are not available the inspector must be
prepared to make reasonable estimates.
6. If permits are required, is the facility
operating within the limits? Are permits
available?
Some States require systems to have operating
permits or to operate within the constraints of
water rights laws. In addition, systems that
discharge waste streams to ground or surface
water may be required to have discharge
permits (e.g., National Pollutant Discharge
Elimination System [NPDES] permits).
7. Does the system have an operational
master meter?
Without an operational and calibrated master
meter, it is difficult for the utility to accurately
monitor production. Some small systems meter
the hours their pumps run. With this
information the inspector can use pump curves
to estimate production.
8. How many service connections are there?
This figure gives the inspector an idea of the
size of the system in terms of number of homes
and businesses served by the system. It should
not include connections for vacant lots.
9. Are service connections metered?
This allows a water balance to be made. There
is also a correlation between metered service
and water conservation. If the system is
metered, the per capita consumption is usually
lower than if the system is not metered.
10. Does the system have interconnections
with neighboring systems or a
contingency plan for water outages?
It is important that the system have a plan to
deal with water outages so it can quickly
correct their causes. Interconnections should be
made with only approved sources. Also,
emergency supplies should be made available
during extended outages or to meet
emergencies.
11. Does the system have redundant sources?
Many States require community water systems
supplied by ground water to have at least two
supply sources in case one is lost.
12. Are there any abandoned, unused, or
auxiliary sources?
Surface supplies that are physically connected
to the water system may contaminate finished
water. Abandoned sources should be physically
disconnected. Abandoned or unused wells
should be sealed properly to prevent
contamination of the aquifer.
Quality of Water
Proximity to Contamination
The likelihood of contamination is increased by the
proximity of the water source to, for example,
sewers, septic tank waste disposal, construction
projects, animal pastures, chemically treated
agricultural land, and chemical storage areas (such
as highway deicing salt or petroleum products).
Other sources of contamination are natural, such as
runoff from high flooding; iron, manganese, or
other chemicals in soil and rock formations; and
decomposing organic matter.
Substances that Alter Quality
Substances that alter the quality of water as it
moves over or below the surface of the earth may
be classified as organic, inorganic, biological, or
radiological.
Sources of Impurities
The impurities in natural waters depend largely on
the circumstances of the source and its history.
Water destined to become ground water picks up
impurities, including possible contaminants, as it
seeps through soil and rock. Potential pollution
sources include leaking sanitary sewers, septic
systems, waste disposal sites, and accidental
discharges. Uptake of minerals by water is
3-3
-------
How to Conduct a Sanitary Survey
common. The natural straining
of water as it moves through soil
and aquifer material can remove
some particulates and, combined
with a relatively long retention
period in the ground, often aids
in removing and inactivating
microorganisms. A long
retention time can, however,
create problems. Purging
contaminated ground water can
require much time and money.
Ground Water
Small Utilities - Main Source.
Ground water is the principal
source of water for small
systems. It is readily available in
most areas of the country in
sufficient quantities to meet the needs of small
water systems. Ground water generally has a more
consistent and better microbiological quality than
surface water, having undergone considerable
natural purification through straining and
prolonged storage. However, a number of ground
water systems have suffered source water
contamination due to improper chemical storage
and waste disposal. Ground water tends to require
little treatment prior to use, while surface water
usually requires rather extensive treatment to
remove or inactivate bacteria, Giardia,
Cryptosporidium, and viruses.
Aquifer Classification. Aquifers are classified as
confined (or artesian) aquifers or unconfined (or
water-table) aquifers. The distinction between the
two is important in terms of the vulnerability of the
aquifer to man-made contamination. In a confined
aquifer, the water is sandwiched between an upper
and a lower layer of impermeable material called
an aquiclude. Clay, the most frequently
encountered aquiclude, forms a natural barrier to
the upward or downward migration of ground
water. This barrier restricts the downward
movement of contaminants from the surface into
the confined aquifer, protecting the wells and
springs that draw water from it. Aquicludes also
restrict migration of contaminants from other
aquifers above or below the confined aquifer.
Because of the protection provided to confined
aquifers, their water is considered to be relatively
invulnerable to contamination.
Aquifer Types
Contamination of Unconfined Aquifers. An
unconfined aquifer rests on an aquiclude and has
no confining layer above it. As a result, percolation
of precipitation and infiltration of surface water
from streams, lakes, and reservoirs carries water
and contaminants from the surface into the aquifer.
Unconfined aquifers are, therefore, considered to
be comparatively vulnerable to contamination.
Confined and Unconfined Aquifers
| CONFINING LAYER J
'CONFINED"AQUIFER"[|
Surface Water
Quality. Because surface water is subject to
contamination by both man and nature, and
because its quality can vary considerably over
time, a relatively high degree of treatment is
required to ensure surface water's safety on a
continuous basis. Surface water treatment is
generally more sophisticated than ground water
3-4
-------
Chapter 3 - Water Sources
treatment, requires more diligent operation and
maintenance, and results in higher costs.
Impoundments. On occasion, a small water
system will rely on surface water as its source
because of the poor quality or lack of local ground
water. Other factors being equal, impoundments
such as natural lakes, ponds, or reservoirs are
preferable to streams because the quality of the
water is usually less variable.
Surface Water Impoundment
Sanitary Deficiencies - Quality
1. Does the system monitor raw water
quality?
Most drinking water regulatory monitoring
requirements relate to treated water, that is
water in the treatment process, at the entry
point to the distribution system, or in the
distribution system. Water systems should have
an appropriate raw water quality monitoring
program to track changes in quality with
particular attention to periods of high runoff,
drought, and other stressful conditions.
2. Is the source adequate in quality?
A review of monitoring records should answer
this question. As with quantity, any trends of
decreasing quality should be noted.
3. Is the system using the highest quality
source available?
Because water quality monitoring and testing
do not measure all potential contaminants, a
system should use the highest quality source
available, based on its knowledge of water
quality and potential sources of contamination.
4. Is there a trend of decreasing raw water
quality that would suggest the need for a
new source or changes in treatment in the
future?
Inspectors should review water quality trends
in raw and finished water to determine if the
system should consider seeking new sources or
adding or changing treatment.
5. Does monitoring of raw water quality
indicate an immediate, significant sanitary
deficiency?
In the case of a ground water source, for
example, does the occurrence of coliform-
positive samples suggest a sanitary defect is in
the well that requires immediate attention.
Source Protection
The inspector should evaluate the system's efforts
to protect its water source. The basic principles of
source protection apply regardless of whether a
system has a ground water supply or surface water
supply. In general, systems should follow these
steps in this evaluation:
I. Select a planning team.
2. Define the wellhead protection area or the
watershed area.
3. Identify actual or potential sources of
contamination in the defined area.
4. Implement measures to control sources of
contamination.
5. Plan for the future and develop a
contingency plan.
During the sanitary survey, the inspector should
determine the adequacy of the system's source
water protection program. Are sufficient resources
being devoted to this effort? Does the system have
an actual program? Is the program active? Was a
program discontinued because the system was
unable to implement important tasks such as
3-5
-------
How to Conduct a Sanitary Survey
identifying or controlling sources of
contamination?
Source Water Protection Map
The SDWA Amendments of 1986 required
states to develop a wellhead protection
program for all public water
system wells. On a
system-specific basis, this
involves delineating the wellhead
protection area, inventorying the
potential sources of
contamination, managing the
wellhead protection area, and
planning for contingencies.
First order stream
Second order stream
Third order stream
Fourth order stream
Watershed outline
Length
Native corporation
owned land
Core Service
owned land
USFS owned land
Road
Railroad
Intalke
Sampling point
Components of a Program.
Measures that can be used to
protect the source include
ownership of the recharge area
and zoning ordinances or
regulations that prohibit certain
land uses within the recharge
area. The inspector should
determine if recharge area
protection, such as a wellhead
protection plan, is in place and
should evaluate its effectiveness.
2. What is the size of the
protected area and who
owns it?
Sanitary Deficiencies - Source
Protection
1. Is the watershed or aquifer-recharge area
protected?
Recharge Zone Activity. What is the nature of
the area? Does the system have a wellhead or
watershed protection program? The nature of
activities in the well's recharge zone or in the
watershed and the degree to which they are
controlled can influence the quality of the
water source. This is especially true if the
aquifer is unconfined.
Wellhead Protection Program. An effective
way for systems to protect well source
recharge areas from contamination is to
develop and implement wellhead protection
(WHP) plans. A system's WHP plan should
follow EPA's effective five-step process for
wellhead protection presented on page 3-5.
To reduce the extent of
contamination of their watersheds, many
utilities have chosen to purchase a portion of
them. Another method is to restrict activities
through zoning and ordinances.
Recharge Area
3-6
-------
Chapter 3 - Water Sources
3. What is the nature of the protection area?
Is the protection area industrial, agricultural,
forest, or residential? As previously noted,
activities in the watershed will affect the water
quality of runoff. The potential for spills from
industrial activities, herbicides and pesticides
from agricultural land uses, organics from
plant decay, and animal-borne diseases are a
few problems associated with land use in a
watershed.
4. How is the area controlled?
This question enables the inspector to evaluate
the effectiveness of watershed control
measures. Ownership with
restricted access is the most
stringent measure, but it is
also the most costly. If
ordinances are used, the
inspector should determine
how they are enforced.
5. Has management had the
area surveyed?
If the utility has had a
survey conducted, the
inspector may be able to
answer many of the above
questions by referring to it.
The fact that a utility has
conducted such a survey
indicates it is concerned
about protecting its water
supplies.
6. Is there an emergency
spill response plan?
Some industries (e.g.,
petroleum) are required to
have emergency spill plans.
The utility should identify
potential spill sites and
develop contingency plans to
deal with any spills.
However, because a plan is
only paper, the utility must
identify the necessary
equipment and personnel. In
addition, coordination
among relevant agencies
(fire, police, water utility) must be worked out
and rehearsed prior to any emergency.
Wells - Specific Sanitary
Deficiencies
Well Components
Many well components cannot be seen. Some of the
more important components are described below.
Casing. A well casing prevents the collapse of the
bore hole, keeps surface and subsurface pollutants
from entering the water source, provides a column
Components of a Drinking Water Well
[WELL VENT I
3-7
-------
How to Conduct a Sanitary Survey
of stored water for positive well pump suction
head, and houses the pump and its discharge pipe.
Grout. Cement or bentonite clay grout is
frequently used during construction to fill the
annular open space left around the outside of the
well casing. This grout prevents surface water and
shallow ground water from entering the well, and it
prevents water from moving between aquifers.
Screens. Screens are installed at a well's intake
point to hold back unstable aquifer material and
permit the free flow of water into the well. The well
screen should be of good quality (e.g., good
structural properties, corrosion resistant, and
hydraulically efficient). Where formation
conditions are suitable, many small systems use
perforated or slotted casings in lieu of screens.
Sanitary Seal. Wellhead covers or seals at the top
of the casing or pipe sleeve connections prevent
contaminated water and other material from
entering the well. Several types of covers and seals
are available to meet the variety of conditions
encountered, but the principles and objectives of
allowing free movement of air while excluding
contamination are the same.
Pitless Units. Pitless adapters eliminate the need
for a well pit. A well pit to house the pumping
equipment or allow access to the top of the well
casing is not recommended because the pits can
flood, introduce pollution hazards, and present
confined space entry risks. Some states prohibit the
use of pits. A pitless adapter generally includes a
special fitting designed for placement on the side of
the well casing. The well discharge piping is
screw-threaded into the fitting, providing a tight
seal. The pitless system allows the well piping to
be connected to the casing underground below frost
depth and, at the same time, provides good
accessibility to the well pump and drop pipe for
repairs without excavation.
Sanitary Deficiencies Related to
Wells1
1. Is the well in a confined or unconfined
aquifer?
This information is important in evaluating the
source's vulnerability to contamination. The
name of the aquifer and its type can usually be
obtained from the operator or from well
drilling records. Well logs made during well
drilling can indicate whether there is one or
more confining layers above the well screen.
' The student may want to consider viewing the
NETA video Sanitary Survey Inspection; Before
You Begin . . . WELLS prior to reading this section.
Lineshaft Turbine
Submersible Turbine
3-8
-------
Chapter 3 - Water Sources
The presence of significant thicknesses of clay
material indicates that a confining layer
separates the well screen from the ground
surface and, therefore, the well is likely to be in
Pitless Adapters
SANITARY WELL COVER
(VENTED)
H SUBMERSIBLE CABLE |
CONDUIT""]!
CEMENT GROUT
FORMATION SEAL
a confined aquifer. The log also includes
additional useful information.
Other sources of information about the type of
aquifer a well is in includes the state's
geological survey agency and the U.S.
Geological Survey. These agencies frequently
maintain reports on wells and aquifers across
the state.
2. Is the site subject to flooding?
Surface water should be kept from entering a
well. Runoff in the immediate area should be
drained away from the well site. At the least,
any openings in the well casing should be
located at least 3 feet above the 1 percent
chance (i.e., 100-year) flood elevation.
Flood Insurance Rate Maps (FIRMs) can be
obtained from the Federal Emergency
Management Agency's National Flood
Insurance Program. FIRMs show the base
flood elevation in a given area. Information on
flooding and site drainage may be obtained
from the owner/operator, visual inspection, and
flood-stage records. Any openings in the well
casing should be located at least 3 feet above
the the 100-year flood elevation.
3. Is the well located near any immediate or
potential sources of pollution?
The appropriate state regulatory agency should
be consulted for its policy concerning well
location, particularly the minimum protective
distances between the well and sources of
existing or potential pollution. The table on the
next page provides examples of typical
minimum distances. These distances are based
on general experience and are not guarantees of
freedom from contamination. The table makes
no distinction between unconfined and confined
aquifers, although confined aquifers are
typically much better protected. The water
purveyor should provide even greater
protection where possible. The table applies to
properly constructed wells with the protective
casing set to a depth of at least 20 feet below
the ground surface. Other types of wells
require special considerations.
3-9
-------
How to Conduct a Sanitary Survey
Sample Minimum Distances
Between Wells and Pollution
Sources
Source
Feet from Well Remarks
Watertight Sewers
Other Sewers
Septic Tanks
Sewage Field, Bed, or Pit
Animal Pens and Yards
50 Consult the
100 state regulatory
100 agency for
200 special local
200 requirements.
Source: Small Water Systems Serving the Public, Chapter 5.
Sample Minimum Distances from
Well to Pollution Sources
%
Look for Other Sources. During the field
inspection, inspectors should also be alert for
potential sources of contamination other than
those listed above. Fuel and chemical storage
facilities and transmission lines are important
sources to evaluate. Pollution from these
sources can travel much farther than pollution
from the sources in the table and illustration
above. On-site water treatment chemical
storage and fuel tanks should be investigated as
well as off-site sources. Also, spills and
highway runoff that contain petroleum
products or deicing salt can contaminate
shallower wells nearby.
Potential Contamination Sources
4. How Deep Is the Well?
The greater the depth of the aquifer used, the
less chance there is that surface contamination
will degrade water quality. Deeper aquifers
generally have a more consistent quality of
water.
5. Is drawdown measured?
Drawdown is the difference between static
water levels and pumping water levels.
Measuring drawdown is important because
changes in static water level or drawdown can
indicate problems in the aquifer (declining
water levels) or pump. Such changes also can
indicate well encrustation. The operator should
be regularly measuring drawdown and
recording the results.
6. What is the depth of the casing?
The casing must be strong enough to resist the
pressures exerted by the surrounding formation
and corrosion by soil and water environments.
The casing must be long enough to provide a
channel from the aquifer to the surface through
unstable formations and through zones of
actual or potential contamination. The casing
should extend above potential levels of
flooding and should be protected from flood
water contamination and damage. In
unconsolidated soils, the casing should extend
3-10
-------
Chapter 3 - Water Sources
at least 5 feet (1.5 meters)
below the estimated
maximum expected
drawdown level. In
consolidated rock
formations, the casing
should extend 5 feet into
firm bedrock and be sealed
into place. The system
should be able to provide
this information.
7. What is the depth of
grouting?
Specific grouting
requirements for a well
depend on surface conditions, especially the
location of pollution sources, and subsurface
geologic and hydrologic conditions. To achieve
the desired protection against contamination,
the annular space must be sealed to whatever
depth is necessary, but in no case less than 20
feet.
8. Does the casing extend at least 18 inches
above the floor or ground?
This provides protection against surface runoff
or drainage problems. Eighteen inches is
recommended when there is no potential for
flooding.
9. Is the well properly sealed?
Wellhead covers or sanitary seals at the top of
the casing or pipe sleeve connections prevent
contaminated water and other material from
entering the well. Well covers and pump
platforms should be elevated above the
adjacent finished ground level and sloped to
drain away from the well casing.
10. Does the well vent terminate 18 inches
above the ground or floor, or 3 feet above
maximum flood level with return bend
facing downward and screened?
This is necessary to keep water (from
water-cooled bearings, for example), dust,
insects, and animals out of the well casing.
Typical Lineshaft Turbine Installation
11. Does the well have a suitable smooth-
nozzle raw-water sampling tap?
This is important when raw water samples
need to be collected. A threaded tap can
introduce contaminants.
12. Are check valves, blow-off valves, and
water meters maintained and operated
properly?
Valves should be maintained and operated to
prevent contaminants from entering the well.
13. Is the upper termination of the well
protected?
The upper termination of the well should be
either housed or fenced to protect it from
vandalism and vehicle damage. The area
should be sloped away from the well to prevent
surface water from draining toward the casing.
14. Is lightning protection provided?
Lightning surges can develop in power lines
during thunderstorms. Such surges can damage
pump motors, resulting in loss of water supply
and costly repairs. To protect against this,
lightning arresters can be installed where
electrical service lines are connected to service
entrance cables, or at the motor control box.
Multi-ground arrangements can be used to
protect the entire pump and well against
damage.
3-11
-------
How to Conduct a Sanitary Survey
15. Is the pump intake located below
maximum drawdown?
Locating the pump intake below maximum
drawdown prevents the pump from running dry
and protects against the pumping of
contamination from upper portions of the water
table.
16. Are foot valves and check valves
accessible for cleaning?
As with above-ground valves, these valves
must be maintained in an operating manner to
prevent the backflow of distribution system
water into the well.
Surface Sources - Sanitary
Deficiencies
Special Considerations
Surface sources used by small water supply
systems require consideration of additional factors
not usually associated with ground water sources.
When small streams, open ponds, lakes, or open
reservoirs are used as sources of water supply, the
danger of contamination and spread of intestinal
diseases such as cholera, typhoid fever,
cryptosporidiosis, giardiasis and dysentery are
generally increased. Clear water is not always safe,
and the old saying that running water purifies itself
to drinking water quality within a stated distance is
not true.
Unsafe Unless Treated
The physical, chemical, and bacteriological
contamination of surface water make it necessary
to regard such sources of supply as unsafe for
domestic use unless reliable treatment, including
filtration and disinfection, is provided. The
treatment of surface water to ensure a constant,
safe supply requires diligent attention to operation
and maintenance by the owner of the system.
Principal sources of surface water that may be
developed are controlled catchments, ponds or
lakes, surface streams, and irrigation canals.
Except for irrigation canals, where flows depend on
irrigation activity, these sources derive water from
direct precipitation over the drainage area.
Value and Use
The value of a pond or lake as a source is its
ability to store water during wet periods for use
during periods of little or no percipitation. A pond
should be capable of storing at least 1 year's
supply of water. It must be of sufficient capacity to
meet water supply demands during periods of low
rainfall with an additional allowance for seepage
and evaporation losses. The drainage area
(watershed) should be large enough to catch
enough water to fill the pond or lake during wet
seasons.
Reduce Contamination
To minimize the possibility of chance
contamination, the watershed should be:
A fenced area that is clean and has
controlled vegetation.
Free from barns, septic tanks, privies, and
soil absorption fields.
Protected from erosion and drainage from
livestock areas.
Reservoirs
Reservoirs such as dam impoundments offer
several advantages:
Raw water reserve.
Settling.
Best quality raw water with multiple
intakes.
Streams and Rivers
Impact on Treatment
Streams that receive runoff from large uncontrolled
watersheds may be the only sources of water
supply. The physical, chemical, and bacteriological
quality of surface water varies and may impose
unusually or abnormally high loads on the
treatment facilities.
3-12
-------
Chapter 3 - Water Sources
In-stream Drop Inlet Location
Intake Location
Stream intakes should be located upstream from
wastewater discharges, storm drains, and other
sources of contamination. If possible, water should
be pumped when the silt load is low. A low-water
stage usually means that the temperature of the
water is higher than normal and the water is of
poorest chemical quality. Maximum silt loads,
however, occur during maximum runoff.
High-water stages shortly after storms are usually
the most favorable for diverting or pumping water
to storage. These conditions vary and should be
considered for the particular stream. Obviously,
many systems have no raw water storage facilities
and have to meet daily demands with run-of-the-
river water quality.
Infiltration Galleries
Use and Location
Recreational or other developments in the
mountains may have access to a headwater
mountain stream where the watershed is generally
heavily forested and uninhabited by human beings.
After periods of heavy rainfall or spring thaws,
however, debris and turbidity may cause problems
at the water intake and will materially increase the
required degree of treatment. If the conditions are
suitable, this problem can be avoided by
constructing the intake in an underground chamber
(infiltration gallery) along the shore of the stream
or lake.
Use with Streams and
Lakes
Galleries may be considered
where porous soil formations
adjoin a stream or lake so that
the water can be intercepted
underground to take advantage
of natural filtration. Any gallery
access structures should be
located above the level of severe
flooding.
Components
A typical installation generally
involves the construction of an
under-drained, sand filter trench
parallel to the stream bed and about 10 feet from
the high-water mark. The sand filter is usually
located in a trench at least 30 inches wide and
about 10 feet deep, sufficient to intercept the water
table. At the bottom of the trench, perforated or
open joint tile is laid in a bed of gravel about 12
inches thick, with about 4 inches of graded gravel
over the tile to support the sand. The embedded tile
is covered with at least 24 inches of clean, coarse
sand, and the remainder of the trench is backfilled
with fairly impervious material. The collection tile
drains to a watertight, concrete chamber from
which water may flow to the distribution system by
gravity or pump, whichever is appropriate.
Example of an Infiltration Gallery
3-13
-------
How to Conduct a Sanitary Survey
Chlorination is required for all surface water
sources and adequate contact time must be
provided to meet the requirements of the Surface
Water Treatment Rule (SWTR). Filtration is also
required of all surface water systems that are
unable to meet the SWTR's criteria for avoiding
filtration.
Modified Gallery
Where soil formations adjoining a stream are
unfavorable for the location of an infiltration
gallery, the debris and turbidity occasionally
encountered in a mountain stream may be
controlled by constructing a modified infiltration
gallery in the stream bed.
Using a Dam
If there is no natural pool in the stream bed, a dam
is usually constructed across the stream to form a
pool. The filter is installed in the pool by laying
perforated pipe in a bed of graded gravel, which is
then covered by at least 24 inches of clean, coarse
sand. About 24 inches of free board should be
allowed between the surface of the sand and the
surface water level. The collection lines may
terminate in a watertight, concrete basin located
adjacent to the upstream face of the dam from
which the water is diverted to chlorination and
treatment facilities.
Ranney Well Collector
Ranney well collectors are located in the flood
plain to draw water from a river bed water table.
Transmission Lines
Raw-water transmission lines occasionally serve
customers on the way to the treatment plant. In
such instances, point-of-entry or point-of-use
treatment must be provided to ensure adequate
protection of public health and compliance with the
SWTR's requirements.
Sanitary Deficiencies Related to
Surface Sources
1. Is any treatment provided in the reservoir?
The addition of any chemicals to the reservoir
should be noted. Of particular concern is
Ranney Well
JW
i^^
~^**-^l;
ensuring that only approved chemicals are
used, that they are properly applied, and that
there are no discharges of treated water that
will cause violations of the Clean Water Act.
2. Is the area around the intake restricted for
a radius of 200 feet?
Restricting contact sports (e.g., swimming and
water skiing) and the use of power boats near
the intake is important. These restrictions will
help reduce the coliform and organic pollution
of the intake water.
3. Are there any pollution sources near the
intakes?
Sources of pollution such as wastewater
discharges, feed lots, marinas, and boat-
launching ramps should be identified. If the use
of the reservoir is not restricted, the impacts of
these activities should be minimized as much
as possible by keeping them away from the
intakes.
3-14
-------
Chapter 3 - Water Sources
4. Are multiple intakes at different levels
used?
Because of fluctuating water surface elevation
and variable water quality, intakes must be
provided at different depths. Seasonal turnover
of the reservoir, algae blooms, and thermal
stratification can cause water quality problems.
These concerns apply to deep reservoirs.
Streams and shallow reservoirs generally are
not subject to stratification.
5. Is the highest quality water being drawn?
The operator should perform monitoring tests
to determine the water quality at various depths
in order to draw the best quality water. The
operator should be asked how the intake level
is selected, what tests are performed, and at
what frequency. Suggested tests are algae
counts, dissolved oxygen, metals, and nitrogen
values.
6. How often are intakes inspected?
As with all components, maintenance must be
periodically performed on the intake structure.
Removal of debris and inspection of intake
screen integrity will prevent damage to piping
valves and pumps. This is particularly
important during winter due to the danger of
ice buildup.
7. What conditions cause fluctuations in
water quality?
Conditions such as stratification, algae blooms,
ice formation, on-shore winds, and changing
currents may adversely change water quality.
Conditions creating such problems should be
noted, along with the measures taken to
mitigate them.
8. Has the dam been inspected for safety (if
applicable)?
Dams should be routinely inspected to avoid
conditions that may endanger their integrity.
Many states require such inspections. If
inspections are not required, operators should
be encouraged to look for such things as
erosion, sinkholes, burrowing animals, and
trees growing in the dam face.
Springs - Specific Sanitary
Deficiencies
Capture Ground Water
To properly develop a spring as a source of supply,
the natural flow of ground water must be captured
below the ground surface in a way that does not
contaminate the water. Springs are subject to
contamination by wastewater disposal systems,
animal wastes, and surface drainage. They are also
susceptible to seasonal flow variations, and their
yield may be reduced by the pumping of nearby
wells.
Types of Springs
Springs may be gravity or artesian. Gravity
springs occur where a water-bearing stratum
overlays an impermeable stratum and outcrops to
the surface. The water permeates at the point where
the impermeable stratum outcrops. They also occur
where the ground surface intersects the water table.
This type of spring is particularly sensitive to
seasonal fluctuations in ground water storage and
frequently dwindles or disappears during dry
periods. Gravity springs are characteristically low-
yielding sources, but when properly developed they
may be satisfactory for small water systems.
Artesian springs discharge from openings in the
confining layers of artesian aquifers. They may
occur where the confining formation over the
artesian aquifer is ruptured by a fault. Artesian
springs are usually more dependable than gravity
springs, but they are particularly sensitive to the
pumping of wells developed in the same aquifer. As
a consequence, artesian springs may be dried up by
nearby well pumping.
Criteria for Selection
Important criteria for spring sources include
selection of a spring with acceptable water quality,
development to the required quantity of water, and
sanitary protection of the spring collection system.
The measures taken to develop a spring must be
tailored to the prevailing geological conditions.
Spring Source Collection System
Perforated Pipe. Spring flow is intercepted by a
system of perforated pipes driven into the
water-bearing stratum or laid in gravel-packed
3-15
-------
How to Conduct a Sanitary Survey
trenches. The flow is directed into a storage tank.
As an alternative, a watertight concrete collection
chamber is constructed with openings in the
bottom, a side wall, or both to intercept the flow.
This chamber may also serve as the storage tank.
Where possible, the walls of the collection chamber
should extend to bedrock or to the impervious
stratum. The watertight walls should extend at least
2 feet above the finished ground to prevent surface
Example of a Spring Collection System
water from entering. An overlapping (shoe-box)
cover will prevent the entrance of debris.
Spring Box. The spring box is usually constructed
in place out of reinforced concrete. It is designed to
intercept as much of the spring as possible. When a
spring is located on a hillside, the downhill wall
and sides are extended downward to bedrock or
impervious soil to ensure that the structure will
hold back water to maintain the desired level in the
chamber. Supplementary cutoff walls of concrete
or impermeable clay may be used to assist in
controlling the water table near the tank. The lower
portion of the uphill wall of the tank must have an
open construction to allow water to move in freely
while the aquifer material is held back. Back filling
with graded gravel helps restrict the movement of
aquifer material.
At the completion of construction the area around
the spring box should be covered with an
impermeable material (clay or membrane). It
should be sloped away to prevent surface water
from entering the collection system.
The Spring Box Cover. The spring box cover
should be cast in place to ensure a good fit. Is
should be of a "shoe box" type framed at least 4
inches, and preferably 6 inches, above the surface
of the roof at the manhole opening. The opening
should be fitted with a hinged,
lockable, watertight cover that
extends down the frame at least
2 inches. When the spring box is
covered, the manhole should be
elevated 24 to 36 inches above
the covering sod.
Drain Pipe. A drain pipe with
an exterior valve should be
placed close to a wall of the
spring box at the floor level to
allow draining. The end of the
pipe should extend far enough to
allow free discharge to the
ground surface, away from the
spring box. The discharge end of
the pipe should be screened to
prevent nesting by animals and
insects.
Overflow. The overflow is
usually placed slightly below the
maximum water level elevation.
The overflow should be screened and have free
discharge to a drain apron of rock to prevent soil
erosion at the point of overflow.
Intake to System. The supply intake should be
located about 6 inches above the floor and should
be screened. Care should be taken to ensure good
bond between pipes and the concrete structure.
Sanitary Deficiencies Related to
Springs
1. Is the recharge area protected?
Activities in the recharge area and the decree to
which they are controlled can affect the quality
of the water source.
3-16
-------
Chapter 3 - Water Sources
2. What is the nature of the recharge area?
Is it industrial, agricultural, forested, or
residential? Different types of activities
potentially subject the water source to
pollutants from land uses, spills, and runoff.
3. Is the site subject to flooding?
The introduction of surface water into a spring
should be avoided and runoff should be drained
away from the spring.
4. Is the supply intake adequate?
The supply intake should be screened and
located 6 inches above the chamber floor in
order to reduce the withdrawal of sludge that
may build up in the chamber.
5. Is the site adequately protected?
The following precautionary measures will
help ensure spring water of consistently high
quality:
A surface drainage ditch should be located
uphill from the source to intercept surface
water runoff and carry it away from the
source. Springs close to agriculturally
developed land treated by pesticides and
herbicides may be particularly susceptible to
contamination.
Site fencing, locked covers, and warning
signs should be used to provide protection
from stray livestock and from tampering.
6. Is the spring box properly constructed?
The spring box should be watertight to prevent
the inflow of undesirable water. The spring box
cover should be overlapping, impervious, and
lockable. The drain should have an exterior
valve, and the exterior end should be screened.
The overflow should have a downward turned,
screened free discharge to a drain apron to
prevent soil erosion. This information may be
obtained by inspecting the spring box.
7. What conditions cause changes to the
quality of the water?
A marked increase in turbidity or flow after a
rainstorm is a good indication that surface
runoff is reaching the spring.
Roof Catchments
It is a common practice in various locations to use
roof catchments to collect rain water. While the
quality and quantity of rain water may be
questionable at times, it may be the only reliable
source of water available to a small community or
an individual. The quality of water is affected by
the type of roofing material, its age, and the
amount of debris collected on the roof.
Collection
Rain water is collected in a roof gutter and directed
to one or more downspouts. The flow is directed
into a storage tank.
Diversion Box
The first water that runs off the roof usually
contains the maximum amount of debris and bird
droppings. This material is prevented from flowing
into the storage tank by the diversion box.
The Tank
The tank is usually constructed of plastic, concrete,
wood, or metal.
The Tank Cover
The tank's manhole cover should be cast in place to
ensure a good fit. Is should be of a "shoe box" type
framed at least 4 inches, and preferably 6 inches,
above the surface of the roof at the manhole
opening. The opening should be fitted with a
hinged, lockable, watertight cover that extends
down the frame at least 2 inches.
Drainpipe
A drainpipe with an exterior valve should be placed
close to a wall of the tank at the floor level to
permit draining. The end of the pipe should extend
far enough to allow free discharge to the ground
surface, away from the tank. The discharge end of
3-17
-------
How to Conduct a Sanitary Survey
Roof Catchment Collection System
the pipe should be screened to prevent nesting by
animals and insects.
Overflow
The overflow is usually placed slightly below the
maximum water level elevation. It should be
screened and have free discharge to a drain apron
of rock to prevent erosion at the overflow point.
Intake to System
The supply intake should be located about 6 inches
above the floor and should be screened. Care
should be taken to ensure a good bond between
pipes and the concrete structure.
Sanitary Deficiencies Related to
Roof Catchments
1. What is the condition of the roof?
Old roofs, especially roofs made of galvanized
metal, can contribute to high concentrations of
contaminants.
2. Is there a diversion box?
This is a key to reducing contamination.
3. What is the condition of
the gutter system?
The gutters should be in
good repair and protected
from excessive debris.
4. Is the collection chamber
properly constructed?
The tank cover should be
lockable. The drain should
have an exterior valve, and
the exterior end should be
screened. The overflow
should have a downward
turned, screened free
discharge to a drain apron to
prevent soil erosion. This
information may be obtained
by inspecting the collection
chamber.
5. Is the supply intake adequate?
The supply intake should be located 6 inches
above the chamber floor and screened. This
location reduces the withdrawal of the sludge
that may build up in the chamber. In addition,
the roof area and gutter system must be sized
to allow an adequate collection of water. The
collection quantity is based on rainfall
frequency and amount, roof area, and gutter
capacity.
6. Is the roof catchment system cross-
connected to another public water
system?
Many homes and apartment buildings that have
roof catchment systems are also connected to
the distribution system of a public water
system. In these cases the public water system
should always be provided with backflow
protection.
3-18
-------
Chapter 3 - Water Sources
Transmission - Specific Sanitary
Deficiencies
Importance of Transmission
Transmission of raw water from the source of
supply to the treatment facility is a vital component
of a public water supply system. Transmission
facilities from the treatment plant to the
distribution system are equally important.
Deficiencies
A bypass around a treatment plant by a
transmission line, for example, is an important
sanitary deficiency that could allow raw water to
enter the distribution system. During a sanitary
survey the inspector should evaluate the ability of
transmission facilities to provide an adequate and
continuous supply of safe drinking water.
Sanitary Deficiencies -
Transmission System
1. Are transmission facilities in place that
can bypass a treatment plant?
The inspector should carefully evaluate piping
in and around the treatment plant to ensure that
the plant is not being bypassed. Closed valves
are insufficient to prevent raw water from
bypassing treatment. It is not uncommon for
bypasses to be installed during construction
and then not removed when the plant is brought
on line.
2. Are there any customers on the raw water
transmission lines?
Customers who use water from the raw water
transmission lines are not receiving potable
water. They should be disconnected or
provided with appropriate treatment.
3. What are the age and condition of the
transmission lines?
Old transmission lines may be subject to
catastrophic failures that could result in a
water system being completely without water.
The inspector should evaluate the potential for
such failures.
4. Are there redundant transmission
facilities?
Would failure of a single transmission line
leave a system without water? The inspector
should evaluate this potential and recommend
additional transmission lines if needed.
5. Are transmission lines vulnerable to
disasters or terrorism?
Transmission lines in earthquake-prone areas
or that cross streams or rivers are subject to
failures that could render the water system
without an adequate supply of water.
Inspectors should evaluate how disaster-proof
a facility is and how the system would respond
to a potential disaster.
Transmission lines are also points at which
contaminants could be deliberately injected in
an effort to affect a large portion of the service
population.
3-19
-------
Water Supply
Pumps and
Pumping Facilities
Pumps and pumping facilities are essential, yet
vulnerable, components in nearly all water systems.
Improper design, operation, or maintenance of
pump systems can pose serious sanitary
deficiencies, including a complete loss of the water
supply. To assess the safety, adequacy, and
reliability of the entire water system, the inspector
must include water supply pumps and pumping
facilities as an integral part of the sanitary survey.
Learning Objectives
By the end of this chapter, learners will be able:
To list the regulatory standards that apply
and key data required to conduct a sanitary
survey of a pumping facility.
To identify various types of water supply
pumps, their appropriate uses, and their
associated components.
To recognize sanitary deficiencies and
serious safety hazards associated with
physical facilities including the pumping
station, pumping equipment, appurtenances,
and stand-by power systems.
To recognize sanitary deficiencies and
serious safety hazards associated with
procedures and practices including
management, operations, and maintenance
of the pumping facilities.
To determine if a pumping
adequate, and reliable.
facility is safe,
Data Collection
If available in the files at the inspector's office, the
following data should be reviewed prior to
conducting the on-site inspection of a pumping
facility:
Operating records provided by the water
utility.
The utility's construction, operation, and
maintenance specifications.
If this information is not available in advance, it
should be collected during the inspection. Once in
the field, during the initial interview with the
operator, the inspector should develop a list of the
pumps in the system to Ensure that they all are
evaluated during the sanitary survey.
Regulations and Standards to
Consider
Prior to the inspection, the following regulations
should be reviewed and considered by the inspector
as part of the sanitary survey:
State design standards for pumping systems
ANSI/NSF standards 60 and 61
Chapter 2 of this Guide
Water Supply Pumps and Pumping
Facilities
Basic Information
Introduction. There are several types of pumps
and applications in water systems. Pumps that are
used to transport water through the system are
either "variable displacement" or "centrifugal"
pumps. Other applications such as chemical feed,
4-1
-------
How to Conduct a Sanitary Survey
sludge removal, sampling, and air compression
require "positive displacement" pumps. This
chapter covers the prime movers of water. The
other pumping applications are addressed in
subsequent chapters.
During the sanitary survey, the inspector must be
able to identify pumps by type to assess whether
they are being used appropriately. Each category of
pump has its own operating characteristics and
appropriate set of applications. There are multiple
types of pumps in each category.
Variable Displacement Pumps,
Applications, and Components
Variable Displacement Described. Variable
displacement pumps are used in high-volume
applications where an even flow rate is required
(e.g., transporting water through the treatment and
distribution systems). Their discharge rate varies
with the head (i.e., as the lift or head increases, the
pump output decreases). These pumps are not self
priming. Consequently, they depend on a positive
suction head, or an air-tight seal on the intake side
of the pump if the level of the water to be pumped
is below the pump impeller. The most common
class of variable displacement pump is the
centrifugal pump.
Centrifugal Pump. A centrifugal pump has a
rotating impeller mounted on a shaft turned by the
power source. The rotating impeller increases the
velocity of the water and discharges it into a
surrounding casing (volute) designed to slow its
flow and
convert the
Centrifugal Pump velocity to
pressure.
Centrifugal
pumps
equipped with
one impeller
are classified
as single-stage
and pumps
containing two
/~\r* rv»/~\r-£»
^>i HIV^AV^
impellers are
classified as
multi-stage. Multi-stage pumps are capable of
pumping against greater discharge heads, but do
not increase the volume of flow.
Applications in a Water System. Several types of
centrifugal pumps are used in water systems for a
wide variety of applications. The most common
applications are:
Well pumps (vertical turbine and
submersible).
Gas chlorine system and vacuum booster
pumps.
Backwash water pumps.
Raw water pumps.
Finished water pumps (high lift).
Booster pumps in distribution system.
Horizontal - Close Coupled
BEARINGS
Horizontal - Split Case
4-2
-------
Chapter 4 - Pumps and Pumping Facilities
Submersibile Turbine
Lineshaft Turbine
[DISCHARGE HEAD]
___,
ELECTRICAL
CONNECTION ^^~ij I H DROP PIPE I
DRIVING SHAFT I
Sanitary Deficiencies for the
Pumping Station and Well House.
The inspector should evaluate the facilities that
house pumping systems. These facilities include
well houses, booster stations, and raw and finished
water pumping stations. The questions that the
inspector should ask include the following:
1. Is security adequate?
Pumping facilities should be protected against
vandalism and unauthorized entry. The
perimeter of the property should be fenced in
and the building's doors and windows should
be locked. Check around the outside of the
building for electrical panels, switches, and
valves. Make sure that they cannot be accessed
by the public. Also, drain and vent openings in
the building should be screened to prevent
animals from entering.
2. Are the building and equipment protected
from flooding?
The pumping station should be at least 3 feet
above the highest flood level, and surface
runoff should drain away from it. Pumping
stations should have adequate drains to protect
the pumping equipment from flooding if a pipe
breaks inside the facility. Compartments that
are below grade, such as wet wells and dry
pits, should be sealed to prevent the entry of
undesirable water, either through the walls or
from surface runoff. Dry pits should include a
sump and sump pump. Check to make sure that
electrical controls and motors are not subject to
flooding.
3. What is the structural condition of the
building?
Check the condition of the walls, roof,
windows, and doors to make sure that rain
cannot enter the building. Concrete floors and
masonry walls should be checked for cracks.
Cracks around pump piping indicate water
hammer conditions when pumps are started and
stopped. This can result in pressure surges that
cause breaks in the distribution system.
4-3
-------
How to Conduct a Sanitary Survey
Pumping Station/Well House
4. Are heating, ventilation, and lighting
adequate?
Where appropriate, the building should be
heated to prevent pipes from freezing.
Ventilation should be provided in all climates
to reduce heat, moisture, and corrosion. The
interior of-the building should have permanent
lighting to facilitate inspections and
maintenance at night.
5. Can equipment be accessed and removed
from the building for maintenance?
Check to see that there is access to the
equipment for inspection and maintenance. In
addition, there should be a way to remove large
equipment from the building. For example, a
well house should have a removable access
hatch in the roof directly over the well. This
will make it easier to use a crane to remove
mechanical equipment.
6. Is the building orderly and clean?
The order and cleanliness of the pumping
facility should be observed. Dirt can combine
with lubricants and reduce bearing life. Also,
dirt and moisture will form an insulating
coating on motor windings and can cause the
motor to burn out. Poor housekeeping is in
most cases a sign of poor operation and
maintenance (O&M). Do not,
however, automatically assume
that an orderly and clean room
indicates good O&M practices
are followed.
7. Is the pumping station
also used for storage?
The pumping equipment room
should not be used to store
hazardous, flammable, or
corrosive materials. Chemicals
(including water treatment
chemicals such as chlorine,
hypochlorite, fluoride, and
sodium hydroxide) should be
stored in and fed from a room
that is separate from the
pumping equipment and
electrical controls. (For more
information on chemical feed
and storage, see Chapter 6, Water Treatment
Processes.)
8. Is safety equipment adequate?
Check to see that the water system has
identified all confined spaces and they are
properly vented. The operator should activate
the vent fans and test the atmosphere prior to
entry. All OSHA confined-space entry
procedures should be followed. Access
ladders should be firmly anchored. Each
pumping station should be equipped with a fire
extinguisher that, at a minimum, is rated for
class B (flammable liquids) and class C
(electrical equipment) fires.
4-4
-------
Chapter 4 - Pumps and Pumping Facilities
Sanitary Deficiencies
for Pumping
Equipment and
Appurtenances
As the inspector, you should
evaluate the pumping equipment
and appurtenances. This includes
pumps, motors, drives, valves,
piping, meters, gauges, electrical
controls, and alarm systems.
Pumps and Motors
1.
2.
Lineshaft Turbine Pump Station
What are the number
(including reserves),
location, and type of
pumps?
There should be at least two
equal pumping units for each
applicationexcept in the
case of well pumps where
another complete well system provides suitable
back-up. The system may use pumps for
various reasons, and type of pump should be
matched to the application. For example,
centrifugal (variable displacement) pumps
should not be used to feed liquid chemicals
when precise delivery is required against a
variable head. Talking to the operator and
reviewing plant schematics can provide this
information.
18 hours. A review of pump system operating
records should provide this information.
3. When and how are pump capacities
determined?
The inspector should determine the results of
any pump tests and when each pump was last
rated. The inspector should also verify that the
Is the actual capacity of
the pumping facility
adequate to meet the
demand?
Pumps should have ample
capacity to supply enough
water to meet peak demands.
The required reserve
capacity for pumps may
vary from state to state, but
a rule of thumb for a water
supply/multiple unit/constant
speed pump application is:
With the largest pump out of
service, the average daily
demand should be supplied
by the remaining available
pumps within a maximum
combined pumping time of
Booster Pump Station
T
jti
4-5
-------
How to Conduct a Sanitary Survey
Submersible Turbine Pumping Station
Lineshaft Turbine Pumping Station
4-6
-------
Chapter 4 - Pumps and Pumping Facilities
method used was correct. This is particularly
important when elapsed-time meters (pumping
time) are used to estimate water production.
For example, 10 years ago the pump may have
operated at an average of 8 hours per day. Now
the same pump averages 12 hours per day. The
question is: Is the increase in running time due
to an increase in water demand or a change in
operational strategy, or has pump output
capacity been reduced because of an increase
in operating head or mechanical wear? This
can be verified only with a functioning flow
meter and pressure gauge and suitable
operating records. Upon reviewing pump
testing and operating records, the inspector
should determine if duplicate pumps are
equally productive.
4. What is the condition of the equipment?
All units operable? All pumps should be
operable. A serious sanitary deficiency exists,
for example, if only one of two raw water
pumps is functional. The inspector should
inquire about the strategy by which pumps are
operated. Ask how often backup units are
exercised. If there will be no disruption to the
operation, the inspector should ask the operator
to run each unit, one at a time, to observe it.
While each pump is operating, the inspector
should examine the state of repair by looking
and listening for excessive noise, vibration,
heat, odors, and leaking water or lubricant.
The inspector should also look for signs of
moisture and dirt around motor cooling inlets.
Excessive noise, vibration, heat or odors?
While running, the pump and motor should
have a smooth sound and should not be
excessively hot. Excessive noise, vibration, and
heat indicate serious problems such as bearing
failure, shaft misalignment, pump cavitation,
impeller wear, or motor breakdown. Heat and
the smell of ozone or burning insulation can
indicate many problems including motor
winding failure, poor power supply, excessive
current draw, loose connections, and motor
control system deficiencies. Any one of the
items cited above is an indicator that immediate
maintenance is required.
Leaking water? A pump stuffing box requires
a constant drip of water through the packing
gland, not an excessive spray. Leaking water
can produce moisture around the motor, unsafe
conditions around the pump room, and a
pathway for contaminants to enter the water
supply if vacuum conditions occur at the
stuffing box when the pump is shut down.
Dirt and grime? The inspector should look for
signs of dirt around the motor cooling fins and
air intake ports. Dirt and grime can inhibit the
flow of air necessary to cool the motor
windings.
Leaking lubricant? Pumps and motors should
not be over lubricated because bearing failure
and motor burnout can result. Signs of
improper or excessive lubrication are grease
pushing out of bearing seals and grease or oil
accumulating around the pump and motor.
5. Are the correct types of lubricant used?
ANSI/NSF-approved lubricants should be used
where contact is made with the water supply
(i.e., stuffing box, oil-lubricated well shaft
bearings, check valves). It is not necessary to
use ANSI/NSF-approved lubricants on
components that do not come into direct
contact with the water supply (i.e., motor
bearings, shaft, and external pump bearings).
All luBrtcants should be used according to the
manufacturer's recommendations.
6. Are the frequency and amount of
lubrication adequate?
The inspector should observe the level and
appearance of oil in pump and motor lubricant
reservoirs to determine if adequate attention is
being paid to lubrication. Oil that has a milky
appearance has become contaminated with
moisture. In the case of well pumps, the type
and amount of lubrication are particularly
important. Some vertical turbine pumping
systems are designed with oil-lubricated shaft
bearings. If the sealing tube surrounding one of
these bearings fails, oil will enter the water
supply. The inspector should find out how
much oil is added regularly by the operator and
compare this to the amount used when the
equipment was new. A significant increase in
oil addition is a sure sign of a broken seal.
An indication that greased bearings are not
being lubricated properly is unbroken painted
4-7
-------
How to Conduct a Sanitary Survey
surfaces covering the grease fittings and exit
port plugs. A schedule for lubrication should
be part of a preventive maintenance program.
Appurtenances
1. Are the pumping systems equipped with:
Check valves? On centrifugal pump systems,
each pump should have an operating check
valve. When observing the operation of each
pumping unit during the sanitary survey, the
inspector
should
pay Swing Check Valve
particular
attention
to the
check
valve
during the
start-up
and shut-
down
periods.
The check valve should not slam open or shut.
If it does, pressure surge or water hammer
conditions could be occurring in the
distribution system, resulting in breaks in the
mains or service lines. When the pump is not
running, the drive shaft should not spin
backwards. Backspin is an indicator that the
check valve is not functioning and, in some
cases, could lead to the impeller actually
spinning off of the drive shaft.
Isolation valves? Each
pump should have an
isolation valve on the
discharge line. In systems
where the intake water level
is above the pump impeller
(an application known as
"flooded suction" or
"suction head"), an isolation
valve is also required on the
intake side of each pump.
Isolation valves facilitate
removing the pump for
main-tenance. Simply
because a valve is present
does not mean that it is
working. The inspector
O Y&S
Gate
Valve
Turbine Flow Meter
should ask the operator how frequently the
valves are exercised and should request the
opening and closing of one or more isolation
valves.
Pressure gauges? Each pump should have a
discharge pressure gauge so that actual
operating head conditions can be measured. A
pressure gauge and flow meter are critical for
determining pump capacity and detecting
changes in operating conditions. In addition to
a discharge pressure gauge, distribution system
booster pumps should also be equipped with
compound gauges on the intake side of the
pumps. Compound gauges measure positive
and negative pressures. The pressure on the
intake side of distribution booster pumps
should not be allowed to fall below 20 psi
because lower pressures can cause backflow
problems in the distribution system upstream
of the booster pump.
Flow meter? The inspector should note if the
pump is metered and if the meter is functioning
properly.
Besides
providing
a more
accurate
accounting
of water
being
pumped, a
meter can
help the
operator
detect
changes in the system and take corrective
action before a serious problem develops. Flow
meters should be equipped with totalizers to
record the total amount of water pumped over
a given time period.
Blow-offline? Pumping systems, especially
well pumps and raw water pumping systems,
should be fitted with isolation valves and
piping to direct the discharge to the open air
and not into the water supply line. Blow-off
lines facilitate flushing the immediate water
source and testing the pump.
Air/vacuum relief valve? To prevent air from
entering the distribution system at startup and
to prevent vacuum and possible collapse of the
4-8
-------
Chapter 4 - Pumps and Pumping Facilities
Prelube for Water Lubricated
Bearings
SOLENOID VALVE |
Air/Vacuum Release Discharge
Line
AIR VACUUM RELEASE
| SILENT CHECK
Raw Water Pump Seal Water
System
CROSS-CONNECTION CONTROL
FOR SEAL WATER
Prime Line - Suction Lift Pump
CONCENTRIC REDUCER t- \ L£
;; ' ^^. r
FOOT VALVEV g
ECCENTRIC REDUCER I
column pipe during shutdown, well pumping
systems should be equipped with a foot valve
(submersible well pumps) or air/vacuum relief
units (vertical turbine well pumps). The
inspector should determine whether the relief
valve closes properly following startup and
opens properly following shutdown. The
discharge pipe on the relief valve should be
turned downward, screened, and terminated
with a suitable air-gap.
Lineshaft Turbine with
Air Release Valve
: AIR VACUUM RELEASE]
r
I CONTROL VALVE |
4-9
-------
How to Conduct a Sanitary Survey
2. Are there any cross connections present?
Cross connections can be found in:
Water lubricated bearing systems
Pump seal water lubrication systems
Air/vacuum release discharge lines
Priming lines for suction-lift pumps
In each case, if the source water for these
systems is treated water, the potential for
backflow exists. These systems must be
adequately protected with an air-gap or
approved backflow prevention device. A
thorough description of cross-connections and
examples are provided in Chapter 8.
Controls
1. Is the motor control system adequately
designed and reliable?
Automatic systems are widely used to control
pumping cycles. The inspector should evaluate
the control system and determine if it is
suitable for the application, if it is functioning
properly, and if it is equipped with resets and a
manual override switch. Pumps that supply
water to the distribution system should be
controlled automatically based on the pressure
in the system. An example of unsuitable
application of a control system is finished
water pumps that are controlled by time clocks
alone. In this case, the pumps would not supply
additional water if demand is unusually high,
for example if a main breaks or firefighters
must tie into a hydrant. This could result in
low pressure or a total loss of supply. The
inspector should ask the operator how
frequently, if ever, he or she resets the motor
controls or operates the pumps manually in
order to maintain the system pressure.
A hydropneumatic system typically uses a
simple pressure switch to cycle pumps off and
on. The inspector should check to see that the
system is operating properly and should make
sure there is no shut-off valve between the
pressure switch and the pump. If a valve is
closed between the pressure switch and the
pump, the system will call for water and the
pump will become damaged by pumping
against a closed valve.
2. Is the pump system equipped with an
adequate failure alarm system?
The pump control system should be equipped
with failure alarms. If the pump fails to start,
or stops for any reason other than normal shut-
down on the automatic cycle, an alarm system
should activate to notify the operator that the
system has failed. The type of alarm should
also be considered. Many pumping stations are
equipped with a flashing light or a horn
situated outside the building and activated
when the system fails. This type of alarm
depends on someone actually seeing the light or
hearing the horn and calling the water system
operator. It is not, of course, fool proof. A
more dependable alarm system is one
connected to a telephone line and programmed
to automatically dial a series of telephone
numbers until the problem is corrected.
3. Does the auxiliary equipment have fail-
safe devices?
The control sequence for equipment that
operates in conjunction with the main pump
and motor should be evaluated. For example,
the electrical supply to a chemical feeder that
activates automatically with the water pump
motor should be equipped with an automatic
shut-down device in case the pump fails to
produce
water for
any
reason.
This can
be done by
installing
a "low-
flow" or
"low-
pressure"
cut-out
switch
between
the pump
and the
check
valve. This device must sense water flow or
pressure in order to energize the chemical
feeder. The absence of such a device has in
many cases led to a significant overfeed of
chemical.
Low-Flow Switch
4-10
-------
Chapter 4 - Pumps and Pumping Facilities
4. Are controls equipped with elapsed time
meters (ETMs)?
Motor control systems should be equipped with
an ETM for each pump. An ETM is similar to
an automobile odometer and registers the
cumulative running time of the pump motors.
This information can be used by the operator to
schedule maintenance, estimate pump output,
and compare duty cycles and efficiency of
equal pumping units.
5. Are controls adequately protected?
The inspector should take note of the general
condition of the control devices and check that
the equipment is enclosed in protective
cabinets. Control enclosures that are outside
buildings should be closed tightly and have a
NEMA 4X rating (weatherproof). Control
switches such as hand, off, or automatic
switches, disconnects, and resets should not be
accessible to the public.
6. Are control systems adequately
maintained?
The control systems should be included in the
water system's preventive maintenance
program. Maintenance of these systems
requires a particular expertise in industrial
controls. The operator should be thoroughly
trained in this area, or should have an expert
available to respond to system malfunctions.
Safety
1. Do rotating and electrical equipment have
protective guards?
The inspector should be concerned with safety
as well as with the sanitary aspects of the
equipment. Check to see that belts, gears,
rotating shafts, and electrical wiring are
properly shielded to prevent injury.
[Note: While conducting the sanitary survey,
the inspector should not wear loose clothing
or a necktie.]
Sanitary Deficiencies - Auxiliary
Power
The inspector should evaluate the need for
auxiliary power and, if provided, should evaluate
the design, condition, and O&M of auxiliary power
units (APUs).
1. Is auxiliary power needed and, if so, is it
provided?
Auxiliary power may be necessary for the
continuous operation of a water system. It is
especially critical if outages are frequent or if a
system has limited capacity for storing finished
water. The inspector should ascertain the
frequency and duration of previous power
outages and what effect power outages have
had on the water supply. State design
guidelines should also be consulted when
determining the need for auxiliary power.
2. What type of auxiliary power is provided
and how is it activated?
Emergency power may be provided by an
auxiliary generator that is driven by diesel or
gasoline engines, or by engines that are directly
connected to the pump drive shaft by a right-
angle drive mechanism. Activation of the APU
should be automatic upon the loss of primary
power. There should be an "automatic transfer
switch" that will transfer the current load to the
auxiliary power unit. Upon loss of power, the
operator should not be required to manually
start the APU and transfer the load, although
the system should allow manual operation.
3. Does the auxiliary power unit supply ALL
electrical systems at the pumping station?
In addition to the pump motor, the APU should
operate all electrical functions in the pumping
station, including lights, heat, ventilation,
automatic controls, andmost importantany
chemical feed systems that are connected. This
is a problem with mechanically driven (right-
angle drive) type systems operate only the
pump during primary-power outages;
consequently, untreated or partially treated
water is pumped to the distribution system.
4-11
-------
How to Conduct a Sanitary Survey
4. Where is the fuel tank located?
Is the fuel tank for the APU buried
underground? If so, is there a risk of fuel
leaking into the water supply? If the fuel tank
is above ground, it should be mounted inside a
spill containment vessel.
Auxiliary Power
5. Is the auxiliary power unit exercised and
tested regularly and properly?
The inspector should ascertain how and how
often the APU is exercised and tested. The
system should be exercised at least once a
week, with an operator in attendance. If the
APU is exercised automatically without an
operator in attendance, there is no way to
monitor the system's performance and no way
to detect small problems before
they escalate. Furthermore, these
systems should be exercised
under a load. The APU should
be used as the source of power
for the pumping facility during
the exercise period. This
procedure ensures that all
functions of the APU are tested
and working properly. Records
should be kept of APU
exercising, and these records
should include engine and
generator gauge readings.
POWER
OFF
GENERATOR
RIGHT ANGLE GEAR DRIVE
6. Is the auxiliary power unit
secure and maintained in
good condition?
The inspector should check to
see that the APU is included in
the preventive maintenance
program. Regular maintenance
should be performed according
to the manufacturer's
recommendations. The inspector
should visually check the general
condition of the unit for signs of
leaking fluids or lubricants. If
the APU is outside, it should be
enclosed. Vent openings and
openings around piping should
be screened to prevent the
entrance of animals. The APU
should not be accessible to the
public.
7. Are there any cross-
connections between the
auxiliary power system
and potable water?
Some APU engines use potable
water for cooling. The inspector
4-12
-------
Chapter 4 - Pumps and Pumping Facilities
should determine how the engine is cooled. If
potable water is used, the coolant should not
return to the potable system, and the
connection between the water supply and the
engine should be protected by an air-gap or
approved backflow-prevention device.
Sanitary Deficiencies - Operation
and Maintenance
Equipment-specific O&M concerns were addressed
previously in this chapter. During the sanitary
survey, the inspector should also assess the overall
O&M approach as it relates to the pumping
systems from a programmatic standpoint.
1. Are the number and skill level of the staff
adequate for operating and maintaining
the pumping facilities?
The management and operations staff should
be assessed according to the recommendations
provided in Chapter 10. Individuals who are
responsible for maintaining pumping systems
should be trained in troubleshooting them and
in maintaining electrical and mechanical
systems. If no one on the staff is competent in
these areas, maintenance should be performed
by contractors.
2. Are adequate operational records
maintained for pumping facilities?
The system should maintain, at a minimum, the
following operating records for each pumping
unit:
Suction and discharge pressures
Operating hours
Flow meter readings
Amperage and voltage readings.
3. Are written standard operating procedures
available and followed?
Written operational instructions should be
provided so that all operators follow the same
procedures. This may be as complex as a
comprehensive operations manual, or as simple
as a one-page list of instructions. Written
procedures should cover items such as daily
operations and inspections (including a
checklist), start-up and shutdown procedures,
and responses to equipment failure and other
emergencies. They should include contingency
plans).
4. Is there an established and documented
preventive maintenance (PM) program?
Improper maintenance can lead to system
failures and sanitary deficiencies. A written
PM program should be established and
followed for each piece of equipment in the
pumping facility. The programs should be
based on manufacturers' recommended
maintenance tasks, and records should be kept
of maintenance as it is performed. In general,
smaller water systems need much less
sophisticated PM programs, however, all water
systems should have a program in place, even
if it is very basic. The inspector should
determine if specific components of a PM
program exist and ask to see PM records.
Critical components of a PM program include:
Equipment Inventory: A record that
includes data plate information such as
model and serial numbers, manufacturer's
ratings, and performance specifications.
Manufacturers' Technical Literature:
Provided with new equipment by its
manufacturer, this includes O&M
specifications, schematics, and spare parts
lists.
Written PM Tasks and Schedule: A
written list of PM tasks (from the O&M
manuals), a schedule, and instructions for
performing these tasks. This can be part of a
computer program, or in smaller systems,
can simply be recorded on index cards.
Records of Maintenance Performed: In
small systems, this can be recorded on index
cards. The inspector should look for recent
dates and make spot comparisons to the task
schedule.
List of Technical Resources: This should
include manufacturers' representatives for
service and parts, local specialists for
instrumentation maintenance, electrical and
mechanical repair specialists, and
construction contractors.
4-13
-------
Storage Facilities
Finished water storage facilities play a vital role in
providing a safe, adequate, and reliable supply of
water. Schools, hospitals, nursing homes, factories,
and home owners all depend on a consistent,
dependable supply of safe water. Failure to
maintain the structural and sanitary integrity of
storage facilities can lead directly to the loss of
property, illness, and death.
Learning Objectives
Identify key data needed regarding design,
maintenance, and operation of storage
facilities in order to determine their
adequacy and reliability.
Review the major components of ground,
elevated, and hydropneumatic finished water
storage facilities.
Evaluate operator safety practices and
equipment in relationship to storage
facilities.
Recognize sanitary deficiencies related to
the capacity, physical condition, and
operation of storage systems such as
inadequate volume or pressure,
contamination by animals and insects,
corrosion, metal fatigue, and vandalism.
Data Collection
To evaluate water storage for sanitary deficiencies,
the inspector should gather the following
information:
Type and volume of the storage facilities.
The results of the last inspection.
Maximum and minimum pressures at high
and low elevations in the system.
Maximum and minimum pressures in each
pressure zone.
Documentation of state approval for
changes to or installation of the tanks.
Number of pressure zones are the system.
Verification of the presence of a hydraulic
model of the system.
The type of chlorine residual testing method
being used.
Regulations and Standards to
Consider
The inspector should consider and review the
following information prior to inspection:
40 CFR 1926.146 - Confined space entry.
The American Water Works Association
(AWWA) standard for the type of piping
materials used in the system.
AWWA C-652-92 - Disinfection of water
storage facilities.
System construction standards.
'The student may want to consider viewing the video entitled Sanitary Survey Inspection; Before You
Begin . . . STORAGE FACILITIES prior to reading this section. To order, see www.epa.gov/safewater/
dwa/orderform.pdf.
5-1
-------
How to Conduct a Sanitary Survey
State construction standards.
Storage Facilities
Basic Information
Purpose of Storage. The purpose of storage is to
ensure that safe water is always available for
normal situations and emergencies.
Clearwell. Finished water storage often begins at
the treatment facility in a structure known as a
clearwell. Outside the distribution system, storage
tanks are normally elevated on steel legs or built on
hills to provide water pressure. A very small
system will often use a pressurized tank known as
a hydropneumatic tank to provide pressure and
limit the cycling frequency of pumps.
Adequate Volume and Pressure. Water systems
must be able to provide safe water at all times at
adequate volumes with sufficient pressure
(normally not less than 35 psi at any point in the
system). Low pressure, inadequate volumes, and
contaminated water from storage facilities are a
result of poor design, construction, operation or
maintenance.
Varying Demand for Water. Demand for water in
a distribution system changes significantly
throughout each day. As it varies, a properly
operated finished water storage facility acts as a
reserve, or buffer, which prevents sudden changes
Example of Water Use
System Population
Average daily per capita usage
800 persons
100 gallons
800 x 100 = 80,000 gallons per day, Average
Daily Demand (ADD)
100,000 gallon elevated storage (tower)
Two pumps supply the system and fill the tower
Pump #1
Pump #2
85 gpm
120 gpm
122,400 gpd
172,800 gpd
Note: gpm = gallons per minute; gpd = gallons
per day
in water pressure in the system. Below is an
example of varying water demands during one day.
An average daily demand of 80,000 gallons per day
equals 56 gpm. However, an average gpm is very
misleading. As shown in the table below, the
demand varies greatly between the low at 3 a.m.
and the high during a small house fire at 3 p.m.
Time of
Day
3 a.m.
7 a.m.
3 p.m.
Average
Demand
Low
Showers, Dishes
House Fire
Demand
30 gpm
56 gpm
750 - 1,000 gpm
Pumps Alone Insufficient. Although either pump
is capable of pumping the required 80,000 gpd
based on 24 hours, neither is capable of keeping up
with the day's peak demands. The water stored in
the tower makes up the difference. In addition, the
demand for water varies from day to day and from
one season to the next.
Clearwell
Clearwells are often in-ground tanks from which
water is pumped to storage and distribution after
treatment including disinfection. The effectiveness
of chemical disinfectants, such as chlorine, depends
on the concentration of the disinfectant and the
contact time the organisms are exposed to the
disinfectant. Contact time (CT)is usually achieved
Clearwell
5-2
-------
Chapter 5 - Storage Facilities
in the clearwell, often with baffling, to ensure
adequate CT (CT in mg-min./L = contact time in
minutes X disinfectant residual in mg/L). See
Chapter 6 for a more complete explanation of CT.
Gravity Storage
[Note: Many of the following items apply to
clearwells as well as to storage in the
distribution system. Gravity storage facilities
(tanks) must be elevated to maintain sufficient
pressure to all customers within the service area.
This elevation may be accomplished by
mounting the tank on structural supports above
ground or by erecting the tank on a hill.]
Gravity Storage
Large-Diameter Tanks Preferred. When gravity
storage is used, the pressure at the head of the
distribution system fluctuates with the water level
in the tank. Shallow, large-diameter storage tanks
are preferred over deep, small-diameter tanks
because the larger diameter tanks have more water
per foot of drawdown and are thus less prone to
pressure fluctuations.
Prefabricated standpipes and elevated tanks are
readily available in a wide range of capacities.
Prestressed concrete tanks are common for ground
level and underground applications; they are quite
popular because they require less maintenance than
steel tanks.
Components. In addition to the basic tank, storage
facilities (for both elevated tanks and clearwells)
include some or all of the following components:
Cover or Roof. Keeps out rain and foreign
matter (e.g., birds, bird droppings, leaves).
The roof and sidewalls must not have any
gap where they join.
Air Vent (screened). Gravity tanks must
"breathe" as the tank is filled and emptied.
A plugged vent can result in structural
damage to the tank from either a vacuum or
an excess pressure condition. A screen is
essential to keep out birds, bugs, and
mammals.
Note: A globe-shaped device known as a
"finial ball," which is a combination vent
and roof ladder support, was popular on old
riveted tanks and generally was constructed
without any kind of protection from rain,
birds, or bugs. These vents and others that
are poorly designed should be replaced or
modified in a manner that accommodates air
movement while protecting water quality.
Overflow Pipe (screened). Prevents
excessive pressure and structural damage to
the tank and distribution system if supply
Shallow Tanks with Large
Diameters are Preferred
Materials. Storage tanks are most commonly
constructed of steel or reinforced concrete.
Tank Components
5-3
-------
How to Conduct a Sanitary Survey
pumps fail to shut off. A screen or a close-
fitting flapper gate is required on the
overflow to keep out birds, bugs, and
mammals.
Inlet and Outlet Piping. Connects to the
distribution system for filling and
discharging the tank.
Drain Pipe. Empties the storage facility (not
into the distribution system).
Isolation Valve. Isolates the tank from the
distribution system.
Access Hatch. Facilitates inspection and
maintenance of the tank.
Cathodic Protection Plate. Provides access
to cathodic protection rods.
Ladders and Walkways. Facilitate
inspection and maintenance of interior and
exterior. Internal catwalks should have a
solid floor with raised edges to keep dirt out
of the water.
Fence Enclosure. Provides security and
safety.
Staff Gauge with Float. Measures water
level in the tank.
Ultrasonic Sensor. Measures water level in
the tank.
Pressure Gauge. Measures head pressure.
The head pressure can be used to calculate
the level of water in the tank.
Control System. Maintains water levels in
the tank.
Altitude Valve. Prevents a tank at a lower
elevation from overflowing while allowing a
tank at a higher elevation to fill.
Valve Pit. Contains altitude valve, isolation
valve, and drain valves.
Alarm System. Detects unacceptable low
and high water levels and sends signal to
operators.
Advantages of Gravity Storage
A gravity storage system offers several advantages
over other (e.g., hydropneumatic) systems:
Greater flexibility to meet peak demands
with less variation in pressure.
Storage for fire-fighting use.
One to five days of storage to meet needs.
Use of lower capacity wells (well not
required to meet peak demand by itself).
Sizing of pumps to take better advantage of
electric load factors (able to pump during
discount hours).
Reduced on-and-off cycling of pumps.
Storage Filling Requirements. When gravity
storage is employed, it is recommended that the
pumping system be capable of supplying the
average daily demand (ADD) in 18 hours without
the use of the largest pump. Using our previous
example:
ADD: 80,000 gallons per day
Large Pump: 120 gpm (not part of determination)
Small Pump: 85 gpm (91,800 gallons in 18 hours)
Two Methods of Filling and Using Storage.
Water supplies may pump directly to a gravity
storage tank from which water flows on demand to
the points of use. This method is called direct
pumping. It can be designed to provide chlorine
contact time for disinfection.
Direct Pumping
ISOLATION VALVE I
I jHED WATER INLE1
5-4
-------
Chapter 5 - Storage Facilities
Water may also be pumped into the distribution
system several miles from the tank, with the tank
riding or floating on the system.
Tank Floating on the System
i it-
INLET/OUTLET LINE |
__
[ALTITUDE VALVE I
Sanitary Deficiencies for Gravity
Storage
1. Is the storage system designed for direct
pumping or floating on the distribution
system?
Direct pumping systems offer an advantage
over floating systems in that the storage tank
provides additional chlorine contact time.
Direct pumping systems tend to have higher
fluctuations in head pressure than floating
systems. In floating systems, treated water is
sent directly to the customer through the
distribution system. A sanitary risk is
presented if disinfection at the treatment
facility is inadequate.
2. Is the storage capacity adequate?
The total storage capacity for gravity storage
systems should be equal to one to five days of
average daily demand. There should be reserve
capacity in the storage tank to allow for
extreme conditions such as power outages in
which case the pumps would be unavailable
unless standby power is supplied. Utilities that
lack adequate storage run the risk of losing
system pressure.
3. Is the storage over-designed?
Conversely, storage facilities that are extremely
over-designed run the risk of producing water
that has objectionable taste and odors. Chlorine
residuals can be lost by failing to use and
replace water on a regular basis, and
disinfection byproducts can be produced if
water is kept in storage for a long time. In
addition, ice buildup can be a threat to the
tank.
4. Is the pumping capacity adequate?
The pumping capacity must be designed to
supply water for both normal peak demand and
potential fire demand while preventing the
excessive loss of head pressure in the tank.
(Most small systems are not designed to meet
fire demands.)
5. Is the elevation of the tank sufficient to
maintain distribution pressure throughout
the system?
The water tank should be sized properly and
located sufficiently above the distribution
system to produce minimum operating
pressures of 35 psi (about 81 feet of head);
operating pressures of 40-60 psi (92 to 139
feet of head) are preferred.
6. Is there a need for separate pressure
zones?
Pressures should not be allowed to exceed 100
psi (231 feet of head). In communities that
have varying topography, customers in the
higher elevations could experience low water
pressure if the gravity storage system is not
designed with separate pressure zones.
The inspector must not assume that because
storage capacity is well designed it is actually
being used. During the sanitary survey, the
inspector should evaluate the operational
strategy of the storage system.
7. Does the operator understand the controls
that regulate tank water levels?
The operator should understand the functions
of the water level control systems and should
be capable of making minor adjustments. There
should be a record that documents the control
pressures and elevation for each phase of the
pumping cycle, including the pressures at
which the alarms are activated.
5-5
-------
How to Conduct a Sanitary Survey
The operator of a system that has altitude
valves and multiple tanks must be capable of
taking pressure and water-level readings and
adjusting the valves to control tank levels.
8. Are there adequate minimum rise and fall
distances?
To maintain an adequate volume of water and
an even distribution system pressure, the
supply pump automatic controls should keep to
a minimum the distance the water inside the
tank rises and falls. The rise and fall should be
sufficient, however, to prevent excessive pump
cycles during hours of peak usage. The water
in the tank should be allowed to rise as close as
possible to the overflow pipe before the supply
pumps stop. The maximum water level,
however, should not be so close to the overflow
pipe that overflows actually occur during
automatic operation.
9. Are control systems reliable and properly
protected?
Determine if the controls are suitable for the
application and are functioning properly. Each
storage facility should be equipped with a
manual override and an alarm system to warn
of pump failures and low water levels. The
inspector should note the general condition of
the control devices and wiring. Check to see
that they are adequately protected from
lightning and other outside elements.
10. Is the water level indicator accurate?
Every storage tank should have a reliable
means of measuring the water level. If properly
maintained, a float and staff gauge is the most
reliable level indicator.
Pressure gauges are acceptable for determining
the water level, but occasional visual checks
should be made inside the tank to verify the
pressure gauge accuracy. (NOTE: 1 psi = 2.31
ft; 1 ft. = 0.433 psi.)
11, Is there a maintenance program?
Maintaining control systems requires particular
expertise in industrial controls. The operator
should be thoroughly trained in this area, or
should have an expert readily available to
respond in case of a system malfunction.
Direct Contamination Concerns
The inspection items below are extremely
important to the health and well being of everyone
in the water system.
1. Is all treated water storage covered?
Finished-water storage tanks must be covered
to prevent airborne contamination, e.g., from
birds, insects, mammals, and algae. Covers
must be watertight, made of permanent
material, and constructed to drain freely and
prevent contaminants from entering the stored
water. The surface of the storage tank cover
should not be used for any purpose that may
result in contamination of the stored water. The
roof-to-sidewall joint must be sealed.
2. Are overflow pipes:
Terminated 12 to 24 inches above a splash
pad?
All overflows and drain lines from a storage
facility should discharge freely into a drainage
inlet structure or onto a splash pad. When a
drainage structure is not available, the splash
pad should be designed to prevent erosion and
undermining of the tank supports or
foundation. The discharge pipe should
terminate 12 to 24 inches above the inlet
structure or splash pad. Overflows must never
be plumbed directly to any sewer or storm line.
Screened?
All overflow pipes should have removable #24
mesh screens to prevent the entrance of birds,
insects, rodents, and contaminating materials.
3. Are air vents:
Turned down or covered to protect the
tank's contents from rain?
Roof vents should terminate in a downward
inverted U or have a cover to exclude rain and
wind-blown debris. They must be designed to
exclude birds and animals and should exclude
5-6
-------
Chapter 5 - Storage Facilities
4.
5.
insects and dust as much as possible consistent
with effective venting. Finial ball designs and
venting through open areas between the roof
and sidewall are of particular concern.
Terminated at a minimum of three pipe
diameters above the surface of storage
tank roof?
A properly constructed vent terminates three
pipe diameters above the roof, which helps to
prevent dried bird droppings from being
inhaled or blown into the vent. For ground-
level structures, the vent should terminate in an
inverted U with the opening 24 to 36 inches
above the roof or sod.
Screened?
A #4 mesh screen will prevent birds from
entering the tank, but this large mesh screen
will not keep out insects, feathers, pieces of
grass, and other foreign material. A #24 mesh
screen is necessary to control insects. Fine-
mesh screens can become clogged, and clogged
vents have led to imploded tanks. While fine-
mesh screens are necessary to keep the water
clean, they must be designed to "give way," or
fail, to protect the tank from collapsing if a
vacuum occurs.
Are the cathodic protection access plates
watertight?
Access plates that are not sealed to a watertight
condition allow bird droppings to wash directly
into the drinking water.
Is the top access hatch designed correctly
and does it close tight?
The hatch opening should have raised side
walls not less than 4 inches tall. The lid or
cover should drop down over the side walls at
least 2 inches. The lid must seal tight to
prevent dust, dried bird droppings, and feathers
from being inhaled or blown into the hatch
opening. Improperly fitted hatch covers are a
common problem, but many can be made
acceptable with minor modifications.
6. Are access hatches locked?
Access hatches should be closed with a solid
watertight cover and a sturdy locking device. It
is not unusual for the wind to lift open an
unlocked cover. Padlocks are often cut off and
individuals then swim or throw things in the
storage facilities.
7. Is there a roof penetration for a water level
indicator cable?
This penetration for the cable allows bird
droppings to wash into the storage facility
unless it is covered and designed to cause rain
water to flow away from the cable opening.
8. Are there other roof penetrations?
Roof penetrations for water lines, chlorine
lines, and electrical devices are all
opportunities for contamination if they are not
kept watertight.
9. Are there sewer lines within 50 feet of an
in-ground storage tank?
Any sewer lines within 50 feet of a storage
facility, such as a clearwell with a floor below
ground level, should be constructed of extra-
heavy or service-weight cast iron pipe with
tested, watertight joints. No sewer lines should
be closer than 10 feet to the tank.
10. Are there cracks in the walls or covers of
the in-ground concrete storage tanks?
Cracks in the tank can allow ground or surface
water into the tank.
11. Is there protection from flooding?
If the drain line is likely to be submerged by
flood water, a watertight blind flange should be
provided to prevent backflow of contaminated
water into the storage facility. All storage
facilities should be protected against flood
waters. The structure and its related parts
should be watertight. The ground above an
underground tank should be graded to drain
surface water away from the tank and to
prevent surface water from pooling near it.
Underground drainage should discharge away
from the structure.
5-7
-------
How to Conduct a Sanitary Survey
12. Can the tank be isolated from the system?
A utility should be able to take its tanks out of
service for inspection and maintenance without
shutting down the entire system. This can
usually be accomplished if gate valves and a
drain pipe have been provided. The operator
should exercise valves regularly to ensure their
integrity.
13. Is the site protected against vandalism?
The storage site should be fenced and locked to
prevent unauthorized entry. Ladders to the tops
of storage tanks should terminate 10 feet above
the ground to deter unauthorized climbing.
Many ladders have a section that "telescopes"
up into the cage. In such cases, the ladder and
access hatch to the ladder cage should be
locked.
14. Are the interior surface coatings
approved?
Coatings that are in contact with water should
be approved by the National Sanitation
Foundation (NSF). Unapproved coatings can
create problems due to organic and inorganic
contamination of stored water.
Coatings should be applied to a water tank by
certified professionals and in accordance with
AWWA Standard D 102-78: Painting Steel
Water Storage Tanks.
15. Are volatile organic chemicals (VOCs)
sampled after painting?
Whenever a tank is painted, the proper curing
time should be allowed. Before the tank is
placed back into service, the tank should be
flushed, disinfected, and filled with water.
Samples should be taken and analyzed for
coliform and VOCs.
[Note: Causes of coating failure. Coatings
can fail for several reasons, including
improper surface preparation, application,
and curing; use of the wrong t}'pe of coating;
removal by ice or other environmental
exposure; and lack of maintenance.]
The rise and fall of water in the tank can affect
corrosion. Exposed metal surfaces that are
submerged and then exposed to air (oxygen)
will corrode at an increased rate. Cathodic
protection (corrosion control devices) may be
provided for metal storage tanks. These devices
should be inspected and maintained annually
by factory-authorized service representatives.
16. Is the tank protected against icing?
When temperatures fall below zero for several
days, ice may form in underground and
elevated storage tanks. In underground tanks,
ice formation is usually limited to surface ice.
In elevated tanks, icing may be more severe;
thick accumulations on sidewalls have been
observed. Serious damage to walls and
structures may result. Tanks have blown their
tops due to the pressures that result; in less
severe cases, the cathodic protection and tank
interiors may be damaged.
Tanks should not be allowed to remain idle if
freezing is a problem. Heaters, circulators, or
bubblers may need to be used in tanks.
Insulation around standpipes should be
provided in very cold climates.
17. Are there indications that the tank may not
be structurally sound?
The inspector should base the answer to this
question on visual observation of washouts,
signs of foundation failure, cracking or
spalding concrete, tank leakage, buckling of
steel, slack in support rods, corrosion, and
signs of other problems.
18. Is the tank protected against corrosion?
The inspector should determine the corrosivity
of the water. The system should take steps
during water treatment to correct for corrosive
properties. Corrosive water can seriously
damage a steel storage tank if the protective
coating is not completely intact.
19. What is the frequency of general
inspection and cleaning?
Storage tanks should be on the operator's daily
inspection list. During the daily visits, the
operator should check the water level in the
tank (with a visual indicator or pressure
gauge), the functioning of the controls, the
5-8
-------
Chapter 5 - Storage Facilities
condition of the overflow pipe, and security.
For facilities with easy access to the roof, the
vent and hatch should also be inspected. The
exterior and interior of the tank should be
inspected annually by qualified personnel.
20. How and how often are the storage tank's
structure and coating inspected?
In addition to the annual inspection, a thorough
structural and coating inspection should be
carried out approximately every 5 years. This
inspection should be performed by personnel
certified by the National Association of
Corrosion Engineers (NACE) and done
according to AWWA D101-53: Inspecting and
Repairing Steel Water Tanks, Standpipes,
Reservoirs, and Elevated Tanks for Water
Storage.
21. Are storage tanks disinfected following
interior maintenance?
Reservoirs and elevated tanks on the
distribution system must be disinfected before
being put into service and after extensive
repairs or cleaning.
Disinfection should be done according to
AWWA C652-92: Disinfection of Water
Storage Facilities.
22. Are there procedures to sustain the water
supply when the storage tank is out of
service for maintenance?
Prior to removing the tank from service for
maintenance, the water utility staff should
coordinate and practice procedures for
sustaining the distribution system pressure.
This can be relatively simple in systems that
are equipped with adequate back-up storage
facilities. A small system that has only one
storage tank or limited reserve storage would
require a more complex means of maintaining
the water supply. This could include operating
high-service pumps manually and positioning
fire hydrant relief valves at various locations
within the distribution system.
Temporary measures should be established,
tested, and practiced thoroughly before the
storage tank is actually removed from service
for maintenance. All water system customers
and the fire department should be notified well
in advance so that conservation and alternative
plans can be made to decrease stress on the
water system. When necessary, high-
consumption customers should be notified and
asked to conserve voluntarily.
23. Are emergency procedures established?
The inspector should learn about the procedure
to detect and respond to low tank levels (low
pressure) and determine if the program is
adequate. A resource list should be available
that contains information on where to obtain
essential storage repair materials and services
in the event of an emergency. An alternative
source of water should be available.
24. Are safety precautions followed?
There are climbing and atmospheric hazards
associated with water storage tanks. Ladders
should be in good condition and secure. The
inspector should determine whether safety gear
is available for climbing and for entry into
confined spaces.
25. If the tank is wooden, is it operated in a
manner to minimize an increase in
bacterial count?
The most effective operating method for a
wooden reservoir includes maintaining a
chlorine residual of at least 1 mg/L, varying
the water level in the tank a few feet each day,
and never allowing the same water to stand in
the tank longer than a few days.
Basic Information -
Hydropneumatic Tanks
Hydropneumatic systems to maintain distribution
system pressure are very common in small water
systems (fewer than 150 living units). They are not
considered adequate for fire fighting, however, and
provide only enough storage to prevent excess
cycling of the pumps. These systems combine the
energy from a pump with the principle of
compressed air pressure to force water into the
distribution system. Understanding how the
hydropneumatic system is susceptible to sanitary
risk requires an understanding of basic system
operation and the role of system components.
5-9
-------
How to Conduct a Sanitary Survey
How They Operate
The system operates in the
following manner:
The water supply pump
starts when the pressure
drops to a predetermined
level (cut-in pressure).
The pumped water
compresses and
pressurizes a pocket of air
(air volume) at the top of
the pressure tank.
Hydropneumatic Tank System
with Air Compressor
When the pressure builds
to a predetermined level (cut-out pressure),
the pump stops and the compressed air
expands as it forces the water into the
distribution system in response to system
demand.
of air-to-water ratio, generally one-third air
to two-thirds water.
Pressure Gauges. Monitor pressure,
generally a 100 psi gauge.
When the pressure falls to
the "pump-on" level
(often 35 to 40 psi), the
pump starts again, and the
cycle repeats. The cycle
rate is the number of
times the pump starts and
stops in 1 hour and varies
based on the system
demand.
Components
A typical hydropneumatic
system is made up of the
following parts:
Steel Tank. Stores water.
Air Volume Control.
Regulates air volume in
the tank.
Relief Valve. Prevents
excessively high pressure.
Inlet and Outlet Piping.
Allows flow of water in
and out of the system.
Sight Glass (tube).
Allows direct observation
Submersible Turbine and Hydropneumatic
Tank (Typical for Home or Very Small System)
5-10
-------
Chapter 5 - Storage Facilities
Pump and Motor Controls. Control cut-in
and cut-out points.
High and Low Water Levels. Regulate
water level in tank.
Low Pressure or Flow Controls. Maintain
balance between water and air pressure.
Air Compressor. Forces additional air into
tank to increase pressure
(prepressurization).
Master Flow Meter. Measures quantity of
water pumped.
Cycle Counter. Counts number of pump
cycles.
Elapsed Time Meter. Records hours of
operation.
Different Styles of Pressure Tanks
Most hydropneumatic systems differ only in the
kind of pressure storage tank used. Primary
differences in tanks include:
Size.
Orientation (horizontal or vertical).
Methods of separating water and air.
Styles of Pressure Tanks
All these factors may contribute to the degree of
vulnerability to sanitary deficiencies. The three
kinds of tanks are described below:
Conventional Tank
Air cushion in direct contact with water;
air volume controls necessary.
Capacity ranges from a few to several
thousand gallons.
Vertical or horizontal placement.
Outlet located near bottom of tank.
Combined inlet-outlet or inlet-outlet
separated on opposite sides of tank to
provide chlorine contact time.
Air volume control located at the water/
air interface of tank; provisions available
for prepressurizing.
Floating Wafer Tank
Floating wafer (rigid floats or flexible
rubber or plastic) separates water and air,
but separation not complete; some loss of
air is expected, requiring occasional
recharging.
Vertical placement limits tank capacity.
Inlet and outlet combined at bottom of
tank.
Internal air check valve to prevent
premature loss of air due to electric
outage or excess water demand.
Tank with a Flexible Separator
Separator fastened around inside of tank
for complete separation of air and water,
either flexible diaphragm or bag type.
Vertical placement limits tank capacity.
Supercharged at factory or on site to
pressures just below pump starting
pressure.
Sanitary Deficiencies of
Hydropneumatic Storage Tanks
1. Is tank capacity adequate?
There are several formulas for determining
required tank capacity. Two methods, A and B,
are presented below. In selecting and
evaluating the tank, capacity must be matched
to the system's peak demand. Engineering
records, which should be available at the
facility, list pump capacity, cut-in, and cut-out
pressures. Operating records show current
peak demand and whether peak demand has
5-11
-------
How to Conduct a Sanitary Survey
changed since the tank was installed, which
could require a change in tank size.
[Note: To ensure against over stressing
facilities at peak demand, system operators
must know the pumping capacity and peak
demand rates.]
The inspector should be especially concerned
about the adequacy of supply capacity and
tank size in communities that have
substantially increased their service population
without upgrading the water system.
A. Tank Capacity Formula
Tank capacity = at least 10 times the capacity
of the well's largest pump, and
The well pumps = at least 10 times the average
daily consumption rate.
B. Alternative "Rule of Thumb"
The capacity of the wells and pumps must be
at least equal to the peak instantaneous
demand.
The active storage volume of the
hydropneumatic tanks must be sufficient to
limit pump cycling to manufacturer's and
industry recommendations.
Maximum cycling frequency must be
determined for the largest pump when demand
is one-half the capacity of the largest pump or
combination of pumps operated by the same
pressure switch.
2. Does low pressure "pump-on" level
maintain adequate distribution system
pressure?
Maintaining adequate pressure is especially
important to keep the water flowing from
storage facilities to serviced areas. Because the
pump and source have to be capable of meeting
the system's maximum momentary water
3.
situations and backflow or backsiphonage is
substantially increased. To prevent backflow
and backsiphonage, minimum pressure must be
maintained at all times.
Too little pressure can cause the water flow to
reverse, allowing water from a polluted source
to enter potable, stored water. Low pressure
can indicate improper connections, or cross
connections, made from storage to serviced
facilities. Too much pressure, on the other
hand, can strain system components, cause
high leakage rates, and force air out with
water.
System pressures (Pounds per square inch)
Optimum Working Pressure: 60-80 psi.
Minimum Working Pressure: 35 psi.
" Maximum Pressure at Service
Connections: 100 psi.
Minimum Pressure Under Fire Flow
Conditions: 20 psi.
Check for hazards. Inspectors should check
engineering records to assess potential
backflow hazards in the water of facilities
served by the system. They also should consult
operating records to see whether pressure is
adequate and they should determine whether
and how often breakdowns and pressure losses
occur.
Are instruments and controls adequate
and operational? Are they used and
maintained?
Proper operation and maintenance of the
storage system is also essential. Failure to
adjust gauges and controls properly can lead to
inadequate pressure or inadequate supplies of
water. And tanks equipped with air
compressors may be polluted by airborne or
waterborne foreign matter. Careful installation
and maintenance of air filters and cross-
connection control devices can prevent the
entry of foreign material into the
hydropneumatic system.
Components to be Checked. To ensure proper
operation and maintenance of the system, the
following components must be routinely
checked and adjusted for changes in the peak
demand:
Air volume control
5-12
-------
Chapter 5 - Storage Facilities
Relief valves
Motor controls
" High and low water level controls
Low pressure flow controls
Air compressor and controls
Check Records. Frequently, controls are not
adjusted after the system arrives from the
factory. Operating records should report the
original calibration and whether peak demand
has changed.
4. What are the cycle rate and air-to-water
ratio?
Cycle rate. The water supply pump should not
cycle frequently (10 to 15 cycles per hour is
acceptable). Frequent or constant operation of
the pump indicates a "waterlogged" tank,
improper settings on the pressure controls, or
system demand that is close to exceeding the
supply pump capacity.
Air-to-water ratio. The air-to-water ratio in
conventional hydropneumatic tanks should be
approximately one-third air to two-thirds water
at "pump off pressure. If the air volume is too
high, the tank could lose water before the pump
starts, which would send air into the
distribution system.
5. Are the tank and controls properly
protected?
The tank should be located in a secure building
or surrounded by a fence to protect it from
vandalism. The controls should be housed in a
waterproof and secure structure, but must be
easily accessible for maintenance. Lightning
protection should be included.
6. Are emergency procedures established?
Pump failurein either a low- or high-
pressure situationshould be detected by the
control system which activates an alarm. Some
alarm systems consist of a light or horn at the
facility. This type of alarm is not as reliable as
an automatic telephone dialer alarm, which can
be programmed to call several numbers until a
response is obtained.
7. Are there back-up systems?
Many water systems, especially small ones, do
not have redundant equipment. Inadequately
maintained hydropneumatic systems are
extremely prone to malfunction, and pressure is
usually lost before the problem can be
corrected. The sanitary deficiencies of pressure
loss due to equipment failure are substantially
reduced if back-up systems are provided.
Provisions for an emergency source of safe
water should be established.
Service contract. The utility should have a
service contract with an industrial controls
technician for maintenance and trouble-
shooting.
CAUTION: Hydropneumatic tanks are
pressure vessels. A pressure of 50 psi is
equivalent to 3.5 tons per square foot of tank
surface area. DO NOT TAP ON THE
TANKS!
8. Are the interior and exterior surfaces in
good condition?
The interior and exterior should be in good
physical condition. The inspector should check
for signs of coating failure and corrosion. The
inspector most likely will not be able to
examine the interior surfaces, but should
emphasize to the operator the importance of
regular inspections.
By reviewing maintenance records, the
inspector may determine if inspections are
being performed. Some states require all
pressure vessels to undergo regular hydrostatic
testing. The tank should not be buried.
9. Are tank supports adequate and
structurally sound?
The tank should be properly and permanently
supported. An inadequately supported tank
may shift and damage the piping connections.
10. Is the recharge air free of pollutants such
as oil from an air compressor?
Air compressors can introduce lubrication oil
as an aerosol into the hydropneumatic pressure
tank.
5-13
-------
Water Treatment
The sanitary survey inspector must thoroughly
evaluate all water treatment processes to ensure the
production of a safe, adequate, and reliable supply
of water for consumers. The water treatment plant
is the primary barrier against unsafe water, and any
malfunction in the treatment process could result in
water quality problems. The inspector must
evaluate the operation, maintenance, and
management of the water treatment plant to identify
any existing or potential sanitary deficiencies.
Learning Objectives
By the end of this chapter, learners should be able:
To identify key data items required to
evaluate sanitary survey risks at water
treatment plants such as turbidity, pH,
alkalinity, Stage 1 DBF Rule monitoring
plans, disinfection profiles, and chlorine
residuals.
To review key components of water
treatment processes such as chemical feed
systems, coagulation, flocculation, and
sedimentation processes, filtration systems,
and disinfection.
To recognize sanitary deficiencies of the
water treatment processes as they relate to
the physical facilities, operation and
maintenance, and management. Issues may
include inadequate treatment, inadequate
application of water treatment concepts to
process control, hydraulic surges, poor
maintenance procedures, staffing and
funding deficiencies, and cross-connections.
To identify safety issues that affect the
operations staff, and could affect the
facility's ability to perform effectively.
Safety issues may include chemical
handling, chemical storage, and confined
spaces.
To review regulatory issues that are
appropriate to each specific process to
determine their relationship to sanitary
deficiencies.
Data Collection
The inspector needs to obtain as much of the
following information about the water system as
possible before the sanitary survey inspection.
Information and data not obtained during the
investigation must be obtained during the
inspection.
Treatment Processes Information
Schematic of complete treatment facilities
showing the type of treatment processes
used and application points of all chemicals.
Chemicals Used in Treatment Process
Information and Data
Specific chemicals used and purpose of
addition.
Quantity added.
Application points.
Chemical Feed Equipment and Storage
Information and Data
Type of feed system in operation (i.e., liquid,
gas, solid).
Condition of equipment.
6-1
-------
How to Conduct a Sanitary Survey
Calibration procedures.
Redundancy for all systems.
Safe and adequate chemical storage.
Process Control Data
Type and frequency of testing throughout
treatment process.
On-line monitoring equipment available and
operable.
Data recording procedures.
Physical Facilities Information
Buildings and rooms where treatment
processes are located; adequacy of
accessibility, safety, and overall
maintenance.
Operation, maintenance and design of
treatment units such as rapid mixers,
flocculators, clarifiers, and filters.
Regulations and Standards to
Consider
The inspector needs to consider and review the
following information prior to the inspection:
Chapter 2 of this Guide.
Specific regulations that apply to the
facility.
Past inspection reports to identify previous
compliance problems.
Water Treatment Processes
Basic Information
Purpose of Water Treatment. The purpose of
water treatment is to condition, modify, or remove
undesirable impurities or pathogens in order to
provide water that is safe, palatable, and
acceptable to consumers. National standards for
some of the impurities that are considered
important to the health of consumers are set under
the federal Safe Drinking Water Act (specified in
40 CFR Part 141 with maximum contaminant
levels [MCLs] and treatment techniques). If the
levels of contaminants present exceed the
established MCLs, the water must be treated to
reduce the levels. Techniques are specified in the
regulations when MCLs are not appropriate for
public health protection.
Secondary standards for some impurities that affect
the aesthetic qualities of water are found in 40
CFR Part 143. These standards are not enforceable
by the federal government, but states may choose
to adopt and enforce them. Treatment or
modification of the water to comply with secondary
standards is highly recommended because
consumers may seek out unsafe sources if the
drinking water supplied by the public system has
an undesirable appearance, taste, or odor.
Treatment Processes
Some of the common treatment processes for
surface and ground water are discussed below.
Pretreatment. Pretreatment is a physical,
chemical, or mechanical process that removes some
impurities or alters some of the objectionable
characteristics of water (such as taste and odor,
iron and manganese, organics, or hardness) before
it is treated further. On occasion, chemical addition
to alter the water quality is the only treatment
technique used. This technique may include
corrosion control, iron and manganese
sequestering, disinfection, and fluoridation.
Coagulation and Flocculation. Coagulation and
flocculation are chemical and physical processes to
improve the paniculate and colloid-reduction
efficiency of subsequent settling or filtration
processes. Coagulation involves feeding chemicals
to destabilize the similar charges on suspended
particles, allowing them to coalesce and thereby
begin to form floe. Flocculation, which partly
overlaps the coagulation, requires gentle mixing of
destabilized particles to form floe that can be
removed by settling or filtering.
Sedimentation. Sedimentation follows coagulation
and flocculation. In sedimentation, the velocity of
the water is reduced to allow the flocculated
particles to settle out and be removed before
filtration.
6-2
-------
Chapter 6 - Water Treatment Processes
Filtration. Filtration is the passage of water
through a porous filtering medium, such as sand,
anthracite, or other granular material, to remove
most of the remaining destabilized particulate
impurities and floe.
Disinfection. Disinfection is the process of
destroying pathogenic organisms using chlorine,
certain chlorine compounds, or other means.
Chemical Feed Systems
Chemical feed systems are common to all types of
treatment plants. They may be used to feed
treatment chemicals such as coagulants, and
oxidants into the water. They may also be used to
feed corrosion inhibitors, pH adjustment chemicals,
chemicals for taste and odor control, disinfectants,
and fluoride. Types of chemical feed systems
include liquid feed pumps and dry feeders.
Liquid feed pumps. These systems are very
simple, as illustrated in the drawing below. The
system is made up of these basic components:
Tank to hold the chemical solution.
Chemical feed pump.
Liquid Feed Pump
(Hypochorinator)
Injection valve with check valve.
Electrical control system with fail safe flow
switch.
Chemical storage area.
Dry Feeders (Volumetric). In these feeders,
the feed rate is based on the volume of
chemical rather than weight. Volumetric
feeders can achieve acceptable performance
for materials with stable density and
uniformity, particularly at low feed rates.
Dry Feeders (Gravimetric). This type of
system feeds dry chemicals based on actual
weight. Consequently, it is more accurate
than other types of dry feeders and better
able to achieve the desired dose rates.
Operation and Maintenance of
Chemical Feed
The proper operation and maintenance of chemical
feed systems is critical to the overall performance
of the treatment plant. For example, a conventional
surface water plant cannot consistently achieve
optimum performance unless its chemical feed
systems are functioning properly. Issues to be
addressed by inspectors for all chemical feed
systems include:
Adequate maintenance, including a
preventive maintenance (PM) program,
spare parts for critical component and
components that need regular replacement,
and repair budgeting.
Back-up units for redundancy, particularly
for critical processes such as coagulation
and disinfection.
Physical condition of buildings and areas
where feed equipment is being housed.
Storage of chemicals, including the
segregation of incompatible chemicals that
should not be stored together. For example,
storing powdered activated carbon (PAC)
and potassium permanganate (KMnO4) in
the same area could result in explosion or
fire hazards. Chemicals should not be stored
6-3
-------
How to Conduct a Sanitary Survey
Volumetric Dry Feeder
MOTOR
ROTATING &
RECIPROCATING
FEED SCREW
ATMOSPHERIC
VACUUM
BREAKER
Belt Gravimetric Dry Feeder
?
6-4
-------
Chapter 6 - Water Treatment Processes
Chemical Feed System
CHEMICAL
STORAGE
TANK
2. What is the amount of
chemicals used?
The amount of chemicals used
should be based on testing. The
operator should be able to
explain how the dosage is
determined (such as by jar
testing, pH measurement, or
streaming current detectors) and
the frequency with which this
determination is made. The
chemicals should be approved
for use in potable waters by
ANSI/NSF or other acceptable
federal or state standards.
3. Where is each chemical
applied?
where they could contaminate the system's
water supply in the event of a spill.
A hazardous communication program in
place, to deal with the handling of all
chemicals.
Containment of chemical spills and the
location of proper drains in chemical areas.
Safety in terms of the handling and feeding
of chemicals and the availability and proper
use of safety equipment such as chemical
goggles and respiratory protection.
Calibration of all chemical feed systems as a
regular operational procedure.
Sanitary Deficiencies - Chemical
Feed Systems
1. What chemicals are used?
The inspector should determine what chemicals
are used, if they are approved for water
treatment, and if they are applied properly. The
operator should be aware of possible adverse
effects of adding the chemicals, such as the
development of trihalomethanes (THMs) as a
result of pre-chlorination.
The inspector should note the
application points and evaluate them in light of
the purpose of the chemical addition.
Chemicals may counteract each other if not
applied in the proper sequence. For example,
PAC will remove chlorine if it is fed
downstream of the chlorine injection point.
This situation often unintentionally wastes
chlorine and PAC. Similarly, sequestering
agents fed to control iron or manganese must
be added ahead of chlorine because the chlorine
will oxidize the dissolved metals and render the
sequestering chemicals useless. Insoluble
calcium fluoride may precipitate out of the
water if fluoride compounds and lime are
added in close proximity to each other, another
possible result of inappropriate application
points. Chemical addition should not result in a
cross-connection. Certain chemicals, such as
corrosion inhibitors or fluoride, will generally
be applied at the end of the treatment process.
As a general rule, the inspector should know
the application points and feed rates of all the
chemicals used in the system's treatment
plants. The inspector must understand the
purpose of the chemicals in order to evaluate
the feed locations and rates. Therefore, the
inspector will often need to perform, either
before or after the survey, some research on the
chemicals used by the system.
6-5
-------
How to Conduct a Sanitary Survey
4. Does the system have adequate monitoring
and testing procedures?
Systems should monitor for the chemicals
added as well as for the chemicals to be
removed. This monitoring requires following
standard testing procedures and using properly
calibrated and maintained monitoring and
testing equipment. The system should have
adequate facilities to undertake monitoring and
testing.
5. What is the condition of the chemical feed
equipment?
The equipment must be functional and properly
maintained. For example, with dry chemical
feeders the inspector should watch for
problems with "bridging" of the chemical in the
hopper. Liquid feeder lines should be checked
to see that they are not clogged. There should
be chemical feeder redundancy.
Chemical feed pump diaphragm foot valves,
injection valves, and control valves should be
replaced at least once a year. The suction and
discharge piping should be inspected for
discoloration and clogging. When clear plastic
lines turn opaque, they should be replaced. The
inspector should determine if there is a
preventative maintenance program in place and
should examine PM and repair records. The
chemical addition program is vital to ensure
proper treatment and cannot be interrupted due
to equipment malfunction. Therefore, the
operator should have adequate spare parts or
redundant equipment.
6. Is the chemical feed equipment calibrated?
The equipment should be calibrated each time
a new batch of chemicals is used. The feed
equipment feed rate should be checked at least
daily.
Ideally, the operator should calibrate chemical
feed pumps at least annually. An alternative
method is to use a graduated cylinder to verify
the feed rate weekly or monthly.
7. Are instrumentation and controls for the
process adequate, operational, and used?
Controlling processes is difficult when
instrumentation such as flow meters,
turbidimeters, and chlorine residual analyzers
are not functional or properly calibrated. The
inspector should observe the controls and ask
the operator about calibration checks and how
process control decisions are made based on
the results of the measurements. The
instrumentation is useless if the operator does
not know the significance of the measurement.
8. Is chemical storage adequate and safe?
A minimum of a 30-day supply of chemicals is
recommended. Level indicators, overflow
protection, and spill containment should be
provided for liquid chemical storage. This is
particularly important to prevent contamination
of the aquifer by tanks located near a well.
Chemicals stored in the same area should be
compatible. For example, petroleum-based oils
and lubricants must not be stored near
oxidizers such as KMnO4 because of fire and
explosion hazards. Chemicals must be stored in
a manner that precludes a spill from entering
the water being treated or the raw water
source.
PAC storage areas need to be dry and equipped
with an explosion-proof electrical system.
Make sure that sodium fluoride is stored in a
separate area and not with any other chemicals.
Sodium fluoride is very corrosive and a poison.
Check on access to the chemical storage. If
access is difficult, the operator may not be
diligent in transferring chemicals from storage
to use.
9. Do daily operating records reflect
chemical dosages and total quantities
used?
It is extremely critical that the operator monitor
daily chemical use and dose rates. Overfeeding
chemicals can be as detrimental as under-
dosing. Monitoring feed rates is key to the
optimized performance of any chemical feed
system.
6-6
-------
Chapter 6 - Water Treatment Processes
10. Is the chemical feed system tied to flow
(i.e., flow paced)?
The chemical feed pump can be paced with the
flow by a 4 to 20 mA signal from a flow
recorder, or the system may be tied directly to
a pump so the feeder is activated each time the
pump is operated and there is flow in the line.
When the chemical feeder is tied to a pump, it
is very important that some type of flow sensor
be used as a fail safe. The chemical feeder
should not be allowed to come on until there is
flow in the pipe. Without flow control, a pump
motor starter may engage but not start the
pump. If the signal that engages the starter also
starts the chemical feed system, highly
concentrated chemicals can be fed into the line
and received by a customer.
11. Is there an operating 4-in-1 valve or
equivalent on each feed pump?
This valve reduces the possibility of siphoning
all of the chemical into the system and protects
the pump from damage due to shutdown of the
discharge piping. Ask the operator to show you
how it works.
12. Is there a hazardous chemicals protection
and communication program in place?
The utility needs to have an inventory of all
hazardous chemicals, a Material Safety Data
Sheet (MSDS) for each chemical, and written
procedures for using, transporting, and
handling these chemicals. The utility also
should have an emergency response plan in the
event of a spill of hazardous chemicals.
13. Is there appropriate safety equipment
(e.g., cartridge respirator for calcium
hypochlorite) and personal protective
equipment (PPE) (e.g., goggles and
gloves) available and in use? Have
operators been trained to use the safety
equipment?
The PPE should be in good condition;
respirators must be clean and stored in a sealed
bag. PPE should be readily available in the
location where it will be used. Facility
management is responsible for training all
personnel in the use of safety equipment. Ask
for documentation that this training has
occurred during the past 12 months.
When respiratory protection is required, the
utility must have a written respiratory
protection program. This program includes a
fit test of the device and training in selection,
use, and care of the device. In addition, the
program requires annual physical exams of all
personnel required to use the devices.
Cartridges on cartridge respirators must be
changed at least every 6 months. All
respirators must be inspected monthly.
14. Is the building as clean and dry as
possible?
Keeping the interior of the building clean and
dry reduces the opportunity for spills of liquid
or powdered chemicals to react with water,
increasing corrosion in the building. When
calcium hypochlorite mixes with water,
chlorine gas escapes into the atmosphere. This
gas will increase the rate of corrosion and
deterioration in the facility.
Treatment Processes
Disinfection
Introduction. Disinfection is the process of
destroying a large portion of the microorganisms in
water, with the probability that all pathogenic
bacteria and viruses are inactivated in the process.
Many failures to meet drinking water standards are
directly related to inadequate disinfection. In
addition, chlorine, the most widely used
disinfectant, is a hazardous chemical and can cause
severe health problems or death for the operator
and the public. The inspector must determine if the
disinfection system is adequate and reliable. This
will help ensure that the water is safe to drink.
Disinfection Methods. Chlorination is the most
common disinfection method used by water
systems in the United States. While chlorine is the
most common, there is a general trend in the
industry to experiment with other disinfection
systems such as:
Ozone
Ultraviolet (UV) light
6-7
-------
How to Conduct a Sanitary Survey
Chlorine dioxide
Chloramination
While these methods are used in some systems,
both ozone and UV require the addition of chlorine
to meet the residual requirements of the Surface
Water Treatment Rule (SWTR), 40 CFR 141.73.
Because chlorine is the primary method of
disinfection, only this equipment will be discussed
in this lesson.
Dosages and Residuals
Review of Terms. The standard term for the
concentration of chlorine in water is milligrams per
liter (mg/L). The concentration of chlorine gas in
the atmosphere is measured in parts per million
(ppm).
Dosage. The total amount of chlorine fed into a
volume of water by the chlorinator is the dosage.
This value should be calculated daily in mg/L.
Operators are more likely to record the dosage as
pounds or gallons per day. While the number of
pounds or gallons used per day is important, it is
not the dosage but the feed rate.
Demand. Chlorine is a very active chemical
oxidizing agent. When injected into water, it
combines readily with certain inorganic substances
that are oxidizable (e.g., hydrogen sulfide, nitrate,
and ferrous iron), organic impurities including
microorganisms, and organic nitrogen compounds
such as protein and amino acids. These reactions
consume or use some of the chlorine. The amount
used is called the chlorine demand. Because the
reaction time between chlorine and most organic
compounds is long (hours to days), the demand is
based on time. That is, the measurable demand at
the end of 20 minutes is less than the measurable
demand at the end of one hour of contact.
Residual. Residual is the amount of chlorine
present in the water after a specified period of time.
It is measured in mg/L.
Chlorine demand (mg/L) = Chlorine Dose (mg/
L) - Chlorine Residual (mg/L)
Chlorine and Water. Regardless of the form of
chlorination-chlorine gas or hypochlorites-the
reaction in water is basically the same. Chlorine
mixed with water will produce two general
compounds, HOC1 (hypochlorous acid) and OC1
(hypochlorite ion). The measurement of these
compounds is called free chlorine residual. If
organic or inorganic compounds, especially
nitrogen compounds, are available, the HOC1 will
combine with them to produce chloramines or
chloro-organic compounds. The measurement of
the presence of these compounds in water is called
combined chlorine residuals.
Germicidal Effectiveness. It is commonly agreed
that a free chlorine residual of HOC1 and OC1 is
much more effective as a disinfectant than a
combined chlorine residual.
Breakpoint Chlorination. To produce a free
chlorine residual, enough chlorine must be added to
destroy the nitrogen compounds. This process is
called breakpoint chlorination. While this process
destroys most of the nitrogen compounds, it does
not destroy all of them. Those that remain combine
with the chlorine to produce what is called the
irreducible combined residual.
Free + Combined = Total. For many systems, this
results in a residual in the distribution system that
includes free and combined residuals. The
measurement of both of these residuals is called
total chlorine residual. The combined residuals
are the primary contributors to taste and odor
problems in a system. The table below shows the
threshold of odor of various residuals. It is
apparent that free chlorine and monochloramine are
likely to produce fewer taste and odor complaints.
Compound
Free HOCI
Monochloramine
Dichloroamine
Nitrogen trichloride
Threshold of Odor
20 mg/L
5 mg/L
0.8 mg/L
0.02 mg/L
Taste and Odor Considerations. As can be seen
from the table above, taste and odor complaints
result primarily from combined residuals that form
after enough chlorine has formed to produce
dichloramines and nitrogen trichloride. If the
system operates with a free chlorine residual but
receives chlorine taste and odor complaints, the
inspector should suggest that the operator measure
both free and total residuals. As a rule of thumb, if
6-8
-------
Chapter 6 - Water Treatment Processes
Reactions of Chlorine in Water
0.5
0.4
,0.3
g
to
£0.2
0.1
Demand
Combined Residual Chlorination
Formation of chloro-organic
compounds and chioramines
Destruction ot
chioramines and
chloro-organic
compounds
Formation of free residual
0.1
0..2
0.3
0.4 0.5 .06
CHLORINE ADDED mg/L
0.9
1.0
the free chlorine residual is less than 85 percent of
the total, the odor and taste problem is a result of
combined residuals. This problem may be resolved
in two ways:
Remove the precursors that cause the
combined residuals.
Increase the chlorine dosage. There may be
an insufficient quantity of chlorine (pound
for pound with the organics) to oxidize the
organic compounds sufficiently to avoid the
problem.
When a system uses chioramines as a residual
disinfectant, the operator must pay close attention
to the chlorine-ammonia feed ratio to ensure that
the residual is monochloramine.
Stage 1 Disinfectants and Disinfection
Byproducts (DBF) Rule. Two considerations for
the sanitary survey inspector from the Stage 1 DBF
Rule should be the development of disinfection
byproducts (i.e., total trihalomethanes [TTHMs]
and haloacetic acids [HAA5]) and maximum
residual disinfectant levels (MRDLs). Production
of disinfection byproducts such as TTHMs and
HAA5 can, in most cases, be dramatically reduced
by discontinuing prechlorination at a surface water
treatment plant. However, prechlorination may
have a significant impact on the coagulation
process and the disin-fection benchmark.
Therefore, the
inspector
should not
suggest that
prechlorination
be discon-
tinued without
fully under-
standing the
system's
specific
situation.
Review the
Stage 1 DBF
Rule for
information
on maximum
allowable
residual
disinfectants,
MCLs for
disinfection
byproducts, and treatment technique requirements
(i.e., enhanced coagulation and enhanced
softening).
Sanitary Deficiencies -
Disinfection Dosages and
Residuals
1. Can the operator answer basic questions
about the disinfection process, including
what is done, and when and why it is
done?
An operator's lack of knowledge of the process
and equipment indicates that equipment failure
or process effectiveness may not be resolved in
a timely manner. Management is responsible
for ensuring that operators are well trained
in the use and maintenance of disinfection
equipment. Lack of knowledge of this key
process can be considered a significant sanitary
deficiency.
2. Have there been any interruptions in
disinfection? If so, why?
If disinfection is provided because the system
uses a surface water source or has had a
bacteriological problem, then interruption of
service is a significant consideration.
Interruptions often occur when a chemical feed
6-9
-------
How to Conduct a Sanitary Survey
pump fails or during cylinder changes when
only one cylinder at a time is connected to the
system.
3. Is a proper residual entering the
distribution system at all times?
The SWTR requires that a residual of 0.2 mg/
L be present at the entry point to the
distribution system. This residual must occur
after sufficient contact time to meet the
SWTR's inactivation requirements. Some
states may require a higher residual at the entry
point to the system. In addition, the inspector
should verify where this point is in the system
and that the residual is measured at this point
at least daily.
If the system adds ammonia to create
choramines, the residual will be a combined
chlorine residual and should generally be
considerably higher than 0.2 mg/L. Although
this is state-specific, the most common
requirement is 2.0 mg/L.
4. What disinfectant residual is maintained?
The SWTR requires that a trace of chlorine
residual be maintained at all coliform sampling
points in the system, but some states may
require a higher value. The inspector should
verify that chlorine testing sites are
representative of the system and thus provide
sufficient information to ensure that a trace is
available at all points and that MRDLs of the
Stage 1 DBPR are not exceeded. The inspector
may wish to measure residuals at points of
high residence time.
In addition to verifying that there is a proper
residual, the inspector should determine
whether the equipment and testing methods are
adequate. See the Distribution and Monitoring
chapters (7 and 9, respectively) for more
details on testing.
5. Is the contact time between the point of
disinfection and the first customer
adequate?
The contact time is the interval in minutes (T)
that elapses between the time when chlorine is
added to the water and the time when that same
slug of water passes by the sampling point. A
certain minimum period of time, depending on
disinfectant residual concentration (C), water
temperature, and other factors, is required for
completion of the disinfection process. The
requirements for contact time (T) and
disinfectant residual concentration (C) depend
on the pH, temperature, and flow rate of the
water.
In general, the contact period for ground water
systems should be adequate to ensure
inactivation of 4 log viruses under peak
demand flow conditions. The contact period for
surface water systems must be adequate to
ensure compliance with the requirements of the
SWTR. More time may be desirable under
unfavorable conditions, such as when the raw
water has high levels of microbial
contamination.
To determine if disinfection is adequate to
remove and inactivate viruses and Giardia
cysts, the SWTR requires unfiltered systems to
determine CT values and show they are
adequate to ensure inactivation of 4 log viruses
and 3 log Giardia lamblia. CT is measured in
milligram-minutes per Liter (mg-min/L) and is
calculated as shown in the following equation.
Disinfectant residual concentration in mg/L
(C) X contact time in minutes (T) = CT in
mg-min/L
Filtered systems must show that filtration and
disinfection combined provide the required 3
and 4 log inactivation or removal of Giardia
and viruses. More complete information on the
requirements and methods for determining CT
values is provided in the SWTR and SWTR
Guidance Manual.
6. Are the temperature and pH of the water at
the point of chlorine application measured
and recorded daily?
The CT value required for proper inactivation
of Giardia and viruses depends on the pH and
temperature of the water. Therefore, the SWTR
requires operators to take these two
measurements daily and calculate CT at peak
hourly flow. The pH must be measured with a
meter, not with litmus paper or a color
comparitor, and the temperature must be
measured with a calibrated thermometer.
6-10
-------
Chapter 6 - Water Treatment Processes
Hypochlorination Systems
Facilities
Introduction. Modern hypochlorination systems
are very reliable and effective. With the
implementation of new regulations regarding
chlorine, many small and medium-size facilities
have switched to this safe, easy method of
disinfecting water. The primary disadvantage of
hypochlorniation systems is their higher annual
operating costs compared to gas systems. However,
as a result of new safety and environmental
regulations, the cost of using chlorine gas has
continued to rise, making hypochlorination systems
more desirable. Water systems must list
hypochlorites in their hazardous materials
inventories, and they must have written procedures
for handling hypochlorites, using them, and
responding to spills. This is an OSHA requirement.
Sodium Hypochlorite Considerations. Of all the
chlorine disinfection products, sodium hypochlorite
presents the least handling hazard to the operator.
Sodium hypochlorite is available in concentrations
from 5 percent to 15 percent. It carries a UN
number of 1791 and is classified by DOT as a
corrosive with a hazard classification of 8.
Personal protective equipment for handling sodium
hypochlorite includes chemical goggles and gloves.
Calcium Hypochlorite Considerations. Calcium
hypochlorite is a powder containing chlorine in
concentrations up to 67 percent. It is usually mixed
with water to form a 1 percent to 3 percent
solution, which is fed into the water system.
Calcium hypochlorite can be difficult to dissolve in
hard water (above 125 mg/L total hardness). It has
a UN number of 1748 and is classified by DOT as
an oxidizer with a hazard classification of 5.1. The
dust from calcium hypochlorite powder or tablets
contains chlorine in concentrations up to 67
percent. Therefore, the required personal protective
equipment for handling includes a cartridge
respirator for chlorine with a dust filter, chemical
goggles, and gloves.
Sanitary Deficiency -
Hypochlorination Systems
Facilities
[Note: The sanitary deficiencies related to
Chemical Feed Systems and Disinfection -
Dosages and Residuals earlier in this chapter
should also be applied to this section.]
1. What kind of hypochlorite is used (e.g.,
calcium, sodium, or others)?
Sodium hypochlorite is vulnerable to a
significant loss of available chlorine over time.
The deterioration of sodium hypochlorite
solutions is more rapid with increasing
concentrations and increasing temperatures.
Thus, the inspector should ask how much
chemical is on hand and how old it is. The
table below shows the half life deterioration of
sodium hypochlorite. This information can be
used by systems to determine the concentration
of solution that best fits their needs.
Sodium Hypochlorite
Half Life (Days)
Percent
10.0
5.0
2.5
0.5
Temperature
21 2° F
0.079
0.25
0.63
2.5
140°F
3.5
13.0
28.0
100.0
77° F
220
790
1,800
6,000
59° F
800
5,000
Sodium hypochlorite is a corrosive liquid. It
should not be stored with dry chemicals or
other liquids with which it can react, such as
petroleum products.
Calcium hypochlorite has a long life, but feed
equipment requires greater maintenance than
when sodium hypochlorite is used. The calcium
hypochlorite solution contains a great deal of
abrasive material that deteriorates the chemical
feed pump suction and discharge valves.
Calcium hypochlorite is a fairly reactive
oxidizer that should not be stored with other
chemicals with which it can react. Under no
conditions should petroleum products be
6-11
-------
How to Conduct a Sanitary Survey
stored with calcium hypochlorite. The
reaction between chlorine and petroleum
products is quick and violent.
2. Is the solution tank covered to minimize
corrosive vapors?
If the tank is not covered, chlorine gas will
escape into the room and deteriorate the
equipment.
3. Is there adequate spill containment?
A double tank or containment area must be
installed around all chemical storage tanks. A
spill of 10 gallons of hypochlorite or 100
pounds of dry calcium hypochlorite is a
reportable incident under the Comprehensive
Environmental Response, Compensation and
Liability Act (CERCLA).
4. Are safe practices followed during
chemical handling and mixing?
Observe operator PPE and the space where
chemicals are stored and used. If PPE does not
appear to have been used, or the space is not
clean, the inspector can assume that safe
practices are not being followed.
Gas Chlorination Systems
Gas Systems
A wide variety of gas systems is produced by
various manufacturers. The inspector need not be
familiar with all of these systems. All chlorinators
manufactured in the United States are vacuum
operated. This is a basic safety feature. The
systems used by small water utilities fall into one
of three general categories:
Pressure systems
Remote vacuum systems
Cylinder-mounted systems
The easiest way to tell a remote vacuum system
from a pressure system is to look at the line from
the cylinder to the chlorinator. If the line is metal,
the system uses gas under pressure between the
cylinder and the chlorinator. If the line is plastic,
the water system uses a remote vacuum system;
gas is under a vacuum between the cylinder and
the chlorinator.
Facility
The drawing on the next page shows the key points
of a small gas-chlorine facility that meets current
OSHA and Uniform Building Code requirements.
In general, these include:
Containment of the chlorine, should there be
a release or leak.
Air treatment system so that the exiting air
does not exceed 50 percent of the
Permissible Exposure Level (15 ppm is 50
percent).
Gas leak alarm system.
Crash bars on doors.
Negative pressure in the room when the air
treatment system is operating.
Overhead sprinkler system with a 20-minute
capacity.
Containment of the air treatment system and
sprinkler water.
Emergency power for the air treatment
system.
Booster pump to provide pressure to the
injector.
Scales to weigh the cylinders.
Gas Containers
Gas chlorine is provided in 100-pound and 150-
pound cylinders, 1-ton containers, and tank cars.
(These values are the net weight of liquid chlorine
in the container.) Most small systems use 100- and
150-pound cylinders.
Hazard Assessment
Gas chlorine is classified as a poison gas and an
inhalation hazard by OSHA, EPA, and DOT. The
UN number for chlorine gas is 1017, and the DOT
classification hazard number is 2.3 (poison gas).
6-12
-------
Chapter 6 - Water Treatment Processes
Chlorine Gas Treatment Room
[Note: Gas chlorine has been reclassified. As a
result, different regulations apply to gas
chlorine.]
Safety Consideration
The inspector must focus on the adequacy and
reliability of the chlorination system to provide
disinfection. However, the threat of injury or illness
to the operator caused by the chlorination system
means a review of the major safety considerations
for gas chlorination systems is advisable.
Sanitary Deficiencies - Gas
Chlorination Systems
Facility
[Note: The sanitary deficiencies related to
Chemical Feed Systems and Disinfection -
Dosages and Residuals earlier in this chapter
should also be applied to this section.]
1. How are leaks detected? At what detection
concentration are automatic detectors set
and have they been tested recently?
Automatic detectors should be tested at least
monthly. This test can be done by placing a
small pan of bleach under the air intake and
adding some vinegar.
Many operators set the detection level at the
high end of the range, although it should be set
at the low end (I ppm). Although this situation
may not constitute a sanitary deficiency, it does
not comply with current OSHA
recommendations.
2. Is the sensor tube for the automatic
detector near the floor level? Is the tube
screened?
Look at the leak detector. Because chlorine gas
is heavier than air, the intake should not be
more than 12 inches from the floor. Some new
detectors use solid state sensors, which must be
replaced each year.
6-13
-------
How to Conduct a Sanitary Survey
3. Is the chlorination equipment properly
contained?
To meet current Uniform Fire Code 6.
requirements, the room that houses the
chlorination equipment must be designed to
fully contain a chlorine release or leak.
One common deficiency of these rooms are
floor drains. They often are connected to other
parts of the facility and should be sealed when
not being used for floor cleaning.
4. Is the chlorination room vented at floor
level with an adequate make-up air supply
coming from the ceiling across the room?
Is the vent switch located outside by the
door? Does the system store chlorine gas
in quantities sufficient to be covered by
the Uniform Fire Code?
The air exhaust and intake systems must be
designed to provide a slight negative pressure 7.
in the chlorine room when the air ventilation
system is operating. A switch on the outside of
the door allows the operator to turn on the air
handling system prior to entry. The ventilation
system may be wired to come on automatically
when the door is opened or when the light is
turned on.
Systems which have chlorine gas in quantities 8.
that are covered by the Uniform Fire Code
must be equipped with scrubbing devices that
will keep chlorine concentrations below 10
ppm1 in discharges of contaminated air.
Many organizations have classified chlorine
rooms as confined spaces. [Note: Do not enter
if you are not sure that the air handling
system is operating properly.]
5. Does the door in the chlorination room
open out and have a panic bar and a 9.
window?
The panic bar and outward-opening door are
OSHA requirements and not a direct sanitary
deficiency. The window allows the operator to
observe the conditions in the chlorine room
1 Handbook of Chlorination and Alternative
Disinfectants, Fourth Edition, G.C. White.
without entry, thus reducing exposure to
hazardous conditions.
Are there any cross-connections in the
chlorine feed make-up water or injection
points?
A common cross-connection problem in
chlorination facilities is a drinking water
connection to the injector and the make-up
water for hypochlorination systems. There
must be a physical separation or an acceptable
backflow preventer between the drinking water
system and the feed water to the injector.
An atmospheric vacuum breaker must be
installed on make-up water lines. A pressure
vacuum breaker must be used if there is a shut-
off valve on the discharge end of the make-up
water line, such as a nozzle on the end of the
hose.
Is there an alarm tied to interruptions in
the chlorine feed?
Low system vacuum and low cylinder pressure
are the two most common alarm systems. If
there is an alarm system, does it work? Does
the system shut down the flow of water, or just
initiate an alarm?
Does the system use automation, pace
with flow, chlorine residual analyzer, or
other system to adjust feed rates? Does it
work?
It is common to find automatic equipment that
does not work. Determine whether the system
provides adequate residual during high flows
and whether the residuals are higher during low
flows. Failure of the system to follow the flow
conditions is a significant sanitary deficiency.
Is there more than one cylinder, and are
they equipped with a manifold and an
automatic switch-over to avoid running
out of chlorine?
The inspector should determine whether the
switch-over devices work. If there is only one
cylinder, determine if the operator shuts off
water flow when the cylinder is changed. If
not, the disinfection is interrupted.
6-14
-------
Chapter 6 - Water Treatment Processes
10. Are the cylinders on a working scale?
A scale must be used to determine the amount
of chlorine used each day. To calculate dosage
and signal the amount of chlorine remaining in
the cylinders, scales must be maintained and
calibrated.
11. Are the tanks in use a quarter turn open
with a wrench in place for quick turnoff?
Full feed of 40 pounds per day can be obtained
from a cylinder by opening the valve one-
quarter of a turn. Opening the valve more is
not necessary. By opening it only one-quarter
of a turn and leaving the wrench in place, the
operator can quickly shut down the cylinder if
there is a release.
12. Are all cylinders properly marked and
restrained to prevent falling?
Cylinders should be marked and stored in a
manner that clearly indicates which cylinders
are full and which are empty.
All cylinders must be restrained two-thirds of
the way from the bottom with a chain that
prevents falling. In an earthquake zone, they
must also be restrained at or near the bottom.
13. Does the facility transport gas chlorine
cylinders? If so, are the requirements of 49
CFR parts 171 and 172 followed?
Remember, this is not a direct sanitary
deficiency. However, cylinders that are
transported must be secured in two locations,
and the vehicle must have DOT placards on all
sides. The driver must have a Commercial
Drivers License (CDL) with a hazardous
material rider. In addition, these regulations
require specific training and other
transportation considerations.
14. Is the proper concentration of ammonia
available to test for leaks?
Use a concentrated ammonia solution
containing 28 to 30 percent ammonia as NH,
(this is the same as 58 percent ammonium
hydroxide or, HN4OH, commercial 26°
Baume). Household ammonia is not strong
enough to reliably indicate a chlorine leak.
15. Are there adequate leak containment
provisions?
The Uniform Building Code requires the air
treatment system and fire sprinkler water to be
totally contained.
16. Are safe practices followed during cylinder
changes and maintenance?
The key here is training. Has the utility
provided detailed training on handling and
changing cylinders? This training should be
documented and practiced at least yearly.
Check to see if there is a written standard
operating procedure (SOP) for changing
cylinders. If not, there is no assurance that the
staff is using a safe procedure, and it is not the
inspector's job to have them change a cylinder
in order to determine if the procedure is safe.
17. How many individuals are present when
the chlorine cylinders are changed?
Industry standards call for two people, one to
change the cylinder and one to watch. If this is
not possible, switching to hypochlorination
may be a safer option.
18. What type of respiratory protection is
used?
When respiratory protection is required, the
utility must provide a written respiratory
protection program. This program includes a
fit test of the device and training in its
selection, use, and care. In addition, the
program requires annual physical exams of all
personnel required to use the devices.
Cartridges on cartridge respirators must be
changed every 6 months. All respirators must
be inspected each month.
The current thinking on self-contained
breathing apparatuses (SCBAs) is to limit their
use to emergency response crews and to have
operators use an emergency escape mask,
either cartridge or self-contained. (Many small
systems depend on the local fire department
because of the risks associated with chlorine
gas and on-going training requirements to
maintain proficiency.) To use a SCBA in a
6-15
-------
How to Conduct a Sanitary Survey
hazardous atmosphere requires a minimum of
three people, two with SCBAs and total
containment suits and one observer. In
addition, the personnel must be trained in
hazardous material response.
19. Is there an emergency plan, and when was
it last practiced?
The facility must have a written emergency
evacuation plan and should practice
implementing the plan at least annually. This is
an OS HA requirement.
20. What is the operating condition of the
chlorinator?
Gas chlorinators should be disassembled,
cleaned, and rebuilt each year. The rotameter
can provide a clue as to the frequency of
cleaning. If it is coated on the inside with a
heavy green or blackish film, the machine is
past due for cleaning.
In addition, general appearance can also be a
key. Check preventative maintenance and
repair records and determine whether
preventative maintenance is routinely
performed. Some indicators of problems for
gas chlorination are valves, piping, and fittings
that are damaged, badly corroded, or loose; no
gas flow to the chlorinator; and frost on tank,
valves or piping.
21. Is redundant equipment available, and are
there adequate spare parts?
Disinfection must be
continuous. Therefore,
stand-by equipment of
sufficient capacity to replace
the largest unit is
recommended. If stand-by
equipment is not available,
flow to the water system
should be stopped and
critical spare parts should be
on hand for immediate
replacement. At a minimum,
the system must have spare
diaphragms and a set of lead
gaskets.
22. Are the appropriate lighting, guards, and
railings in place? Are there other safety
concerns, such as electrical hazards?
All electrical fixtures in a chlorine room should
be NEMA 4X (corrosion resistant).
[Note: These general sanitary deficiencies on
chemical feed systems are applicable to all feed
systems used for any and all chemicals employed
in the treatment process.]
Turbidity Removal
Purpose of Treatment
According to the SWTR, all community and non-
community public water systems that use a surface
water source or a ground water source under the
direct influence of surface water must meet certain
criteria for the removal or inactivation of Giardia
cysts and of viruses. For surface water systems
required to filter, the removal of turbidity by one of
the treatment processes is a key step in complying
with these requirements. In recent years, outbreaks
caused by Cryptosporidiurn in the United States
have prompted recommendations from EPA and the
American Water Works Association (AWWA) to
achieve turbidity removals well beyond the levels
required by the SWTR's performance standards as
measured in the combined filter effluent. This goal
encourages direct and conventional filtration plants
to be optimized to achieve maximum turbidity
removal efficiency and to keep the effluent from
each individual filter below 0.1 NTU at all times.
Conventional Treatment
STATIC MIXER
(COAGULATION)
OR
FLASH MIX
CHEMICAL CHAMBER FLOCCULATION
FEED
6-16
-------
Chapter 6 - Water Treatment Processes
Treatment Processes
Conventional Treatment. The most widely used
technology for removing turbidity and microbial
contaminants from surface water supplies includes
coagulation, flocculation, and sedimentation,
followed by filtration. Conventional treatment
plants typically use aluminum or iron compounds
in the coagulation processes, but polymers may
also be used to enhance coagulation and filtration.
Generally, gravity filters with sand, dual, or mixed
media filters are used. The filtration rates may be
Direct Filtration
STATIC MIXER
(COAGULATION)
OR
FLASH MIX
CHEMICAL CHAMBER
FEED
FINISHED
WATER
Direct Filtration Package Plant
I pH ADJUSTMENT
I STATIC MIXER!' ^1 RAW WATER]
from 2 gpm/ft2 with sand as the single medium up
to 6 gpm/ft2 for dual and mixed media filters.
Direct Filtration. This process is similar to
conventional treatment, except sedimentation is
omitted. Direct filtration generally consists of
coagulation, flocculation, and filtration using dual
or mixed-media filters. A variation of this process,
which may be called "in-line filtration," includes
only filters preceded by chemical coagulant
application and mixing. Direct filtration is best
suited to systems that have high quality and
seasonally consistent influent
supplies. The influent generally
should have turbidity of no more
than 10 NTU and color of less
than 30 units.
Packaged Filtration. This
technology generally includes the
processes found in a
conventional treatment plant.
The unit processes are combined
in a package by an equipment
supplier and can be delivered to
a site where a simple hook up of
pipes is all that is necessary to
provide treatment. Package
filtration may be cost effective
for small communities but,
contrary to some literature,
requires skilled operators to
achieve consistent performance.
This is particularly true when the
raw water is susceptible to rapid
changes in quality.
Each of the three treatment
processes discussed above
depends on the operators
successfully providing
coagulation and flocculation of
the particles in the raw water. As
discussed earlier, coagulation
and flocculation are chemical
and physical processes to
improve the particulate and
colloid reduction efficiency of
subsequent settling or filtration
processes. Coagulation involves
feeding chemicals to destabilize
the similar charges on suspended
particles, allowing them to
coalesce and thereby begin to
form floe. This process is very
6-17
-------
How to Conduct a Sanitary Survey
Conventional Treatment Package Plant
LEHA.PJUSTMENT
I STATIC MJXER
the inspector should observe the
operator's level of skill and
understanding.
difficult to control with surface waters of changing
turbidity, temperature, alkalinity, and color.
Flocculation, which partly overlaps the coagulation
process, requires gentle mixing of destabilized
particles to form floe that can settle, or be filtered,
ou, of the water. The inspector must be able to 3.
determine if the operators are using proper process
control procedures to ensure removal of turbidity
and associated pathogens. A careful review of the
system's operating records and logs will help make
such determinations.
Sanitary Deficiencies -
Conventional Treatment
Coagulation - Rapid Mix
[Note: The sanitary deficiencies related to
chemical feed systems earlier in this chapter 4.
should also be applied to this section.]
1. Is a coagulant used at all times the plant is
in operation?
The inspector should ask if a coagulant is
always added when the plant is in operation. If
a coagulant is not being added, the state
primacy agency should be notified immediately
because it may want to issue a boil water
notice. The inspector should check that there
are redundant pumps for the primary coagulant
and polymers and that spare parts are
available. In answering the questions below,
2. What type and
combination of
coagulants are being
used?
Alum or ferric salts are used as
primary coagulants. The
effectiveness of alum decreases
when pH exceeds 8.0. Low
molecular weight cationic
polymers are also used as
primary coagulants. Typically
used with raw water that is low
in turbidity, they are more
applicable to direct filtration.
Polyaluminum chloride combines
alum and polymer so the operator adds only
one chemical. Nonionic and anionic polymers
are used as coagulant, flocculent, filter, and
backwash-water aids.
For what purpose is each coagulant
chemical used?
The operator should be able to fully explain the
purpose of each coagulant chemical and why it
is injected at a particular point. For example,
"This low molecular weight polymer which is
injected immediately downstream of rapid mix
is used as a coagulant aid, and this high
molecular weight polymer is added at a bend in
the pipe prior to the filters as a filter aid." Is
the plant adding too many coagulant
chemicals?
How is the dosage of each coagulant
chemical determined?
The inspector should determine whether the
operator uses a streaming current monitor, jar
tests, pilot studies or combinations of such
tests to determine dostige. Ask the operator to
show you how to make up stock solutions for
jar tests for both alum and polymers, how to
run and dose ajar test, how to calculate iiiL/
min from mg/L, how to calibrate the feed
pump, and how to prepare the proper dilution
for day tanks. An operator unable to perform
these routine operations likely does not have
the advanced skill needed to run rapid sand
6-18
-------
Chapter 6 - Water Treatment Processes
filtration. Typical filter aid dosages range from
0.02 to 0.1 mg/L, and backwash water dosages
range from 0.1 to 0.15 mg/L. Since polymers
typically neutralize the charges on particles, it
is easy to overdose.
5. Is there a process control plan for
coagulation addition?
What type of process control plan has been
developed to control chemical dosages during
routine and emergency levels of raw water
turbidity or other water quality problems?
Does the system have shortened filter runs due
to filter-clogging algae, and what is done to
control this and other special problems? Does
the system respond to changes in raw water
quality with changes in process control in order
to keep the quality of finished water high?
6. Is the rapid mix process adequate?
The rapid mix process is a critical part of the
coagulation process. Mixing can be
accomplished by several means, such as
mechanical units, diffusers, in-line mixers, and
baffles. The inspector should note the type of
mixer and determine if the mixing equipment is
functioning properly for all flows and all
ranges of coagulant. Inadequate mixing can
severely affect the performance of downstream
processes, particularly when raw water quality
is deteriorating.
Flocculation
1. Is the flocculation process adequate?
Problems with short circuiting in the
flocculation basin should be noted. The
inspector should observe if there is good floe
formation at the effluent end of the flocculation
basin prior to entry into the sedimentation
basin. The best floe size may range from
approximately 0.1 mm to 3.0 mm, depending
on the characteristics of the treatment plant.
The paddles of mechanical flocculators should
be in place and turning properly.
Sedimentation
1. Is the sedimentation process adequate?
The inspector should describe the
sedimentation process (e.g., tube settlers,
lamealla plates) and note problems with short
circuiting or excessive turbulence.
For upflow-solids-contact clarifiers, the mixer
must remain in operation to keep the blanket in
suspension when the unit is shut down.
There should be little or no carryover of floe
from the sedimentation basin to the filters. As a
rule of thumb, the coagulation, flocculation,
and sedimentation processes are functioning
properly if the turbidity of the effluent of the
sedimentation basin is monitored every 4 hours
and measures less than 2 NTU. The inspector
may want to calculate the surface overflow rate
under peak flow conditions and compare the
calculated value with the state's design
standards. The inspector should determine if
sludge removal is adequately addressed in the
plant's operational procedures. Those
procedures should include removal of sludge
from the sedimentation basins and ultimate
sludge disposal from the treatment plant.
Filtration
1. Is the filtration process performing
adequately?
The primary purpose of filtration is to remove
suspended solids. Filter performance can be
measured by the reduction in turbidity through
each filter. The inspector should be concerned
with the turbidity removal characteristics of
each filter in service.
2. Is there adequate pre-treatment?
The quality of water entering the filters must
be monitored to ensure that the filter is
performing according to design guidelines. The
filtration process, regardless of type, cannot
perform effectively if the influent's
characteristics are unacceptable. [Note: This
condition is also critical in systems such as
slow sand, diatomaceous earth (DE), and
membrane filtration.]
6-19
-------
How to Conduct a Sanitary Survey
3. Are there rapid fluctuations in the flow
through the filter?
Rapid changes in flow can cause breakthrough.
The inspector should record causes of rapid
flow fluctuations, e.g., operation procedures,
recycling of backwash water, or a cycling rate
control valve.
4. What control and assessments are used to
evaluate the performance of each filter?
The inspector should determine what methods
are used, such as continuous turbidity and
other monitoring, to evaluate performance,
including raw and settled water turbidity, pH,
alkalinity, and hardness. Also determine the
frequency of the evaluations. Systems covered
by the IESWT Rule and LT1 must
continuously monitor the turbidity of each
individual filter and keep a record of the
measurements taken at 15 minute intervals.
The inspector should request those records and
inspect them to make sure the filters are
operating properly and that the system has not
exceeded triggers which would require follow-
up action.
5. Are instrumentation and controls for the
process adequate, operational, and in
service?
Because turbidimeters must be extremely
accurate, they should be calibrated (secondary
and primary standards) regularly according to
manufacturer's recommendations. Head loss
through the filter is also important to filter
operation, as is the use of rate of flow
controllers. The instruments for these
measurements and controls should be
functioning properly. The inspector should
determine if proper filtration and backwash
rates are used where applicable. If the filter-to-
waste option is available at the plant, the
inspector should ensure that it is used properly
and that testing is done to check the adequacy
of the procedure. The operator should be able
to explain the significance of the readings
obtained from the instrumentation at the
facility.
6. Are the filters and related equipment
operated properly and in good repair?
Is there sand in the clearwell indicating
underdrain failure or severe media problems?
Are backwash pumps operated at too low a
rate, leading to mudballs and short-circuiting,
or at too high a rate, which will wash the media
out of the filter. Is the surface wash operated to
break up the mat on top of the filter? Is the
media checked for the accumulation of mud on
the surface and mudballs within the media? Is
the top layer of sand manually cleaned
regularly if mud accumulation is a problem? Is
the media expansion during backwash adequate
at all water temperatures? Is the backwash rate
increased and decreased slowly to avoid
damaging the filter? Is the media probed to
check for adequate media depth and to find
uneven gravel levels or dead spots where
damage to the underdrain is not allowing bed
expansion? During operation, are there
depressions, cracking, or other indications of
short-circuiting in the media? Is there filter-to-
waste capability and is it used? Does the
system have a maintenance plan for the filter
and all related appurtenances?
Pressure filters are a special concern due to the
difficulty of opening the bolted hatch for
inspection and assessment; the inspector should
ask when the hatch was last opened and the
filter inspected for the above items.
7. What initiates a backwash, and is there an
SOP in place?
Backwashing may be initiated due to head loss,
time, or effluent turbidity. It is important that
all the operators of a system use the same
criteria. In addition, the system should have a
written standard operating procedure for
backwashing and for returning the filter to
service to ensure that all staff do these tasks in
the same way.
The inspector should check how backwash
water is disposed of to ensure compliance with
state and federal regulations and to determine
its impact on the treatment process. Research
shows that recycling backwash water may
concentrate Giardia cysts, Cryptosporidium
oocysts, and disinfection byproducts.
Equalization or treatment of backwash water
6-20
-------
Chapter 6 - Water Treatment Processes
and other recycle streams prior to their
injection at the plant headworks helps minimize
these risks. The inspector should check to
ensure the system's compliance with the Filter
Backwash Recycling Rule.
The inspector needs to have the operator
backwash a filter during the sanitary survey, if
feasible, in order to determine the existence of
any of the conditions noted above. The
inspector should also examine preventative
maintenance and repair records.
8. If the plant is a conventional plant, is it
meeting the disinfection byproduct
precursor removal requirements of the
Stage 1 Disinfectants/Disinfection
Byproducts Rule?
The inspector should review the system's
operating records and quarterly reports to the
state to make sure adequate TOC is being
removed in compliance with the Stage 1 DBF
Rule. The inspector should request a copy of
the system's State 1 DBF Rule monitoring plan
and review it as well.
9. Was the system required to prepare a
disinfection profile? Is the profile available
for review?
The inspector should review the system's
disinfection profile on site and check to ensure
that adequate CT is available to meet the
removal/inactivation requirements of the
SWTR. Any planned or potential changes in
disinfection practices should be discussed.
Slow Sand Filtration
This process consists of a single
medium of fine sand
approximately three to four feet
deep. The medium is not
backwashed as it is in a rapid
sand filter; instead, it is cleaned
manually by removing the
surface of filtration medium.
communities, but must include adequate (physical,
not chemical) pre-treatment. They are not suitable
for raw water with high turbidities and rapidly
changing quality. These filters are operated under
continuous submerged conditions. They function
using biological mechanisms (schmutzdecke) and
physical-chemical mechanisms.
Sanitary Deficiencies - Slow Sand
Filtration
1. What pre-treatment is used, if any?
Because chemical pre-treatment with a
coagulant is not needed and not recommended
due to filter clogging, what pre-treatment, if
any, is used? Is a screen, chlorine, or a
roughing filter (coarser sand) used prior to
slow sand?
2. What method is used to clean the slow
sand filters?
What is the average and worst case time
between cleaning the filters? Is cleaning
accomplished by scraping (the most common
method) or by harrowing (low backwash rate
while turning the medium)? What is the sand
depth? New sand should be added when the
depth approaches 24 inches.
3. Are there redundant slow sand filters?
Slow sand filters perform poorly for 1 or 2
days, and sometimes up to 2 weeks, after being
cleaned. Therefore, it is essential that the
facility have redundant units with a filter-to-
waste cycle to allow the filter to build up a
biological mat. Filters can be returned to
service sooner when the harrowing technique of
Slow sand filters operate in the
range of 0.03-0.10 gpm/ft2, and
therefore require extensive land
area. These filtration systems
may be appropriate for small
Slow Sand Filter and Schmutzdecke
\ TAILWATER ]
6-21
-------
How to Conduct a Sanitary Survey
cleaning is used. Slow sand depends on
microbes, and their worst enemy is the lack of
moisture. The inspector should ask if the filter
is ever left unsubmerged and, if so, for how
long.
4. Is the slow sand filter covered and light-
free?
Slow sand filters should be enclosed in a
building so they can be cleaned and so ice
buildup during the winter can be avoided. The
housing should also be light free to eliminate
algae growth.
Diatomaceous Earth (DE) Filtration
DE filtration, also known as precoat or diatomite
filtration, is appropriate for direct treatment of
surface waters to remove
relatively low levels of turbidity
and microorganisms. Diatomite
filters consist of a layer of DE
(about 1/8-inch thick) supported
on a septum or filter element.
Septa may be placed in pressure
vessels or operated under a
vacuum in open vessels. Units
are generally designed for a
filtration rate of 1 gpm/ft2.
2. Is the flow interrupted?
Interruptions of flow cause the filter cake to
fall off the septum, allowing pathogens to pass
through the DE filter. (For this reason, DE is
not a recommended technology for on/off
operation.) Is the precoating reapplied any time
flow is interrupted at this facility?
3. When is backwashing initiated?
The rate of body feed and size of the media are
critical for determining the length of the filter
run. Filter runs typically range from 2 to 4
days. Shorter runs minimize filtered water taste
and odor problems arising from the
decomposition of organic matter trapped in the
filter. DE is effective for removing algae, but if
prechlorination is used, increased taste and
Sanitary Deficiencies -
Diatomaceous Earth
Filtration
Diatomaceous Earth Filtration
1. What levels of precoat and continuous
body feed are added?
The minimum amount of filter precoat should
be 0.2 lb/ft2, and the minimum thickness of
precoat should be 0.5 cm to enhance cyst
removal. DE filters do not need a filter-to-
waste cycle because of the precoat process.
What amount of precoat is used?
Continuous body feed is required because the
filter cake is subject to cracking. Also, if there
is no body feed there will be a rapid increase in
headloss due to buildup on the surface. What
dosage is used for body feed and is it
continuously added? Can the operator verify
the dosages?
odor can be expected. The inspector should
determine whether this facility has taste and
odor problems that are attributable to long
filter runs or prechlorination? How often is the
septum inspected and cleaned (~ 100 filter
runs)? How is the spent filter cake disposed of?
Bag and Cartridge Filtration
Bag and cartridge filters use filter elements
(ceramic, paper, or fiber) with pore sizes as small
as 0.2 jam. This pore size may be suitable for
producing potable water from raw water supplies
containing moderate levels of turbidity, algae, and
microbiological contaminants. The advantage to
small systems of these rnicroporous filters is that
no chemicals, other than the disinfectant, are
required. The use of this type of filtration should be
limited to low-turbidity waters (<5.0 NTU)
6-22
-------
Chapter 6 - Water Treatment Processes
because of susceptibility to rapid headloss
buildup. Many installations address this problem
by installing sand or dual media pressure filters,
without coagulation, for pre-treatment.
Sanitary Deficiencies - Bag and
Cartridge Filtration
1. What type of pre-treatment is used?
Bag and cartridge filters can be used on raw
water of any quality depending on the degree of
pre-treatment that is provided. The inspector
should describe the pre-treatment that is used
at the facility and whether the bag and
cartridges are used as the primary treatment or
to provide an extra level of physical removal to
ensure public health protection (for example,
filters added after a poorly performing
conventional treatment pi ant).
2. What is the micron rating for the final
unit?
There should be at least two stages of
filtration, the first using a 10 micron or larger
pore size and the second using a 1 to 5 micron
pore size. The inspector should verify through
the labeling on spent filters or manufacturers'
invoices that the second filter has not been
replaced by one with a larger pore size because
the filter runs were too short. If the pore size of
the second filter is not in the 1 to 5 micron
range, pathogens can pass through the filter,
resulting in a serious public health concern.
3. What are the average and the shortest
times between filter replacements?
Depending on site-specific conditions, these
filters show excellent to poor turbidity
reductions when used with turbid raw water of
less than 10 NTU. Some bags will last only a
few hours when turbidity exceeds 1 NTU. The
inspector should ask the operator what
seasonal site-specific conditions may shorten
filter runs. The inspector should also ask
whether the facility can meet the turbidity
standard for finished water at all times. Is bag
replacement so frequent that upgrades to the
pre-treatment are justified? The inspector
should make sure the system never operates
without the filter cartridges or bags in place.
Some small systems have been known to
Bag and Cartridge Filtration
remove them when turbidity necessitates
frequent change out.
4. Is there a manufacturer's challenge for
Giardia removal for the filter and housing
being used?
To optimize filter run time, operators may have
experimented with different filters from various
manufacturers. Different filters may not be
compatible with the original housing,
jeopardizing the seal and allowing pathogens to
pass through the filter. The inspector should
check that the housing and filter currently
being used are the same ones that were used in
any challenge study that is on record at the
plant. If they are not the same, the inspector
should bring this to the attention of the state,
which may want to perform a new challenge
study. Otherwise, are there any filter integrity
tests required by the state and have they been
performed?
Membrane Filtration
The membrane filtration process involves passing
water at high pressure through a thin membrane of
hollow-fiber or spiral-wound composite sheets.
Microfiltration can remove bacteria, Giardia, and
some viruses. Membrane filtration may be
attractive for small systems because of its small
size and because it does not require chemical
coagulants. Periodic chemical cleaning is required
and the resulting product requires proper disposal.
Membranes can be grouped into the four categories
described below. The selection of a membrane is
based on site specific treatment goals (for example,
inorganics removal, natural organic matter
6-23
-------
How to Conduct a Sanitary Survey
removal, paniculate removal or pathogen
removal).
Membrane Core
I
The advantage of membranes is that filter quality is
achieved regardless of changes in turbidity,
microorganism burden, algae blooms, pH,
temperature, or operator interaction. Instead of
compromising the quality of finished water,
membrane systems lose operational performance,
such as increasing pressure differentials across the
membrane and shortening of the time between
cleanings. The necessary level of operator skill is
classified as basic, except for reverse osmosis,
which is classified as high because of the high level
of pre-treatment needed. Fouling and scaling of the
membranes are the main concerns, especially for
high-pressure membranes.
Reverse Osmosis (RO). RO uses high pressure to
remove salts from brackish water and seawater. It
excludes particles less than 0.001 microns in size.
RO is an absolute barrier for cysts, bacteria, and
viruses. Because it is used for very specific water
quality problems, RO is discussed in more detail
under Speciality Treatments in this chapter.
Nanofiltration (NF). NF is also called membrane
softening and low pressure RO. It is effective in the
removal of calcium and magnesium ions
(multivalent cations or hardness). NF is the most
efficient membrane for removing natural organic
matter to control disinfection byproducts (DBFs).
It excludes molecules larger than 0.001 microns,
the organic compound range, and is an absolute
barrier for cysts, bacteria, and viruses.
Ultrafiltration (UF). UF uses low-pressure
membranes to remove natural organic matter and
particulates. UF excludes molecules larger than
0.01 microns, the molecular/macromolecular range,
and is an absolute barrier to cysts. It provides
partial removal of bacteria and viruses.
Microfiltration (MF). MF uses low-pressure
membranes to remove particulates and suspended
solids. MF excludes molecules larger than 0.1
microns, the macromolecular/microparticle range.
It is an absolute barrier to cysts and provides
partial removal of bacteria and viruses.
Sanitary Deficiencies - Membranes
[Note: The sanitary deficiencies related to
chemical feed systems earlier in this chapter
should also be applied to this section.]
1. What type of membrane is used, and what
is its intended purpose?
The inspector needs to identify which of the
above categories of membranes is being used
and why it was selected. For example, NF may
have been chosen to remove the organic
compounds that are precursors to DBFs.
2. What type of pre-treatment is used?
A 500-micron screen is usually the only pre-
treatment needed for MF. For RO and NF
systems to operate economically, suspended
solids, microorganisms, and colloids have to be
removed before these technologies can
effectively remove dissolved contaminants. MF
is the best pre-treatment for RO and NF. The
inspector should describe what pre-treatment is
performed prior to the final membrane.
3. What safeguards exist to warn operators
of membrane failure?
Membranes provide a very effective barrier to
pathogens, depending on which membrane is
used. However, membranes are only a single
barrier. If that barrier fails, pathogens are not
removed by any other means. Some membranes
have TDS meters, others have automatic
membrane integrity tests to determine the
integrity of the membrane; an integral module
will exhibit little, if any, decay over the test
period. The inspector should discuss what type
of membrane integrity test is used and what is
done if the test shows the membrane is failing.
6-24
-------
Chapter 6 - Water Treatment Processes
Are redundant units available in case one of
the units fails, is being cleaned, or is
undergoing membrane replacement?
4. What are the fouling rate and life of the
membranes?
Fouling can be controlled by pH adjustments
and the degree of pre-treatment provided. The
smaller the pore size of the membrane, the
greater the concerns about fouling. For MF, pH
adjustments are not needed since MF does not
remove uncomplexed dissolved ions. Generally,
a silt density index of less than 1.0 means that
the fouling potential is low. The inspector
should describe the fouling problems that the
facility experiences and how they affect
membrane life.
5. What is the percentage recovery and what
technique is used for backwash?
The inspector should determine the percentage
recovery (the percentage of raw water that
actually makes it through the membrane) for
the membranes used at the facility. For
example, the recovery for MF is approximately
90 percent. The inspector should also discuss
how backwashing is accomplished (for
example, gas backwash), how often it is
performed, and how the raw water quality
affects the volume required. For example, the
backwash volume for MF is approximately 6
percent for low turbidity water and up to 12
percent for high turbidity water.
6. What is the frequency of cleaning and
disposal of cleaning fluids and brines?
How often do the membranes require cleaning?
The inspector should describe what chemicals
are used and how the system disposes of them.
Several methods are available to dispose of the
brine: sanitary sewers, surface water streams,
lagoons or holding ponds, land application, and
recycling back to the headworks. How is the
brine disposed of at this facility? The inspector
should check to see that the brine is properly
disposed of. Some contaminants, if present in
high concentrations in the raw water, may
create a brine that is a hazardous waste.
7. What is the condition of the plant, gauges
and appurtenances?
Membrane plants are mechanically complex
and have many automatic valves and many
more connections that require o-rings to
achieve a tight water seal. The inspector should
determine whether all the valves are operating
properly and whether there are leakage
problems throughout the piping network.
Corrosion Control
Corrosion causes the deterioration of pipe
materials. It generally occurs in drinking water
distribution systems by the principle mechanism of
dissolution. The dissolution of pipe materials
occurs when favorable water chemistry and
physical conditions combine.
Need for Treatment. Altering water quality
characteristics through treatment can extensively
reduce some forms of corrosion activity, but may
have less significant effects on others. Many public
water systems must implement optimal corrosion
control treatment to meet the lead and copper
action levels established by the federal Lead and
Copper Rule.
Corrosion Control Treatment. Corrosion control
treatment is principally intended to inhibit
dissolution. The objective is to alter the water
quality so that the chemical reactions between the
water supply and the pipe materials favor the
formation of a protective layer on the interior of the
pipe walls. Corrosion control treatment attempts to
reduce the contact between the pipe and the water
by creating a film that is:
Present throughout the distribution and
home plumbing systems.
Relatively impermeable.
Resistant to abrupt changes in velocity.
Less soluble than the pipe material.
Corrosion control technologies can be
characterized by two general approaches to
inhibiting lead and copper dissolution:
6-25
-------
How to Conduct a Sanitary Survey
Precipitation of insoluble compounds on the
pipe wall as a result of adjusting the water
chemistry.
Passivation2 of the pipe material itself
through the formation of less soluble metal
compounds (carbonates or phosphates) that
adhere to the pipe wall.
In general, the available corrosion treatment
technologies are precipitation by calcium hardness
adjustment and passivation by pH/alkalinity
adjustment or the addition of a corrosion inhibitor.
Sanitary Deficiencies - Corrosion
Control
[Note: The sanitary deficiencies related to
chemical feed systems earlier in this chapter
should also be applied to this section.]
1. What are the results of current lead and
copper sampling?
Depending on whether the lead or copper
action levels were exceeded, the results may
indicate different corrosion control strategies.
2. What are the characteristics of the water
entering and leaving the treatment plant?
The operator should be able to provide test
data that indicate the chemical characteristics
of the water entering and leaving the treatment
plant. These data should be the basis for
developing an appropriate corrosion control
program and for demonstrating that the
chemicals being applied are accomplishing the
desired goals.
3. What sampling is conducted in the
distribution system as part of the
corrosion control program?
Appropriate sampling in the distribution
system must be done to ensure the desired
results and to prevent problems possibly
associated with overfeeding chemicals. For
example, excessive feeding of a phosphate
2Passivation is a generic term referring to the
process whereby a surface becomes covered with a
dense protective layer that serves to protect the
surface from corrosion.
inhibitor could encourage the growth of
undesirable biological slimes in the distribution
system piping.
4. Is the test equipment to monitor the data
appropriate and in good working order?
Since pH is generally a critical parameter in
corrosion control, the test equipment must be
accurate and properly calibrated.
Iron and Manganese Removal
Iron (Fe) and manganese (Mn), which comprise
approximately 5 percent and 0.1 percent,
respectively, of the earth's crust, are found widely
distributed in surface and ground waters in nearly
all geographic areas.
Fe and Mn in Surface Water. Iron and manganese
may be present in surface water due to their
dissolution from the associated geologic formations
or from the decomposition of organic materials.
Nearly all of the available methods for iron and
manganese removal, except ion exchange, rely on
the oxidation of the soluble forms to insoluble
forms along with or followed by clarification or
filtration to remove the resulting precipitates.
Therefore, the processes discussed in the section on
surface water treatment (pre-treatment, chemical
addition, coagulation, flocculation, sedimentation,
and filtration) will generally be adequate to deal
with iron and manganese problems in surface
water.
Fe and Mn in Ground Water. In ground water,
iron and manganese are found particularly in the
ground water drawn from underground formations
of shale, sandstone, and alluvial deposits. Iron in
ground water is normally in the range of a few
hundredths to about 25 mg/L, with the majority of
wells drawing water in which the Fe concentration
is less than 5 mg/L. Manganese is usually present
in ground water in a concentration less than 1 mg/
L, although in some places manganese levels have
been significantly higher.
Treatment Processes. Processes for removing iron
and manganese from ground water will generally
be one of the following:
Oxidation (aeration, chlorination, or
potassium permanganate) followed by
filtration.
6-26
-------
Chapter 6 - Water Treatment Processes
Aeration - Filtration
Chlorine Oxidation - Filtration
TREATED
WATER
TO
CLEAR
WELL
L^ATJCMIXERJ 1 RAW WATER
6-27
-------
How to Conduct a Sanitary Survey
Ion Exchange
-------
Chapter 6 - Water Treatment Processes
Manganese Greensand Filtration
Intermittent Regeneration (IR) Process
Oxidation, clarification, and filtration.
Ion exchange.
Manganese greensand filtration.
Application. The applicability of each of the above
processes and the sequence of chemical addition
depends on the raw water quality and plant
capacity at each water treatment facility. For
specific information on the design and operation of
each of these processes, consult the suggested
references at the end of this Guide.
Sanitary Deficiencies - Iron and
Manganese Removal
[Note: The sanitary deficiencies related to
chemical feed systems earlier in this chapter
should also be applied to this section.]
1. What treatment process is used?
A number of processes, as well as variations
on some of the standard processes, are
available for iron and manganese removal. The
operator should be able to describe the process
used and why the plant is operating in that
particular mode.
2. Is the process performing adequately
based on visual observation?
The inspector should examine the filtered water
to determine if any color is evident. Discolored
finished water could indicate iron or
manganese breakthrough or an overdose of
potassium permanganate, which could result in
water with a pink color.
3. What chemicals are used and in what
amounts?
In a manganese greensand filtration plant, the
operator may be using some combination of
chlorine, potassium permanganate, and a
chemical for pH adjustment (caustic soda, soda
ash, or lime). The quantity of each chemical is
critical to consistent plant performance.
4. Where are the chemicals applied?
The sequence of chemical addition in a
manganese greensand filtration plant will
6-29
-------
How to Conduct a Sanitary Survey
greatly influence the effectiveness of the
system in removing iron and manganese. The
inspector should determine whether the plant
is being operated in the CR (continuous
regeneration) mode or IR (intermittent
regeneration) mode and should determine the
justification for the mode being used.
Generally, the CR mode is applied where iron
removal is the main objective, with or without
the presence of manganese. The IR mode is
used when the water contains all or mostly
manganese, with lesser quantities of iron.
When polyphosphate is used to sequester lower
concentrations of the metals, the inspector
should check to be sure the sequestering agent
has sufficient time and mixing prior to chlorine
addition.
Organics Removal
A number of methods including granular activated
carbon, powdered activated carbon, aeration, and
enhanced coagulation are commonly used to
remove organic substances from drinking water.
Carbon Absorption
Carbon absorption is primarily used to reduce
organics that contribute to taste and odor and to
reduce organics that contribute to THM formation,
some of which may be carcinogenic.
The two forms of activated carbon used in the
water works industry are powdered activated
carbon (PAC) and granular activated carbon
(GAC).
PAC. Powdered activated carbon is less than 0.1
mm in diameter. One gram of PAC contains 500 to
600 square meters of surface area. PAC weighs
approximately 20 to 45 pounds per cubic foot
(0.32 - 0.72 g/cm3).
Use: PAC is primarily used to remove taste
and odor caused by organic compounds. It
can also be used to aid flocculation. Because
of its high density, PAC helps to form the
nuclei of the floe particles.
Feeding: PAC is commonly delivered to the
site in 5-pound bags. It can be fed dry or as
a slurry. The most common method of
application is the use of special dry chemical
feeders where it is mixed into a slurry
containing approximately 1 pound per
gallon. This solution is then fed to the plant
flow. Because PAC can be fed from a
chemical feeder, it is more effective than
GAC when the concentration of the organics
varies. However, the PAC addition must be
followed by filtration to remove the carbon
before it enters the distribution system.
Handling: PAC requires special handling
and storage. Because PAC produces large
amounts of fine powder, it is highly
combustible and explosive.
Contact Time: The ability of PAC to do its
job is based on contact time and
concentration. The most important of these,
however, is contact time. Because PAC
absorbs chlorine, it loses its effectiveness if
fed in after the introduction of chlorine.
Effectiveness: For best results in reducing
taste and odor and in absorbing the
precursors to THMs, PAC should be fed
into the raw water at the front end of the
plant prior to the introduction of C12, with a
lesser dosage fed just prior to filtration.
GAC. Granular activated carbon ranges from 1.2
to 1.6 mm in diameter. One gram of GAC contains
650 to 1,150 square meters of surface area. GAC
weighs approximately 26 to 30 pounds per cubic
foot (0.42 -0.48 g/cm3).
Use: GAC is primarily used to remove
organic compounds, which may be
associated with taste and odor production,
and to prevent the formation of THMs when
the concentration of the organics is constant.
It also can be used to remove disinfection
byproducts after they are formed and to
remove VOCs and SOCs. GAC does not
require post-treatment filtration.
Bag Sizes: GAC is delivered to the site in
60-pound bags or in bulk. It is used as a
filter medium or placed in columns called
contactors.
Filter Placement: When placed in a filter,
GAC should be at least 24 inches deep. The
placement of GAC in a typical filter can
enhance turbidity removal. A common
6-30
-------
Chapter 6 - Water Treatment Processes
filtration rate for a GAC filter is 2 gpm/ft2.
Life expectancy of GAC filters ranges from
up to 3 years for taste and odor removal to
as little as 1 month for THM removal. Due
to GAC's lower specific gravity,
backwashing procedures must be changed
when GAC is placed in filters.
Contactor Beds: GAC contactors are
composed of beds of GAC at least 3 feet
deep. The beds are often placed in parallel
operation so that one can be replaced while
the second is being used. Alternatively,
columns may be placed in series so that the
contaminant is entirely contained within the
downstream column after the lead column
has been saturated. When the activated
carbon is replaced in the upstream column,
the flow is reversed so it goes through the
freshest column last. This arrangement helps
maximize the use of carbon.
GAC contactors are used when the life
expectancy of the GAC is only a few
months. It is easier to change the GAC than
to change a filter bed. GAC contactors are
commonly placed in the system after
filtration. GAC contactors are commonly
sized based on empty bed-contact time and
regeneration frequency.
Sanitary Deficiencies - Organics
Removal
[Note: The sanitary deficiencies related to
chemical feed systems earlier in the chapter
should also be applied to this section.]
Activated Carbon
1. Why is activated carbon used?
There should be some documentation of the
need, such as an engineering study or a
management decision. The reasons could
include taste and odor, THM, or the removal of
organics. In any case, there needs to be a
defined reason for the use of activated carbon.
2. Which process is being used?
Is the PAC or GAC process used? It is
important to remember that PAC is most
effective when the concentrations of the
contaminants vary.
3. What testing is performed to determine the
effectiveness of the activated carbon?
The testing should be directly associated with
the defined need for activated carbon. Small
systems may not be testing for THMs.
However, if the presence of THMs is what
caused them to use activated carbon, they
should test for its effectiveness. Often, GAC
beds are placed in the filter to solve a problem
and then forgotten. Thus, they can become
ineffective without the operator knowing it.
If PAC is being fed:
1. Have they had any problems with black
water?
PAC will pass through some filter media,
especially pressure filters.
2. How often are the feeders calibrated?
Chemical feeders feeding PAC should be
calibrated with each new batch of PAC. The
feed rate should be checked by measuring the
output daily.
3. Do the operators have proper safety
equipment?
They should have dust masks, sealed safety
glasses, and shower facilities.
4. Is the PAC stored properly?
PAC is an explosive dust. Storage must include
an explosion-proof electrical system and
adequate ventilation.
When GAC is added to a filter:
1. Is the backwash adequate?
Check for the presence of mud balls, filter
surface cracking, or compaction.
2. What is the depth of the GAC?
Since it is lighter than most other media, GAC
can easily be washed away during the
6-31
-------
How to Conduct a Sanitary Survey
backwash process. The inspector should also
check to see that the carbon is replaced on a
schedule that ensures proper treatment.
When GAC contactors are used, what is the
empty-bed contact time and regeneration or
replacement frequency?
Aeration
Aeration is a process by which air and water are
brought into intimate contact with each other for
the purpose of transferring volatile substances to or
from the water. This process is primarily found at
ground water facilities. Aeration may be used to:
Reduce volatile organic compounds, radon
gas, and taste and odor-producing
compounds such as hydrogen sulfide.
Oxidize organic and inorganic chemicals
such as iron, manganese, and organic
matter.
Packed Tower Aeration. There are many types of
aeration devices. Of the aeration options available,
packed towers are becoming widely used to reduce
trace concentrations of VOCs. The object is to
contact a small volume of organic-contaminated
water with a large volume of contaminant-free air.
The tower is filled with packing material. A
common material is a plastic ball about the size of
a ping pong ball.
Water and Air Flow. Water is pumped to
the top of the tower and allowed to fall over
the balls. Air is pumped under pressure into
the bottom of the tower. The water flows
downward, and the air flows upward. Thus,
this arrangement is commonly referred to as
countercurrent tower aeration. The packing
material creates very fine droplets of water
in the downward flow. This aids in diffusing
dissolved gases into the upward flow of air.
Air-to-Water Relationship. The air-to-
water relationship typically ranges from 20
to 1 to 50 to 1 (air to water, volume to
volume).
Problems. There are two major problems
associated with this process: contamination
of the water from contaminated air and
violation of air quality standards in the
vicinity of the tower. (The output from the
tower contains a high VOC level.)
Sanitary Deficiencies - Aeration
1. What type of aeration system is used?
Different types of units (cascade, tray,
mechanical, packed tower, spray) are used,
depending on the purpose of treatment. The
operator should be able to explain the reason
for the type of system in place.
2. What parameters are monitored to
evaluate the performance of the process?
The efficiency of the tower should be evaluated
routinely. Failure to do so is an indication that
the tower may not be performing as designed.
The frequency with which evaluations of tower
efficiency are made must meet local and state
requirements for the facility. Inspectors should
check the frequency against their own
communications about this problem.
Parameters typically monitored include pH,
moisture, VOCs, odor, and color. When an
aeration tower is also used to reduce odor and
taste, methane may be released. If this is the
case, there should be a systematic monitoring
program to determine the level of methane in
the area.
3. What types of contaminants are in the
vicinity that could be pulled into the air
supply?
If the air intake is next to the chlorine room,
lime storage area, or in a dusty environment,
the water supply may become contaminated.
4. What types of operational problems has
the facility experienced that could
contribute to poor performance of the
aeration device?
Typical problems include plugged nozzles on
the air system, algae and other biological
growth on the media, failure of the air blower,
and breaking up of the floe, which causes high
floe carry-over onto the filters.
6-32
-------
Chapter 6 - Water Treatment Processes
5. After treatment in the aerator, is the
effluent disinfected adequately before it is
introduced into the water distribution
system?
Contamination by wind-borne pollutants and
biological growth in the packing material
requires diligent post-treatment disinfection.
6. What is the condition of the aerator, both
inside and out?
If the aerator is not accessible for close
examination, the inspector should review the
maintenance records to determine the status of
the equipment.
Water Softening
Purpose. The primary purpose of water softening
is to reduce the content of dissolved minerals,
particularly calcium and magnesium, in order to
minimize the tendency of scale to form.
Softening hard water may provide additional
benefits, such as:
Biological growth control.
Enhancement of use for boiler feed and
cooling processes.
Removal of many trace inorganics.
Organics (i.e., disinfection byproducts
precursor) removal.
Description
Soft
Moderate
Hard
Very Hard
Hardness (mg/L
0-75
75 - 1 50
150 -300
Above 300
of CaCO3)
Softening water may also have the following
negative results:
The plant effluent pH of a lime soda
softening facility is usually about 8.9. AtpH
7.5, only one-half of the chlorine residual is
hypochlorous acid. At pH 8.9 it is down to
approximately 10 percent. This means that
the disinfection capabilities are reduced.
Definitions Pertaining to Softening
Hardness
Calcium
Hardness
Magnesium
Hardness
Total
Hardness
Carbonate
Hardness
Non-Carbon-
ate Hardness
Alkalinity
Calcium
Carbonate
(CaC03)
Equivalent
A characteristic of water
caused by divalent metallic
cations, mainly calcium and
magnesium, but also strontium,
ferrous iron, and manganous
ions. These cations are
typically associated with
anions such as bicarbonate,
carbonate, sulfate, chloride,
and nitrate.
Hardness caused by calcium
ions (Ca 2+).
Hardness caused by
magnesium ions (Mg 2+).
The sum of the hardness
caused by calcium and
magnesium.
Hardness caused by the
divalent metallic cations and
the alkalinity present in the
water, up to the level of the
total hardness.
That portion of the hardness in
excess of an amount equal to
the alkalinity.
The buffering capacity of water
to retard the change of pH; the
result of carbonate,
bicarbonate, hydroxide, and
occasional bicarbonate,
silicate, and phosphate;
commonly expressed as an
equivalent concentration of
calcium carbonate.
An expression of the
concentration of specified
constituents in water in terms
of their equivalent value of
calcium carbonate.
The water may become aggressive, thus
corroding metal pipes.
Disposal of the sludge is a problem.
THM levels may increase due to elevation of
the pH.
6-33
-------
How to Conduct a Sanitary Survey
Softening Processes
There are two common softening
techniques: lime soda and ion
exchange. Selecting a process is
based on a number of factors
associated with operating costs,
operating effectiveness, and
construction costs.
Lime Soda Softening. There are
three common lime soda
softening processes:
conventional, excess lime, and
split treatment.
Conventional
Removing Carbonate
Hardness. The lime soda
process is used to remove the
carbonate hardness by
precipitation. When magnesium
hardness is high, excess lime can
be fed to raise the pH and cause
the precipitation of magnesium
hydroxide. To reduce the pH and
make the water more stable, the
flow is treated with carbon dioxide in a process
called recarbonation. The amount of lime required
depends on the concentration of the hardness and
the type of hardness (calcium or magnesium). The
conventional lime soda process is used when there
is only a small amount of magnesium hardness and
excess lime is used when magnesium hardness must
also be reduced.
Removing Noncarbonate Hardness. In this
process, soda ash is added following excess lime
softening. This second step is effective in removing
noncarbonate hardness, but is not commonly used
because of the additional treatment units and
associated capital costs.
Split Treatment Process. The split treatment
process is an adaption of the excess lime process.
A portion of the water is treated and added back
into the untreated water to dilute it to the desired
level of hardness. This process reduces the amount
of chemical required to soften the water and thus
reduces operating costs.
Ion Exchange Softening. Ion exchange softeners
are primarily used in small ground water facilities
and in individual homes. They are composed of a
Ion Exchange Water Softener
(CI2)
FILTERED WATER |
pressurized vessel resembling a pressure filter.
The vessel is primarily filled with a resin like the
filter bed. The resin holds an excess of sodium
ions. These sodium ions are exchanged for
calcium and magnesium ions in the plant flow.
Once all of the sodium ions have been used, the
resin is regenerated with a brine solution and the
excess calcium and magnesium are removed. The
hardness of the effluent of this type of facility is
zero or near zero. Common ion exchange resins
include synthetic zeolites and organic polymers
(polystyrene resins).
Any water to be treated using the ion exchange
process must be relatively free of particulate matter
in order to prevent plugging the medium and
subsequent operational problems. Iron, manganese,
or other heavy metals, if present at high levels, may
cause problems with ion exchange resins by
binding permanently to the medium, thereby
reducing the exchange capacity over time. One
problem in the operation of an ion exchange system
is the disposal of spent brine from the regeneration
of the medium. Severe limits may be in place
relating to the proper discharge of this high salinity
water.
6-34
-------
Chapter 6 - Water Treatment Processes
Sanitary Deficiencies - Softening
[Note: The sanitary deficiencies related to
chemical feed systems earlier in this chapter
should also be applied to this section.]
Lime Soda Process
1. What are the treatment goals?
The staff should have finished water quality
targets for parameters such as pH, alkalinity,
and hardness. It is important that these targets
are clear to all staff in order to obtain optimum
plant performance.
2. Is the facility performing adequate process
control testing?
Testing at each stage of the process should
include at least the following process control
tests:
Alkalinity.
Hardness.
pH - carbon dioxide.
3. Is the facility tracking the chemicals used?
This process involves the use of a number of
chemicals that may have conflicting functions
and must be monitored carefully. For example,
too high a finished pH could cause disinfection
or disinfection byproduct problems.
4. Is the facility meeting the TOC removal
requirements (if applicable) of the Stage 1
DBF Rule?
Surface water systems that employ lime
softening must meet step 1 TOC removal
requirements. The inspector should check the
system's operating records and state reports to
make sure the system is in compliance.
Ion Exchange
1. What are the treatment goals?
This treatment process can reduce water
hardness to a very low level. This may result in
aggressive water quality that could contribute
to lead and copper problems in the distribution
system. The operators must understand the
implications of their treatment goals in light of
other possible problems.
2. What is the condition of the equipment?
The condition of the media is important and
must be monitored to ensure that fouling,
which will eventually affect the efficiency of
the process, is not occurring. Also, the overall
condition of the filter units and valves is
important to proper operation.
3. What is the operators' knowledge of the
softening process?
Because softening chemistry is typically more
complicated than other treatment processes, it
is normally not well understood. Operators
need to understand the softening process in
order to handle problems when they arise.
Chemistry training is available, and
management is responsibile for providing
this training to the operators.
Specialty Treatment
Reverse Osmosis
Principle of Reverse Osmosis
The Use. Reverse osmosis (RO) is used to
demineralize salt water, brackish water, and water
with concentrations of total dissolved solids
(TDS)from 100 to 8,000 mg/L. Its removal
(rejection) efficiency varies from a high of 90
percent on most TDS constituents to a low of 40
percent for mercury.
The Process of Osmosis. When a solution that has
a high TDS concentration is separated from a
solution of low TDS by a semipermeable
membrane, fluid will flow from the dilute solution
to the concentrated solution. This process is called
osmosis. The pressure caused by the difference in
concentration of the two fluids is called osmotic
pressure.
The Reverse Osmosis Process. Placing pressure
on the concentrated solution will force the fluid
backward through the membrane. The membrane
removes (rejects) the TDS in the concentrated
solution, thus producing fresh water from brackish
water. This process is called reverse osmosis.
6-35
-------
How to Conduct a Sanitary Survey
Equipment
A typical RO facility is
composed of the following
components.
Pump. A high pressure
pump (350 to 500 psi).
Membrane. The
membrane is commonly
made of cellulose acetate.
There are three common
types of membranes:
Spiral wound.
Pressure vessel.
Hollow fiber.
These membranes are
typically 1 OOF thick. One
side of the membrane has a dense layer
approximately 0.2F thick that is used to
reject the minerals. The remainder of the
membrane is a spongy, porous mass.
Acid Feed. An acid feed pump is used to
control the pH of the feed water. Sulfuric
acid is commonly used. It is normal for the
feed water to be adjusted to a pH of 5.5.
This low pH reduces the natural destruction
of the membrane (called hydrolysis) and
retards the buildup of calcium carbonate
scale on the membrane.
Scale Inhibitor Feeder. While pH
adjustment will control calcium carbonate
scale, it has little effect on calcium sulfate.
To control calcium sulfate, a polyphosphate
is commonly fed. Typically, sodium
hexametaphosphate (SHMP) at dosages of 2
to 5 mg/L is used.
Chlorinator. A chlorinator is used to
provide a 1 to 2 mg/L residual through the
unit in order to reduce bacterial growth in
the membrane.
Cleaning Tank, Pump, and Solution,
Typical cleaning solutions include citric
acid, sodium tripolyphosphate, B13, Triton
X-100, andEDTA.
Reverse Osmosis
11CONCENTRATED BRINJTj
Performance
The primary advantage of the RO process is that it
rejects a high percentage of dissolved solids from
the raw water. The rejection allows contaminated,
brackish, and saline water to be desalted for
potable use. Problems associated with RO plants
include:
High initial and operating costs.
Need for pre-treatment of turbid raw water
with acid and other chemicals to prevent
fouling of the membranes by slimes,
suspended solids, iron, manganese, and
precipitates of calcium carbonate and
magnesium hydroxide.
Need to stabilize finished water with pH
adjustment chemicals to prevent corrosion in
the distribution system.
Disposal of reject waste stream.
6-36
-------
Chapter 6 - Water Treatment Processes
Sanitary Deficiencies - Reverse
Osmosis
[Note: The sanitary deficiencies related to
chemical feed systems earlier in this chapter
should also be applied to this section.]
1. What performance testing is being done?
The facility should be testing for TDS, pH,
temperature, turbidity, and alkalinity.
2. What operational data is the system
collecting?
The operator needs to observe, record, and
respond to pressure pump suction, discharge
pressure, and RO unit pressure differences
between feed and product water. The difference
between feed and product water pressures over
time is a key to determining scale and
biological buildup on the membrane.
3. What chemicals are being fed and at what
dosages?
Typical scale inhibitor feed rates are 1 to 2 mg/
L. Chlorine residual should be between 1 and 2
mg/L. The facility should calculate feed rates
and dosages for the feed acid, scale inhibitor,
chlorine, and cleaning solutions.
4. Are the operators adequately protected?
Because these units require the feeding of
chlorine and various acids, operators will need
rubber gloves, eye protection, breathing
protection, rubber aprons to be worn when
mixing or pouring the acids, and a safety
shower in case of accidents or spills.
5. Are all automatic controls in operation?
RO facilities have various shut-down alarms
and automatic systems to control the facility.
Because of the high pressures and the presence
of acids, this equipment tends to fail frequently.
All automatic equipment, safety shutdowns,
and alarms must be in working order.
6. If RO-treated water is blended with
untreated water, how is the blending ratio
determined and is the final water
satisfactory?
Fluoridation
Background. Drinking water systems add fluoride
to their water in order to reduce dental cavities in
their customers. Fluoridation is a controversial
practice. The inspector's responsibility is to focus
on the sanitary risk of the fluoridation system in the
same way that he or she focuses on the sanitary
risk of any chemical feed system in a public water
supply.
Concerns. During the past few years, 2 customers
of public water systems have died as a result of a
fluoride overdose. In addition, the Centers for
Disease Control and Prevention has collected
information on 7 fluoride overfeed incidents
between 1976 and 1992. These incidents resulted in
314 reported illnesses and 2 deaths. The incident
rate over a 16-year period is less than 1 event per
1,000 systems that add fluoride. However few
these incidents, their conjunction with
considerations about operator safety make it
imperative that any fluoridation facilities be part of
the sanitary survey. This section is divided into
four parts:
General application of the fluoridation
processes.
Use of fluoride saturators (sodium fluoride).
Use of sodium silicofluoride (dry feeder
fluoride).
Use of hydrofluorosilic acid (fluoride acid
feed).
General Application
Definition. Fluoridation is the addition of fluoride
to a water supply in order to obtain an optimum
fluoride concentration in drinking water.
Chemicals. There are three chemicals used in the
application of fluoride to drinking water:
Sodium fluoride, a powder.
Hydrofluorosilicic acid, a liquid.
Sodium silicofluoride, a powder.
6-37
-------
How to Conduct a Sanitary Survey
The most common chemical used in small systems
is sodium fluoride.
Hazards. Handling fluoride chemicals, especially
powders, can have a long-term health effect on the
operator. Fluoride is a medical poison and will
accumulate in the body. Thus, it is important that
the safety hazards associated with handling this
chemical be addressed by the inspector.
Optimum Concentration. The optimum
concentration recommended by the U.S. Public
Health Service is 0.7 to 1.2 mg/L. Most states base
their optimum concentration on the ambient
temperature; they assume that as the ambient
temperature increases so does the volume of water
consumed. However, the concentration almost
always remains within the stated range. One
exception is Alaska, where the recommended range
is 1.1 to 1.7 mg/L. The lower end of the range was
selected in the belief that at least 1.0 mg/L is
required for fluoride to provide the needed
protection. The upper end of the range was selected
to remain below the secondary MCL. Other states
may have similar criteria. When a nontransient
noncommunity system (i.e., typically a rural
school) adds fluoride, it may be appropriate to feed
the chemical at a higher rate if students will be
drinking water at home that contains low
concentrations of fluoride. The inspector is
responsible for being familiar with local and
state regulations on fluoride.
fluorosis. At a concentration of 2.0 mg/L fluoride
will cause dental fluorosis.
Fluoride Saturator System
Introduction. Up-flow and down-flow saturators
are used to feed sodium fluoride. Up-flow
saturators are the most common method in small
systems. They produce a very stable fluoride
solution containing 4.0 percent sodium fluoride and
1.73 percent fluoride ion.
Equipment. Saturator systems are very simple, as
can be seen in the drawing below. The system is
made up of these basic components:
Saturator tank connected at its top to a
water supply and equipped with a manifold
at its bottom.
Float switch used to maintain the water level
in the saturator.
Water inlet system, which contains a water
meter, solenoid valve, vacuum breaker, and
a softener if the feed water is relatively hard.
Chemical feed pump.
Electrical system including fail-safe
controls.
Reaction. Fluoride in a sodium
fluoride solution is fairly stable,
so there will be little noticeable
difference between the dosage
and the residual. The notable
exception is calcium. Fluoride
will react with calcium, reducing
the fluoride residual. This is
most noticeable when the
concentration of calcium in the
exceeds 75 mg/L.
MCL. Fluoride is one of two
chemicals that has both a
primary and a secondary MCL.
(The other is copper.) The
primary MCL is 4.0 mg/L, and
the secondary MCL is 2.0 mg/L.
At concentrations above 4.0 mg/
L fluoride will cause skeletal
Fluoride Saturator
6-38
-------
Chapter 6 - Water Treatment Processes
Sodium Fluoride Considerations. Sodium
fluoride carries a UN number of 1690 and is
classified by DOT as a poison with a hazard
classification of 6.1. Fluoride dust represents a
significant health risk to the operator, so proper
PPE is critical to operator health.
Operation. Sodium fluoride is placed in the bottom
of the saturator tank, then the tank is filled with
water and allowed to stand for 2 hours. At the end
of this time the solution contains concentrations of
4.0 percent sodium fluoride and a 1.73 percent
fluoride ion. As fluoride is fed, the water level in
the saturator drops. When the water drops 3 to 4
inches, the float switch opens the solenoid valve.
The valve's opening sends water down through the
distributor and up through the fluoride crystals,
maintaining the level in the tank and preventing the
solution's concentrations from changing
significantly.
The only way to determine the amount of fluoride
fed each day is from the water meter readings on
the make-up water.
Fail-Safe. The chemical feed pump must be
connected electrically so that fluoride can be fed
only when there is a flow in the water line.
Corrosion. Sodium fluoride leaks are annoying
and the sodium fluoride is somewhat corrosive, but
not dangerous.
Dry Feeder Fluoride System
Introduction. Volumetric and gravimetric dry
feeders are used to feed sodium silicofluoride or
sodium fluoride crystals. Due to its lower cost,
however, sodium silicofluoride is most commonly
used. Dry feeder systems are usually used where
system flows exceed 1 million gallons per day.
[Note: See the chemical feed system section of
this chapter for drawings and descriptions of
volumetric and gravimetric dry chemical
feeders.]
Sodium Silicofluoride Considerations. Sodium
silicofluoride carries a UN number of 1690 and is
classified by DOT as a poison with a hazard
classification of 6.1. Because the fluoride dust
represents a significant health risk to the operator,
proper PPE is critical to protecting operator health.
Operation. Dry chemical is metered into the
solution tank based on water system flow. The feed
rate can be adjusted using a 4 to 20 mA signal
from a flow meter. The solution is either fed by
gravity to the clearwell or fed into a pressure
system by a chemical feed pump.
Fluoride Acid Feed System
Introduction. Acid feed systems are one of the
simplest fluoride feed systems used. They feed
hydrofluorosilicic acid directly from a shipping
container into the water system flow.
Equipment. An acid feed system is made up of
these basic components:
Set of scales to determine the quantity of
chemical feed.
Chemical feed pump system.
Electrical system including fail safe
controls.
Spill containment.
Fluoride Acid Feed System
nyJNT~\
6-39
-------
How to Conduct a Sanitary Survey
Hydrofluorosilicic Acid Considerations.
Hydrofluorosilicic acid carries a UN number of
1778 and is classified by DOT as corrosive, with a
hazard classification of 8. Because it represents a
significant health risk to the operator, proper PPE
is critical to operator health.
Operation. An acid feed system uses a chemical
feed pump with an anti-siphon valve to pump
concentrated acid directly into the system flow. The
only way to determine the amount of fluoride fed
each day is by weighing the solution.
Fail-Safe. The chemical feed pump must be
connected electrically so that fluoride can be fed
only when there is a flow in the water line.
Corrosion. Hydrofluorosilicic acid leaks are an
annoyance and very corrosive.
Sanitary Deficiencies - Fluoridation
1. Can the operator answer basic questions
about the fluoridation process, including
what is done, when, and why?
An operator's lack of knowledge about the
process and equipment is an indication that
failures of equipment or the effectiveness of the
process may not be resolved in a timely
manner. Management is responsible for
ensuring that operators are well trained in
the use and maintenance of fluoridation
equipment. Lack of knowledge of this key
process can be considered a significant sanitary
deficiency.
2. Is there a proper concentration of fluoride
in the distribution system at all times?
An optimum residual must be maintained for
fluoride to be effective. Generally, this residual
is 0.7 to 1.2 mg/L. Most states base the
residual on the ambient temperature of the
area. They assume that more water is
consumed as the temperature increases.
However, it is also true that water consumption
increases in areas where the winter temperature
is below freezing. Some states, such as Alaska,
set 1.1 to 1.7 mg/L as the optimum range.
Higher concentrations also may be appropriate
for rural schools.
3. Are fluoride concentrations tested in the
system daily?
A key way to prevent overfeeding of fluoride is
to test its concentration in the system. The fact
that there are primary and secondary MCLs for
fluoride also indicates that a prudent operator
would perform this test daily. In addition, any
natural fluoride in the raw water must be tested
daily because the concentration may vary from
day to day, requiring adjustments of the feed
system.
4. Does the fluoride concentration vary from
day to day?
The variation should not be more than 0.2 mg/
L. If there is a change, check to see that the
tests are conducted correctly, at the same time
of day, and under the same conditions. For
example, are pumps on or off? What is the
concentration of fluoride in the raw water?
5. Is the testing performed correctly?
There are three common procedures for testing
fluoride: the SPADNS method, the
ALIZARIN-VISUAL test, and the specific ion
probe method. Most small systems use either
the ALIZARIN-VISUAL or the SPADNS
method. These methods are prone to
interference from aluminum and
polyphosphates, respectively. The inspector
should verify that the operator knows the
proper test procedure and that the chemicals
are not past their expiration date. There are
numerous reports of false fluoride readings
based on out-of-date chemicals. The operator
should also regularly send samples to a
certified laboratory to double-check the on-site
measurements.
6. When was the testing instrument last
calibrated?
Both color tests should be performed against a
standard that is part of the routine test
procedure. The inspector should determine
whether the operator is performing this portion
of the test. If a specific ion probe is used, the
inspector should check to see how it is used
and how often it is replaced.
6-40
-------
Chapter 6 - Water Treatment Processes
7. Is there a water meter on the inlet line when
using a saturator?
The amount of fluoride solution fed each day
can be determined only by reading the water
meter on the dilution tank inlet water supply.
The inspector should determine whether this
reading is recorded each day and whether the
total amount of water used is calculated each
day.
8. How often is the saturator tank cleaned?
The fluoride saturator should be disassembled
and cleaned once a year. The crystals should be
removed and new crystals installed. This
annual cleaning and crystal replacement will
help maintain the stability of the fluoride
solution.
13. Is the electrical system wired with a fail-
safe?
When the fluoride feed system is tied to a
system pump, it is very important that some
type of flow-sensing device be used as a fail-
safe. The fluoride feed pump should not be
allowed to come on until there is a flow in the
pipe. Without a fail-safe flow detection system,
a pump motor starter may engage but not start
the pump. If the signal that engaged the pump
starter also starts the fluoride feed pump, a
highly concentrated fluoride solution can be fed
into the line and be received by a customer.
The lack of this type of system is thought to be
responsible for at least one overdose death.
9. What is the level of fluoride crystals in the
tank?
With a normal saturator using a 50-gallon
tank, the crystal level should not be allowed to
drop below 10 inches in height.
10. What method is used to dispose of old
fluoride crystals?
The proper method is mixing the fluoride
crystals with an equal amount of lime in a
metal bucket and allowing the solution to stand
for 24 hours. The reaction will generate heat,
which will result in a solid block of non-
reactive material.
11. Is there a scale for weighing the solution
tank for a liquid acid system?
The amount of acid fed each day can be
determined only by daily weighing of the
solution tank. The inspector should check to
see that this reading is recorded each day and
that the total amount of fluoride used is
calculated each day.
12. How often are the scales calibrated?
Because the dosage rate can be determined
only by weight, the scales should be calibrated
once each year.
6-41
-------
Distribution
Systems
The sanitary survey inspection must evaluate the
water distribution system to determine if it can
provide a safe, adequate, and reliable supply of
water.' Distribution system piping and
appurtenances have contributed to the deterioration
of water quality. In addition, construction and
repair techniques expose personnel and customers
to a wide variety of hazards. The inspector must
evaluate each of the operation, maintenance, and
management practices that influences the
distribution system in order to evaluate the sanitary
deficiencies. To perform this evaluation, the
inspector should be able to meet the following
objectives.
Learning Objectives
By the end of this chapter, learners should be able:
To identify data collection requirements
necessary for evaluation of sanitary
deficiencies of a water distribution system.
To review the major components of a water
distribution system including pipes, valves,
meters, meter vaults, fire hydrants, thrust
blocks, and anchors.
To describe how the type of material and
selection standards of water distribution
system components can affect system
reliability or water quality.
To identify the standards used to select
water distribution system components, and
describe how these standards protect public
health and the reliability of the distribution
system.
To identify factors that contribute to
reduction in water quality in a distribution
system.
To identify the information that should be
included on water distribution system
blueprints.
To describe the proper monitoring of a water
distribution system.
To identify operation and maintenance tasks,
such as flushing, necessary to maintain the
integrity of the water distribution system.
To describe the safety practices that should
be in place to protect the operator and
public during distribution system operation,
construction, and repair.
To describe the proper methods, based on
American Water Works Association
(AWWA) standards, for disinfecting new
and repaired water distribution system lines
and appurtenances.
To identify design and operational
constraints that have a negative effect on the
water quality in a water distribution system.
To identify design and operational
constraints that have a negative effect on the
reliability of a water distribution system.
To identify construction techniques that can
be a positive influence on distribution
system integrity.
1 The student may want to consider viewing the video Sanitary Survey Inspection; Before You Begin . . .
DISTRIBUTION prior to reading this section. To order, see www.epa.gov/safewater/dwa/orderform.pdf.
7-1
-------
How to Conduct a Sanitary Survey
Data Collection
To evaluate and assess a water distribution system
for sanitary deficiencies, the inspector should
gather the following data:
Type and quantity of piping materials.
Age and condition of piping materials.
Standards used for the construction of the
system.
Maximum and minimum pressures at high
and low elevations in the system.
Maximum and minimum pressures in each
pressure zone.
Documentation of state approval for
changes to or installation of the system.
Staffing for construction (i.e., in-house staff
or by contractors).
Number of pressure zones in the system.
Method used to separate pressure zones.
Hydraulic model of the system.
Chlorine residual testing technique used.
Method used to notify the utility when there
is a main break.
Routine maintenance tasks performed by
outside contractors.
24-hour call-out procedure.
Regulations and Standards to
Consider
The inspector should consider and review the
following information prior to an inspection:
29 CFR 1926. 650 - Competent person -
excavation safety.
29 CFR 1926. 146 - Confined space entry.
MUTCD - Manual on uniform traffic
control devices.
AWWAC-601 - Disinfection of water lines.
The AWWA standard for the type of piping
materials used in the system.
System construction standards.
State construction standards.
40 CFR 141. 73 - chlorine residual
requirements.
40 CFR 141. 86 - Lead and Copper Rule.
Distribution Systems
Basic Information
Introduction. Many failures to meet the
requirements of the drinking water standards are
directly related to poor operating and maintenance
of distribution systems or to sanitary deficiencies in
the system. Some contributing causes of poor water
quality are:
Insufficient treatment at the point of
production.
Cross-connections.
Improperly protected distribution system
storage.
Inadequate main disinfection and
unsatisfactory main construction, including
improper j oint-packing.
Close proximity of sewers to water mains.
Improperly constructed, maintained, or
located blow-off, vacuum, and air-relief
valves.
Negative pressures in the distribution
system.
Components of the Distribution
System
Introduction. A typical water distribution system
may contain the following components:
Mainlines.
7-2
-------
Chapter 7 - Distribution Systems
Service lines and service meters.
In-line valves.
Blow-offs.
Air relief, air release, and combination air
vacuum valves.
Pressure reducing valves (PRVs).
Fire hydrants.
Main Lines. Typical main line materials include:
Gray cast iron (CIP).
Ductile cast iron (DCIP).
Asbestos cement (AC).
Steel.
Polyvinyl chloride (PVC-pressure and class
pipe, also called C-900).
Wood.
High-density polyethylene (HDPE).
Gray Cast Iron Pipe (CIP)
f^p"^pw^^^^P"f^iWw^P^
jj? /
-V
Ductile Cast Iron Pipe (DCIP)
Asbestos Cement (AC) Pipe
MACHINED END I
r
ROUGH BARREL
Steel Pipe
PVC Pipe
Wood Pipe
HDPE Pipe
Services Lines. Typical service lines materials
include:
Galvanized steel
Copper
HDPE
PVC
Lead
Service Meters. There are two points where
meters are used in distribution systems:
The introduction to a pressure zone
The customer's connection
7-3
-------
How to Conduct a Sanitary Survey
Service Meter Installation
. i
LIMIT OF UTILITY INSTALLATION |
, OR PROPERTY LINE |
These meters are used to determine the amount of
water sold. They also are used to determine
unaccounted-for water and to identify leaks.
In-Line Valves. Gate and butterfly valves are the
two most common in-line valves used in a
distribution system. They are used to isolate
portions of the system during repairs.
Gate Valve
Butterfly Valve
Blow-offs. Blow-offs are gate, butterfly, or globe
valves installed at the end of dead-end lines or in
other locations. Blow-offs are used in flushing the
distribution system.
Air valves. Air relief, air release, and combination
air vacuum valves are used to remove air that
accumulates in the distribution system and to
relieve a vacuum caused by line flushing, line
breaks, or other high-flow conditions. Accumulated
air can cause system pressure and flow variations.
Vacuums can contribute to the failure of a pipe
joint and intrusion of contaminated ground water
into the system.
Air Release Valves
-a v
ft
Pressure Control. Pressure-reducing valves are
globe valves used to reduce or maintain the
pressure in a specific zone of the distribution
system.
Pressure Reducing Valve
PILOT VALVE "I
SEAT DISK I
STRAINERS 1
^CONTROL ORIFICE!
VALVE BODY
7-4
-------
Chapter 7 - Distribution Systems
Fire Hydrants. Two general
styles of fire hydrants are used in
the United States: wet barrel and
dry barrel. There are four types
of dry barrel hydrants, as shown
below: two compression types,
toggle, and slide gate. Besides
fire suppression, fire hydrants
are used to provide water for
construction, sewer line flushing,
and flushing the distribution
system piping.
Construction Considerations.
To prevent the joints of fittings
and other appurtenances from
shifting and allowing the joint to
leak, restrained joints or thrust
blocks are installed at all
changes in direction and at the
end of dead-end lines.
Wet Barrel Fire
Hydrant
Compression
Hydrants
Toggle
Hydrant
Slide
Gate
Hydrant
Opens against
flow
Opens with
flow
Sanitary Deficiencies
for Distribution
Systems
Piping Materials
1. Does the system contain
any thin-wall PVC pipe?
This material has a 2.5:1
burst ratio and will often fail
more frequently than class
C-900 pipe. In addition, this
material must be installed
with hand-tamped backfill to
prevent failure from external
loads.
2. Does the system contain
any grey cast-iron pipe?
Grey cast-iron pipe is prone
to failure from sudden
internal or external shock
loads.
3. Does the system contain
any wood pipe?
Wood pipe is easily
contaminated and, once
contaminated, is nearly
impossible to disinfect.
4. Is HDPE pipe used for
main lines or service
connections?
Petroleum products will
travel through HDPE and
other polyethylene and
polybutylene piping material
and into the water system.
This can occur if the lines
are adjacent to a leaking
underground fuel storage
tank or if fuel is spilled on
the ground above the line.
7-5
-------
How to Conduct a Sanitary Survey
5. Does the system contain any steel pipe
that is more than 35 years old?
In most locations, steel pipe is given a design
life of 35 years. If the ground is wet or the soil
is aggressive, the pipe may deteriorate in less
time. Leaks in steel pipe are normally in the
form of pin holes. If there is a high velocity
through the pipe, then contaminated ground
water may be drawn in through these same pin
holes.
6. Does the system contain any solvent-weld
PVC pipe larger than 2 inches in diameter?
Large-diameter solvent-weld PVC pipe has a
higher failure rate than push-on joint pipe. This
is due to the expansion and contraction of the
pipe caused by temperature changes during
construction or operation.
7. Are there any lead goosenecks still in
place and being used for service
connections? If yes, how many? Are there
plans to remove these? If yes, by what
date?
Lead goose necks have been identified as one
of the major contributors to high lead levels in
finished water.
Material Standard
1. What standards are used to select
materials?
The distribution system components should be
selected to meet current standards including
NSF 61 for indirect additives. The corrosive
effects of finished water on metal pipe used for
service lines are considered, together with
possible toxicological effects on consumers,
resulting from dissolution of the metals. Only
NSF-approved plastic pipe should be used,
when plastic pipe is acceptable. Caulking
materials should not support pathogenic
bacteria and should be free of tar or greasy
substances. Joint-packing materials should
meet the latest AWWA specifications.
2. Are all materials used in the system
manufactured according to AWWA
standards?
The AWWA standard is a "buyer beware"
standard. It is the purchaser's responsibility to
require the manufacturer or supplier to provide
proof that the material meets these standards.
AWWA does not test material, and it does not
have standards on all construction materials or
all sizes of mains.
3. Are all materials ANSI/NSF certified?
See qualification in question 1.
4. Is there a set of construction standards
used by the utility?
Failure to use construction standards often
complicates the installation of piping, valves,
and hydrants that are of different brands, types,
and materials. This contributes to increased
materials inventory costs and maintenance
worker training. For a small utility, this
increased cost may mean that all appropriate
training and repair materials will not be on
hand. In addition, lack of construction
standards may contribute to poor quality
construction, which results in premature failure
of materials.
5. Does the system have its own
construction standards, or has it adopted
some from another agency?
Many small utilities borrow construction
standards from a larger local community.
While this can work, the standards often do not
fit the needs of the community. This can cause
contractors and staff to ignore the standards.
The result is the same as not having a standard.
6. Do the construction standards meet state
requirements?
Because some states do not review construction
standards, the utility may have adopted
standards that violate existing state standards.
Assuming the state standards were developed
to provide the minimum degree of reliability to
the system, the utility's standards should be
consistent with, and at least as protective as,
the state requirements.
7-6
-------
Chapter 7 - Distribution Systems
7. Are in-house staff and contractors
required to use the same standards?
In many locations, staff construction methods
may vary from those used by contractors. The
lack of consistency in construction methods
and in the standardization of materials leads to
maintenance problems and slows repairs during
emergencies.
8. Are standards actually followed?
Take a look at the set of standards and
compare them to blueprints and materials in
storage. If the system is not following its own
standards, the actual construction techniques
are suspect. Thus, the system may not be
reliable.
Water Quality
1. Is there any point in the system where
pressure drops below 20 psi during peak
demand or fire response?
Pressures below 20 psi are considered to
represent a sanitary deficiency. At pressures
this low, or even negative, it is possible for
contaminated ground water to enter through
leaks. Also, a backflow condition could occur
due to backpressure. The system must be
designed to supply adequate quantities of water
under ample pressure and operated to prevent,
as far as possible, conditions leading to the
occurrence of negative pressure. Steps to
prevent negative pressure include minimizing
unplanned shutdowns, providing adequate
supply capacity, correcting undersized
conditions, and properly selecting and locating
booster pumps to prevent the occurrence of a
negative head in piping subject to suction.
Continuity of service and maintenance of
adequate pressure throughout a public water
supply system are essential to prevent
backsiphonage. The inspector should determine
if complaints about inadequate pressure have
been registered and if there is a program to
periodically monitor pressures throughout the
system.
2. If the valves are in a vault, can the
operator observe pressures without
entering the vault? If the valves are in a
confined space, does the operator have
and use gas monitoring equipment and
follow a confined space entry procedure?
Vaults are typically confined spaces. Do not
enter. If the operator must enter the space and
does not use a proper confined space entry
procedure, this is a sanitary deficiency. Injury
or illness that keeps the operator from
performing required duties reduces the
system's reliability.
3. If there is a vault, is there a sign
identifying it as a confined space?
All confined spaces must be labeled with a red,
white, and black injury-prevention tag.
4. If there are pressure zones controlled by
automatic pressure reducing valves
(PRVs), do the PRVs work properly?
Check upstream and downstream pressures.
(The absence of pressure gauges above and
below the PRV is considered a sanitary
deficiency because the operator is unable to
determine if the PRV is working properly.) If
the upstream and downstream pressures are the
same, have the operator open a fire hydrant
downstream and observe the reaction of the
pressure across the valve.
5. If there are PRVs, can the operator
describe how they work and what they do?
The operator's lack of knowledge about key
components of the system is a sanitary
deficiency. Such a lack makes it unlikely that
any problems which arise will be solved in a
timely manner. Failure of a PRV can cause
high downstream pressures that can lead to the
failure of main lines and services.
6. How would the utility be notified if a PRV
fails?
The failure of the PRV to reduce pressure can
cause a main or service line to break. Low
pressures can result in backflow from
backpressure or backsiphonage. The longer a
failure goes undetected, and the longer the
delay in fixing it, the greater the possibility of
contaminating the system.
7-7
-------
How to Conduct a Sanitary Survey
7. Is the system designed with dead-end
lines?
Areas of stagnant water in a distribution
system may result in bacteriological regrowth,
red water, or customer complaints. These areas
should be flushed routinely, and long-range
plans for connection should be put into place if
they are feasible. Records should be kept of
complaints and corrective actions taken.
8. Are there several low places in the piping
system?
Low areas in the piping system can accumulate
silt and organic material that can reduce
chlorine residual, grow bacteria, and cause
odor and taste problems. Question 7, above,
explains for how to correct the problem.
9. Do reservoirs turn over at least once every
14 days?
Water held in a reservoir for more than 14 days
can become stagnant, causing taste and odor
complaints, a reduction in chlorine residuals,
and an increase in bacteriological activity.
10. If there is a hydraulic model, has it been
compared to actual conditions? When was
it last updated? Does it show any low-
pressure conditions?
Hydraulic models help the manager identify
low-pressure points and areas of inadequate
supply. While the lack of a hydraulic model is
not considered a sanitary deficiency, it can be if
there are low-pressure problems that have not
been addressed by use of a model or other
specific method. A model that has not been
calibrated against actual system data is of little
value.
11. Are backflow prevention devices installed
and tested at each commercial site where
backflow could cause a reduction in water
quality?
This issue is discussed in depth in the cross-
connection chapter. These devices are
necessary to prevent contamination of the
system.
12. Does the discharge piping on all air valves
extend a proper distance above ground
and flood level?
One source of contamination is surface water
that enters the distribution system through air
valves.
13. Are distribution system problem areas
identified on a system map?
A map or other record keeping system for
system problems is a good indicator of
management support for solving system
problems. If the utility is not using a map or
other system to record system problems, are
they aware of their problems? Lack of
awareness means that the problems will not be
resolved in a timely manner.
Maps, Drawings and Planning
1. Are as-built drawings available?
As-built drawings are scaled drawings that
show the actual locations of all constructed
facilities. The lack of as-built drawings makes
it difficult for the staff to perform proper
repairs in a timely manner.
2. How often are maps updated?
Drawings and as-builts that are not updated at
least once each year do not reflect current
conditions. Inaccurate data can cause the staff
to obtain the wrong materials and thus delay a
repair. If this happens too many times, the staff
may stop using the drawings.
3. Do maps and as-builts contain the proper
information?
Maps and as-builts should contain the
following information, or the information must
be available in some form of asset data base:
pipe size, date of installation, pipe material,
line valve and blow-off locations, hydrant
locations, storage tank locations, and
interconnections to other systems.
7-8
-------
Chapter 7 - Distribution Systems
4. Is there a master plan showing proposed
construction and replacement lines?
To provide adequate and reliable service now
and in the future, system changes and additions
should be based on a master plan. If this plan
does not exist, the utility commonly responds
to developers' needs. This can cause the system
to expand lines to areas that cannot be served
with adequate pressure.
Distribution System Monitoring
1. Are chlorine residuals tested in the system
as required?
The Surface Water Treatment Rule (SWTR)
requires residuals to be measured at the same
time and place as coliform samples are
collected. Many states require daily monitoring
of disinfectant residuals in the distribution
system. The maintenance of a chlorine residual
is the last line of defense against waterborne
disease. This is one of the key quality control
items in the operation of a water system.
2. Is the residual at least 0.2 mg/L prior to the
first customer?
This is a SWTR requirement. It assumes that
this residual is available after contact time
(CT) requirements have been met.
3. Is a trace of residual maintained at
coliform sampling points?
This is a SWTR requirement. It is good
operational practice to keep a measurable
residual at all points in the distribution system.
If any point in the system does not have a
chlorine residual, the water quality is suspect.
4. Are there an adequate number of residual
sampling sites, and do they provide a
representative sample of system
conditions?
Sampling points should be established so the
utility can monitor disinfectant residuals in the
entire system. Small systems may be able to
rotate through a number of sample sites to get
an overall picture of disinfectant residuals.
5. Is the correct reagent used for testing free
residual?
Check the reagents. Many times operators
accidentally use reagents for total chlorine
residual when using free chlorine as a
secondary disinfectant.
6. Are operators waiting the correct length of
time before reading the residual?
Some kits require the test for DPD to be
completed within 1 minute of adding the
reagent for free chlorine and within 3 to 5
minutes for total chlorine. In general, the
manufacturer's instructions should be followed
when using field test kits.
7. When was the testing instrument last
calibrated?
Color wheels have a life of about 1 year. In
addition, spectrophotometers can give false
data. The spectrophotometer should be checked
against a color wheel once a quarter, or when
the operator suspects the accuracy of the data.
8. Is system pressure monitored at high and
low elevations? Is this information
recorded?
To obtain representative data, system pressure
must be measured at high and low elevations.
In addition, data should be recorded using blue
ink. See Water Quality question 1, above, for
more information on low-pressure problems.
9. Are customers' water quality complaints
recorded?
Many states require utilities to record the
nature and response to all water quality
complaints. With the 1996 Amendments to the
Safe Drinking Water Act requiring that
customers be given water quality information
in the Consumer Confidence Report, this is no
longer just good operations and customer
relations. By recording and analyzing customer
complaints, a manager can prevent problems,
or address them before they get out of hand.
Many customers are very sensitive to changes
in water quality, and a positive response to
customer problems is a good management
practice.
7-9
-------
How to Conduct a Sanitary Survey
10. What is the percentage of unaccounted-for
water?
A high quantity of unaccounted-for water,
above 15 percent, is an indication of either
inaccurate meters or excessive leakage.
Inaccurate meters result in a utility not being
paid for all the water that is consumed,
reducing income and making it more difficult
to maintain the system. Holes in pipelines and
bad pipe joints are potential entry points for
contaminated ground water.
System Operation and Maintenance
1. What is the frequency of main breaks?
The best number is zero, however, main breaks
are one of the normal problems in a water
system. If the breaks are frequent, there may be
a problem with the integrity of the piping
material. (Frequency depends on area and type
of piping material.) Each main break opens the
system to contamination, and frequent breaks
increase the potential for introducing
waterborne pathogens into the system.
Most breaks are due to leaks, not age. The
leaks undermine the pipe, causing it to fail
under the weight of the overburden. To prevent
main breaks, a routine leak detection program
should be conducted and a record of
distribution system repairs should be kept. This
record should identify the location and type of
repair, repair device or length of replacement
pipe, and general condition of the line.
2. Are the breaks primarily in one area? What
type of pipe is involved?
If management has this type of information, it
is an indication that they are attempting to
address problems before they become critical.
This information should be compared with the
master plan to ensure that they are in
agreement. The lack of this information may be
considered a lack of response by management
to the system's deteriorating conditions.
3. Is there a line flushing program? Is a
systematic unidirectional process used?
Are records maintained of frequency,
location, and amount of time required?
The whole system should be flushed once or
twice a year to clear sediment in the lines. The
flushing should be well planned and carried
out, preferably beginning at points near the
water plant and storage facility and moving to
the outer ends of the system. A minimum
velocity of 2.5 fps must be maintained during
the flushing. This can be done only cutting off
portions of the distribution system with
isolation valves so the direction of the water
flow is known and comes from a single line. A
pitometer should be used to measure flow at
questionable areas of the distribution system
when the flushing begins.
4. Is there a valve inspection and exercising
program and are records maintained?
Every valve in a system should be inspected
and exercised annually. This should include
completely closing, opening, and re-closing
until the valve seats properly. Leaking or
damaged valves should be scheduled for repair.
A record of valve maintenance and operation,
including the number and direction of turns to
closure, should be kept.
5. Is there a fire hydrant flushing program
separate from the line flushing program?
Fire hydrant leads can be a source of water
quality deterioration. The water can become
stagnant, consuming chlorine, causing odor
and taste problems, and increasing
bacteriological counts. Annual flushing can
prevent this problem.
6. Does the utility have a backhoe? If not,
how long would it take a contractor or
rental company to provide one if needed?
Can this equipment be obtained late at
night?
The lack of equipment such as a backhoe can
prevent the staff from making repairs in a
timely manner. The longer a portion of the
system is shut down at a reduced pressure, the
greater the opportunity for contamination.
7-10
-------
Chapter 7 - Distribution Systems
7. How often are pressure readings taken in
the distribution system? Are they
representative of the system?
A program to read pressures may be conducted
in conjunction with the fire department to
determine adequacy of fire flow. A record of
pressures and flows throughout the system may
help to identify problems. If the programs are
conducted during the day and at night, they
will indicate hydraulic efficiency under
common requirements.
8. Are adequate repair materials on hand?
If repair materials are not available, how many
hours would it take to obtain these materials at
2:00 a.m? The minimum materials include two
full-circle repair bands for each pipe size, two
cast-iron couplings for each pipe size, two
cast-iron pipe joint repair bands, and one
length of each size of pipe.
9. Are there written procedures for isolating
portions of the system and repairing
mains?
Written emergency response procedures
improve the water system's reliability. In a
small system, they provide a way to handle
unexpected problems when the regular operator
is not available. They also give the operator a
means of dealing more effectively with non-
routine tasks.
10. Does the utility maintain an updated list of
critical customers?
Reducing water pressure, shutting off service,
or reducing water quality can severely affect
some customers, including hospitals, clinics,
photo developers, and users of special medical
equipment. It is important for customer support
and for the reduction of liability to maintain a
list of these customers and to notify them of
changes in the system that could adversely
affect them.
11. Does the utility have a corrosion control
program?
The utility should have a program to evaluate
corrosion and the effectiveness of a program
to control contaminants such as lead and to
minimize red water complaints. A record of
complaints and the corrective actions should be
kept.
Safety Considerations
1. Does the utility use proper safety
procedures for handling line disinfection
chemicals?
This is an Occupational Safety and Health
Administration (OSHA) requirement. It
includes using proper personal protection
equipment (chlorine and dust filter respirator
for calcium hypochlorite, gloves and chemical
goggles for sodium hypochlorite). There must
be a written procedure for transporting and
handling chlorine. This procedure should be
referenced in the hazard communication
program list of non-routine tasks.
2. Is there a trained, competent person on
the staff?
This is an OSHA requirement.
3. Does the competent person evaluate soil
and work site hazards at each excavation?
This is an OSHA requirement.
4. Are excavation hazard evaluations
documented?
This is an OSHA requirement.
5. Does the utility have and use cave-in
protection equipment?
Cave-in protection equipment must be used in
any trench more than 5 feet deep (4 feet deep in
some states). The competent person must know
how to select the correct protection system
based on soil testing results.
7-11
-------
How to Conduct a Sanitary Survey
6. Does the utility have and does it use proper
traffic control equipment?
According to the MUTCD, all temporary signs
must be orange and black and at least 36
inches X 36 inches. Stop and go paddles must
be at least 18 inches. Cones must be at least 18
inches tall, and each work site must have at
least 13.
7. Have all field workers been trained in the
use of traffic control equipment?
Failure to provide training is one of the most
common safety violations.
8. Do all employees who operate industrial
trucks have a Commercial Drivers
License?
This is a U.S. Department of Transportation
requirement.
Disinfection Procedures
1. What disinfection procedure is used for
new lines?
The procedure outlined in the AWWA Standard
for Disinfecting Water Mains (C651 -99)
should be followed (25 mg/L of chlorine not to
drop below 10 mg/L after 24 hours). The
inspector should ask the operator what
procedures are used. The final determining
factor should be that new mains should
demonstrate negative bacteriological results
prior to being placed into service.
2. Does this procedure meet the AWWA C-651
Standard?
Three methods are described in C-651; the
least reliable is the use of chlorine tablets.
3. What disinfection procedure is used
during repairs of broken lines?
It is common industry practice to disinfect all
repair parts and any contaminated line with
sodium hypochlorite. (If proper disinfection
practices have been followed, in most cases
repaired mains may be returned to service prior
to determining the bacteriological quality of the
water because the sanitary risks of loss of
service and cross connections are likely
greater than that of bacterial contamination.)
Design and Operational Constraints on
Water Quality
1. Are water lines looped, or are there dead
ends?
Dead-end lines can lead to reductions in water
quality. Where a pipe is dead ended for future
expansion, it is desirable to provide some type
of temporary loop or to flush the line
frequently.
2. Are there any bottlenecks in the piping
system (a small diameter pipe connected
on both ends by large diameter pipe)?
Bottlenecks cause high velocities, which can
cause a Venturi effect, drawing contaminated
water into the system through leaks in the
bottleneck.
3. Are blow-offs connected to sanitary or
storm sewers, or do they exit below flood
level in ditches or streams?
Blow-off connections to sewers or sewer
manholes are a direct cross-connection and are
prohibited.
Design and Operational Constraints on
Reliability
1. Is the system interconnected with any
other water systems?
An interconnection to a second water system
may provide an alternative source in the case
of drought, contamination of the primary
source, or similar emergency.
2. Does the system have adequate valves?
The system should have enough isolation and
blow-off valves to make necessary repairs
without undue interruption of service over any
appreciable area.
7-12
-------
Chapter 7 - Distribution Systems
Construction Considerations
1. Are concrete thrust blocks or restraining
fittings used at all elbows, tees, and dead
ends?
Concrete thrust blocks must be used to restrain
all fittings, elbows, tees, and dead ends.
2. Are proper bedding and backfill
procedures used with new or repaired
pipes?
Bedding and backfill protect pipes from
external damage. With PVC, they also support
pipe walls and protect them from deflecting
and thus breaking longitudinally.
3. Are pressure or leak tests performed on all
new pipe construction?
Pressure tests check the integrity of the piping
material. Leak tests check the integrity of the
pipe joints.
4. Are cast-iron and steel pipe protected from
external corrosion?
Placing poly bags over cast-iron pipe is the
best way to protect it from external corrosion
and thus extend its life. Steel pipe is protected
with any one of many external coatings.
7-13
-------
Cross-Connections
Cross-connections in water systems are a
significant sanitary risk that threaten drinking
water quality and public health.1 During a sanitary
survey, the inspector must first evaluate the
adequacy of the system's cross-connection control
program. Second, the inspector should identify
cross-connections that are owned or controlled by
the water system in the treatment facility and in the
distribution system. To perform these evaluations,
the inspector should be able to meet the following
objectives.
Learning Objectives
By the end of this chapter, learners should be able:
To define the term cross-connection and
recognize common cross-connections.
To differentiate between the two types of
backflow that can occur due to cross-
connections: backpressure and
backsiphonage.
To determine if adequate pressure is
maintained in the distribution system.
To identify devices to prevent
contamination, explain their operation, and
determine if they are installed properly.
To evaluate the water system's cross-
connection control program and its
implementation.
To identify unprotected cross-connections
within the water system, including those in a
treatment facility, pumping station, or
distribution system.
To determine if the appropriate backflow
prevention devices are used, properly tested,
and maintained depending on the degree of
hazard.
Data Collection
To evaluate the system's compliance status, the
inspector should review the following information:
System's written cross-connection control
program.
Number and type of backflow preventers in
the system.
Frequency of testing of backflow preventers.
Qualifications of persons authorized to test
devices.
Number of plans for new building
construction that are reviewed.
Regulations and Standards to
Consider
The inspector should consider or review the
following information prior to the inspection:
State regulatory requirements for cross-
connections.
1 The student may want to consider viewing the video Sanitary Survey Inspection; Before You Begin . . .
CROSS-CONNECTIONS prior to reading this section. To order, see www.epa.gov/safewater/dwa/
orderform.pdf.
8-1
-------
How to Conduct a Sanitary Survey
EPA's Cross-Connection Control Manual.
AWWA's Manual of Cross-Connection
Control, M-14.
'Manual of Cross-Connection Control,
Foundation for Cross-Connection Control,
University of Southern California.
Cross-Connections
Basic Information
Cross-Connection Defined. To prevent
contamination of its water, a system must make
sure that service connections are properly made
and continually monitored for cross-connection
hazards. A cross-connection is an actual or
potential physical connection or arrangement
between otherwise separate potable water piping
systems and any contaminant that allows water
to flow between the two systems. Hazards occur
when a contaminant flows toward the potable
supply. Unless controlled, cross-connections can
result in contaminated water replacing potable
water at various sites within a water system. There
is a potential for the contamination to spread
throughout the distribution system, endangering the
health of the entire community.
Plumbing Defects. Plumbing defects can occur in
any part of a water system, and cross-connection
hazards can occur where outside water pressure
can exceed potable water pressure. Cross-
connections must be prevented or controlled at all
service sites. The water treatment plant is often the
site of a number of cross-connections.
Types of Cross-Connections. A cross-connection
link can be made either as a pipe-to-pipe
connection, in which potable and contaminated
water pipes are linked without proper control
valves, or as a pipe-to-water connection, in which
the outlet from a potable water supply is
submerged in contaminated water. Cross-
connections are usually made unintentionally or
because their hazards are not recognized or are
underestimated,
Backpressure and Backsiphonage. The two major
types of cross-connection hazards, backpressure
backflow and backsiphonage backflow, are
distinguished by their origins. Backpressure
backflow refers to the flow of contaminated water
toward a potable supply when the contaminated
water's pressure is greater than the potable water's
pressure. Backsiphonage backflow results from
negative pressure (a vacuum) in the distribution
pipes of a potable water supply. Contaminated
water is sucked up toward the potable supply.
Control of Cross-Connections. Successful control
of cross-connection hazards depends not only on
inspecting for cross-connections by a water system
and by water users, but also on an enforceable
cross-connection control program. If a community
subscribes to a modern plumbing code, such as the
National Plumbing Code, its provisions will govern
backflow and cross-connections. However, the
water system must obtain authority to conduct a
community inspection program through an
ordinance or other means and carry out a
comprehensive program.
Components of Water System's Cross-
Connection Control Program
A cross-connection control program should have
these basic components:
Ordinance or other authority to establish a
program.
Technical provisions to eliminate cross-
connections.
Right of entry and inspection of existing
facilities served by the system.
Backflow prevention device testing, repair
and recordkeeping.
Certification of backflow prevention device
testing personnel.
Review of new construction plans to ensure
no cross-connections are present.
Penalty provisions for violations.
Protection Against Sanitary
Deficiencies from Cross-Connections
Cross-connections at sites serviced by a water
system can usually be controlled at the sites
themselves. For example, a submerged water outlet
in an apartment building could result in
8-2
-------
Chapter 8 - Cross Connections
Backflow as a Result of Backpressure
BOILER
Backflow as a Result of Backsiphonage
CROSS
I CONNECTION
CHEMICAL
FEED
(eg SCALE
INHIBITOR)
8-3
-------
How to Conduct a Sanitary Survey
Backflow as a Result
of Hydraulic Head
Backflow as a Result of Backsiphonage
t
cc
LU
WELL
Direct Cross Connection
SAFETY
SHOWER
WATER
MIXING TANK
J
Indirect Cross
Connection
ACID
8-4
-------
Chapter 8 - Cross Connections
Air Gap
Diameter-I-
"2L
7
contamination of the water for the entire building
(as well as threaten the water facility's supply) if
the pressure of the contaminated water exceeds that
of the potable water.
Pressure. An important aspect of reducing the
threat from cross-connections is maintaining
adequate pressure in the distribution system. States
usually have a minimum pressure requirement of at
least 20 psi under all conditions of flow in all
portions of the system.
Devices. A number of devices are available to
prevent cross-connections, including the following:
Air Gap. To prevent a cross-connection
hazard in the apartment example above,
each fixture in the
building should have a
vertical air gap of twice
the diameter of the pipe or
fixture between its water
outlet and its flow level
rim. This will eliminate
the physical cross-
connection link and
protect the building (and
the municipal supply)
against backflow. An air gap may also be
made where the water service enters the
building. This protects only the municipal
supply, however, and not the building
system.
Example: The faucet is at least two times
the diameter above the highest level in a sink
or tub.
Other Devices. Other backflow prevention
devices can be installed when an air gap
cannot be made. They also provide backup
when air gaps are made. Surge tanks in
booster systems, color-coding, and labeling
of pipes in dual water systems also help
protect buildings against cross-connection
backflow.
Although state requirements may vary, it is
generally agreed that backsiphonage can be
prevented by installing vacuum breakers at
water outlets where contaminated water is
present (for example, at toilets and urinals
equipped with flushometers, or at makeup
water for a chemical solution tank). Vacuum
breakers can also be used at hose bibs and
in connection with in-ground lawn irrigation
systems. They are not, however, effective
against back pressure.
Atmospheric Vacuum Breaker. An
atmospheric vacuum breaker is activated by
atmospheric pressure to block the water
supply line when negative pressure develops
in the line. This action admits air to the line
and prevents backsiphonage. A vacuum
breaker will not provide protection against
backflow resulting from backpressure and
should not be installed where backpressure
may occur. Vacuum breakers must be
installed a minimum of 6 inches above the
highest outlet. Vacuum breakers are not
suitable for continuous use because they
may stick open. Therefore, they cannot have
a valve on the downstream side, like a spray
nozzle on a hose, that can shut water off.
Atmospheric Vacuum Breaker
Flow Condition
Non Flow Conditions
Pressure Vacuum Breaker (PVB). The
PVB device is installed in pressurized
systems and operates only when a vacuum
occurs. It is usually spring loaded and
should be specially designed to perform
adequately after extended periods under
pressure. This device is suitable for use
when a high degree of hazard is present but
only under backsiphonage conditions, for
example, on irrigation systems. Pressure
vacuum breakers must be installed a
minimum of 12 inches above the highest
outlet. They must be tested at least annually.
Double-Check Valve Assembly. The
double-check valve assembly is a reliable
8-5
-------
How to Conduct a Sanitary Survey
Pressure Vacuum Breaker (PVB)
| NORMAL FLOW
means of backflow protection from non-
health hazards. For example, it can be used
to protect the water supply against
contaminants that would cause only
aesthetic changes to water quality. As in the
case of other backflow preventers, the
double-check valve assembly should be
inspected and tested annually. Homemade
double check valve assemblies are not
suitable because they cannot be tested for
proper operation.
Reduced Pressure Zone Backflow
Preventer (RPZ). The RPZ device is the
most reliable of the mechanical devices used
to prevent backflow and can be used for
both backpressure and backsiphonage. It
should only be used for non-health or health
hazards. RPZs are often used to provide
protection on make-up water to boilers. This
device consists of two independently loaded
pressure-reducing check valves and a
pressure-regulated relief valve located
between them.
Because all valves may leak as a result of
wear or obstruction, the protection provided
by the check valves is not considered
sufficient. If some obstruction prevents a
check valve from closing tightly, the leakage
back into the central chamber would
increase the pressure in this zone, the relief
valve would open, and flow would be
discharged to the atmosphere.
Double-Check Valve Assembly
Reduced Pressure Zone Backflow
Preventer (PRZ)
The double-check system has the advantage
of a low head loss (maximum 10 nsi). With
the shut-off valves wide open, the two
checks, when in an open position, offer little
resistance to flow.
Malfunctioning of one or both of the check
valves or the relief valve is indicated by a
continuous discharge of water from the
relief port; small amounts of water may be
periodically discharged during normal
operation. Under no circumstances should
plugging of the relief port be allowed,
because the device depends on an open port
for safe operation.
8-6
-------
Chapter 8 - Cross Connections
Device Use and
Maintenance
Testing Required. All types of
backflow preventers should be
tested at least annually to assure
their proper function.
Certified Testers. Many states
now require the certification of
individuals who test backflow
preventers. This is an important
component of a system's cross-
connection control program.
Water systems may have their
own employees certified, or
allow private contractors to test
devices.
Chlorine Split Feed
Cross-Connections
Owned or Controlled by the Water
System
Requirements. In addition to the many cross-
connections that may exist on the premises of a
water system's customers, there can also be cross-
connections that are owned or controlled by the
system itself. These potential cross-connections
should be subject to the same scrutiny as those that
are privately owned.
Location of Cross-Connections. There can be
cross-connections in water treatment plants,
pumping stations, or in the distribution system that
can pose a risk to water quality and public health.
During a sanitary survey, the inspector should
identify all cross-connections that are under the
water system's control.
Water Treatment Plants. Water treatment plants
can have a variety of potential cross-connections.
The inspector should determine whether the
following cross-connections exist. If they do exist,
the water system should eliminate them with an air
gap or, if that is not possible, the appropriate
backflow-prevention device.
Submerged inlets or water piped directly to
chemical feed tanks.
No antisiphon valves on chemical feeders.
Hose bibs without vacuum breakers.
Laboratory aspirators.
Split chemical feeds to raw or partially
treated water and finished water. Examples
are pre- and post-chlorination or pre- and
post-caustic addition for pH control.
Surface wash on filters.
Filter-to-waste piped directly to a drain.
Drain or sewer traps with direct water
injection.
Surface Wash Filter
8-7
-------
How to Conduct a Sanitary Survey
Floor drains that allow water to be returned
to the process stream.
Lack of legends and color coding on pipes.
Bypasses around backflow preventers.
Feed water to boilers with chemical
injection.
Water loading stations for bulk water sales.
Pumping Stations. Pumping stations should also
be inspected for cross-connections. Potential cross-
connections include:
Priming of raw water pumps with finished
water.
Air relief valves piped directly to a drain.
Cooling water for an emergency generator
submerged in a drain or returned to the
potable supply.
Air Relief Valve Incorrectly Piped
Directly to Floor Drain
AIR VACUUM RELEASE
OR DRAIN I
Distribution System. Many of the potential cross-
connections in a distribution system cannot be seen.
Therefore, the person responsible for the operation
of the distribution system must be relied on to
provide the appropriate answers relating to these
cross-connections:
Submerged blowoff in streams.
Water mains passing through sewers.
Connections to unapproved water systems or
sources (i.e., fire systems or private wells).
Submerged inlets in the water system's own
meter testing equipment.
Air relief valves in pits where their open
ends may be submerged.
Submerged relief ports from pressure-
reducing valves.
Overflows from storage tanks piped directly
to storm drains or sewers.
Direct connections to sewers for flushing
either the water main or sewer.
Hydrants with drain lines to sewers.
Uncontrolled use of fire hydrants.
(Contractors and others who use fire
hydrants should only be allowed to do so
when the flow is metered and the
distribution system is protected against
backflow with an RPZ.)
Filling newly installed mains from fire
hydrants for flushing and disinfection.
Hydrant Drain to Manhole
8-8
-------
Chapter 8 - Cross Connections
Sanitary Deficiencies and Cross-
Connections
During a sanitary survey, the inspector should
undertake two major activities related to cross-
connections. The first is to evaluate the adequacy
of the water system's cross-connection control
program. The second is to look for cross-
connections that may be owned or controlled by the
water system. (These cross-connections may be in
the water treatment plant, at pumping stations, or
in the distribution system.) To perform these major
activities, the inspector should determine the
answers to a number of questions.
1. Does the water system have a written
cross-connection control program?
The inspector should determine if the system
has a formal written program for controlling
cross-connections. The program should be
reviewed to determine if it has the following
basic components:
Authority to establish a program.
Technical provisions.
Right of entry and inspections.
Device testing and repair.
Certified testers.
Plan review and inspection of new
construction.
Penalties.
2. Is the program active and effective in
controlling cross-connections?
To determine if the program is being
implemented effectively, the inspector can
review its staffing and the records of the
number of inspections that are conducted, the
number of various devices installed in the
system, and the number of tests that are
performed.
3. Are there cross-connections at the water
treatment plant?
During a sanitary survey of a water treatment
plant, the inspector should look for cross-
connections. The likely locations of cross-
connections are submerged inlets in chemical
feed tanks, connections between potable water
lines and process water, split chemical feeds in
chlorination systems that pre- and post-
Example of Cross Connection Downstream of Air Vacuum Breaker
Incorrect Cross-connection Control
for Seal Water - Valve down
stream of air vaccum breaker
8-9
-------
How to Conduct a Sanitary Survey
chlorinate, surface wash, and filter-to-waste
connections to sewers. Also during the sanitary
survey, the inspector should discuss with the
plant operator the importance of eliminating
cross-connections.
4. Does the system test backflow preventers
at treatment plants and other facilities it
owns?
The inspector should determine whether
devices are tested at least yearly. Even a
system that does not have an active cross-
connection program needs to ensure the
continued proper operation of its backflow
preventers. Color coding and legends on piping
also are useful in minimizing cross-connections
and should be evaluated during the inspection.
5. Are there cross-connections in pumping
stations?
While inspecting pumps and pumping stations,
the inspector should identify any potential
cross-connections. They can include raw water
pumps that are primed with finished water, air
relief valves piped directly to a drain, cooling
water for emergency generators with
submerged outlets, and cooling water that is
returned to the potable system.
6. Are there cross-connections in the
distribution system that the water system
owns or controls?
To evaluate the presence of cross-connections
in the distribution system, the inspector must
speak with the person responsible for
distribution system operations. In small
systems, the entire system may be operated by
one person. In larger systems, responsibility for
treatment plant operation and distribution may
be split. The inspector should question the
operator carefully about distribution cross-
connections. Examples of these are submerged
blow-offs, direct connections to sewers, water
mains in sewers, connections to unapproved
systems, hydrant drain lines to sewers, and
overflow from storage tanks pined directly to
sewers or drains.
7. Does the water system have a program to
control the use of fire hydrants?
The use of fire hydrants by non-water system
personnel for filling tanks, cleaning sewers, or
providing water for construction projects has
the potential to create serious cross-connection
hazards. The inspector should determine if the
water system has a program to ensure that fire
hydrants are not used for these purposes or, if
they are used, that appropriate procedures are
followed to prevent backflow. These
procedures can include a permit system that
requires the use of air gaps and backflow
preventers.
8-10
-------
Monitoring and
Laboratory Testing
An important activity for water systems,
monitoring is required to determine compliance,
e.g., the presence of chlorine residuals, and to
determine the effectiveness of the treatment
process.1
Learning Objectives
By the end of this chapter, learners should be able
to evaluate quality assurance in monitoring and
laboratory testing. Specifically, they should be
able:
To identify responsibilities and requirements
of water purveyors with respect to
monitoring.
To determine if in-house testing facilities,
procedures, and equipment are adequate.
To determine if test equipment is calibrated
and maintained properly.
To determine if reagents have an unexpired
shelf life and are discarded appropriately
after expiration date.
To determine if the operator is performing
tests properly.
To determine if treatment adjustments are
made based on laboratory results.
To determine if certified laboratories are
used when required.
Data Collection
To evaluate the system's compliance status, the
inspector should review the following information:
Any violations of MCLs, treatment
techniques, monitoring, or reporting.
Current information on population served
and number of services.
State-approved coliform sample siting plan.
State-approved locations for THM samples.
Variances or exemptions that apply to the
system.
Compliance with orders that apply to the
system.
Documentation of State approval for the
installation of, or changes to, the system.
Regulations and Standards to
Consider
The inspector should review the following
information prior to the inspection:
EPA or state primary and secondary
drinking water regulations.
State design standards or guidelines.
ANSI/NSF standards.
1 The student may want to consider viewing the video Sanitary Survey Inspection; Before You Begin .. .
SAMPLING AND MONITORING prior to reading this section. To order, see www.epa.gov/safewater/dwa/
orderform.pdf.
9-1
-------
How to Conduct a Sanitary Survey
Monitoring and Laboratory Testing
Basic Information
Approved Laboratory. Monitoring requirements
related to specific provisions of the Safe Drinking
Water Act (SDWA) regulations are dealt with in
Chapter 2, Regulations. Much of the required
monitoring, with the exception of monitoring for
turbidity and chlorine residual, must be performed
by a certified laboratory, either the system's own
laboratory or a contract laboratory.
In-House Monitoring. The operator must establish
adequate in-house monitoring to properly evaluate
the operation of the treatment system and develop
an on-going process control program. The tests
performed and the number of sample points used
depend on the type of plant. The frequency of
sampling depends on the raw water source, its
variability in quality, and the importance of the
parameter being tested. Below is an example of a
comprehensive monitoring program for a
conventional surface water treatment plant.
Sanitary Deficiencies for Monitoring
and Laboratory Testing
1. Is adequate monitoring in place?
The operator should have an in-house
monitoring program in place and should be
performing the monitoring required to comply
with all provisions of the SDWA.
2. Is the operator following proper
procedures?
The inspector may observe the operator's
technique in collecting samples and performing
analyses. The operator should follow correct
procedures for calibrating the test equipment
and for performing the test itself. For example,
the operator must periodically check secondary
turbidity standards against primary standards.
Example of a Comprehensive Monitoring Program for a Conventional
Surface Water Treatment Plant
Raw
Water
C/F
pH, Alk, Turb, Jar Test, Fe, Mn, Temp
pH, Alk
Sedimentation
Filtration
pH, Alk, Turb, Fe, Mn
pH, Alk, Turb, Fe, Mn,
CI2, Bacti, Fl
9-2
-------
Chapter 9 - Monitoring/Laboratory Testing
3. Are testing facilities and equipment
adequate?
The owner must provide the operator with
adequate test equipment to implement a
comprehensive monitoring program. The
inspector should verify that all test equipment
used is working properly. The laboratory itself,
in terms of space and environment, should be
adequate for the test equipment being used.
On-line monitoring equipment, such as
turbidimeters, pH meters, and chlorine residual
analyzers, must be checked and calibrated
regularly to ensure accurate performance.
The inspector should ensure that only the
correct chemical reagents for each application
are being used with the test equipment. The
reagent containers should be clearly marked
with name of the reagent and the date of its
preparation. Manufacturer-prepared reagents
should be discarded when the expiration date is
reached.
4. Are records of the monitoring program
adequately maintained?
The results of the monitoring program should
be maintained in an organized recordkeeping
system.
5. Does the operator chart the results?
The operator should plot trends on graph paper
or with a computer. This enables the operator
to see the relationship in treatment changes.
For example, as more chlorine is added, iron
levels go down, or as lime is added, pH goes
up.
6. Are treatment adjustments based on
laboratory results?
The inspector should determine what action is
taken based on the test results. The operator
should understand the importance of the test
results as they relate to the performance of the
treatment plant.
7. Are certified laboratories used when
required?
In some states, the results of some tests are not
valid unless they are performed by a certified
laboratory or certified laboratory technician.
9-3
-------
Utility
Management
The operation and maintenance (O&M) of any
water system ultimately depends on management.
Management is the process that provides funding
and support (administrative, personnel, and
purchasing) to ensure continued, reliable operation
through adequate staffing, operating supplies, and
equipment repair and replacement.
Learning Objectives
Upon successfully completing this chapter, learners
should be able to evaluate the management of a
small water supply system. Specifically, they
should be able:
To identify and evaluate key components of
a water system's management organization.
To identify the plans necessary for
compliance and long-term capacity.
To evaluate personnel staffing: numbers,
skills, certification, training, and safety.
To identify the key components necessary
for reliable system operations.
To evaluate in general terms the system's
managerial and financial capacity for long-
term reliability.
Data Collection
The inspector should obtain as much of the
following information about the water system as
possible before the sanitary survey inspection. If
the inspector is unable to do so, however, the
information and data may be obtained during the
inspection.
Previous sanitary survey reports.
Correspondence.
Compliance monitoring results.
Compliance record.
Plans on file (e.g., source protection,
sampling, emergency and contingency,
cross-connection control, and repair,
replacement, future expansion).
Regulations and Standards to
Consider
Safe Drinking Water Act.
Pertinent monitoring requirements.
Applicable ground water disinfection
requirements.
Capacity development guidance.
The system's Consumer Confidence Report.
Minimum operator certification
requirements.
Utility Management
Basic Information
The management of the water system does not, in
itself, appear to represent a sanitary risk to the
quality of the water. However, there are several
aspects of management that will ultimately affect
the overall capabilities of the system.
10-1
-------
How to Conduct a Sanitary Survey
The management of a small system may be as
small as a single individual serving as the operator
and manager. Or, it may be a hierarchy of elected
officials and municipal employees who approve
budget requests, make purchases, and plan for
infrastructure repairs and replacements to ensure
the long-term adequate, reliable, and safe
production, storage, and distribution of potable
water. Make sure you are working with the most
effective and responsible level of management.
Sanitary Deficiencies for Utility
Management
In performing a sanitary survey, the following five
areas of utility management contribute to sanitary
deficiencies.
Organization. Management of a small water
system often involves only one or two key
individuals: the operator and the owner or elected
official who is ultimately responsible for the
system's O&M. One advantage of a small
management team is the ability to identify the
individual in charge and to provide information to
that person. However, the workload may far exceed
the staffing capabilities. More complicated
management hierarchies improve individual
workloads but also increase the opportunity for
miscommunication and inadequate information
collection and dissemination.
Whatever its form, management can have a
profound effect on the reliability of a system.
Managers must have a working knowledge of the
compliance requirements that apply to their system.
Staff must be empowered to make operating
decisions and must be supported by management
responsive to resource needs.
Information collection and management is also
important. Activities range from tracking operating
expenses and locating valves on a distribution map,
to maintaining a record of breaks and repairs and a
log of customer complaints. Information of this
nature is critical for planning and budgeting for the
next year, as well as the next decade.
Planning. Planning is often a challenge for many
systems. The following plans are important to
many public water systems:
Source protection.
Monitoring.
Emergency or contingency.
Distribution flushing.
Operation and maintenance.
Cross-connection control.
There are also safety programs with which the
system must comply. Other equally critical plans
include an annual budget and a 10-year capital
improvement plan (CIP) to address repair,
replacement, and future expansion.
Personnel. Personnel issues include adequate
numbers of skilled operations staff, compliance
with state certification requirements, training, and
safety.
Operations. Management must first provide the
facilities and equipment required to operate reliably
and in compliance with all application regulations.
Written standard operating procedures ensure
reliability from one operator to the next.
Finance. Financing addresses the day-to-day
operating budget, future repair and replacement,
and future expansion. Conservation offers the
opportunity to minimize demands on the system,
protect source water quantity, reduce chemical and
electrical costs, and promote the longevity of the
system.
Reviewing these five areas will also help address
the three elements of managerial capacity and the
three elements of financial capacity.
Elements of Managerial
Capacity
Ownership accountability
Staffing and organization
Effective external linkages
Elements of
Financial Capacity
Revenue sufficiency
Fiscal controls
Credit worthiness
Although much of the information to address these
issues can be collected during the sanitary survey,
some aspects of managerial and financial capacity
may not be evident from an inspection and a
conversation with the operator. Fully assessing
capacity in these areas may require a meeting with
the water system's manager or governing authority
and additional review of financial documents. The
questions in this chapter should enable you to make
10-2
-------
Chapter 10 - Utility Management
at least a preliminary assessment of managerial and
financial capacity.
Organization
A dministration
1. Who owns the public water system?
The system representative should be able to tell
you who owns the public water system and
should be able to provide documentation of
ownership.
2. Is there a formal organizational chart?
This chart can give the inspector a much
clearer view of how the utility is organized and
who is responsible for each portion of the
utility. When there is no organizational chart,
operators often may be unsure of whom to go
to for decisions, what the normal lines of
communications are, and what their job
responsibilities are.
3. Does the operating staff have authority to
make required operation, maintenance, or
administrative decisions affecting the
performance and reliability of the plant or
system?
Determine if there are any established
administrative policies that limit the decision-
making authority of the operations staff and
adversely affect plant performance. Examples
include the lack of authority to adjust the
chemical feed, hire an electrician, or purchase
a critical piece of equipment, as well as the
lack of support for training and insufficient
plant funding.
4. Are administrators familiar with SDWA
requirements and system needs?
Key managers should be familiar with the
SDWA requirements that apply to their system.
They should learn about system needs through
plant visits and frequent discussions with
operators. Lack of first-hand knowledge may
result in poor plant performance, poor staff
morale, and poor budget decisions, as well as
limited support for system modifications.
5. Is there a formal and adequate planning
process?
The lack of long-range plans for facility
replacement, alternative sources of water, and
emergency response can adversely affect the
system's long-term performance. Planning is
addressed later in a separate section of this
guide.
Information Management
1. Does the utility manage its information?
Information management includes formal
systems and written procedures for:
Cataloging, sorting, and storing maps and
as-built plans.
Updating maps.
Handling and tracking customer complaints.
Handling and tracking line breaks, repairs,
and replacements.
Identifying, collecting, analyzing, and
updating key operational and required
monitoring data.
Developing and maintaining standard
operating policies and procedures.
Developing and maintaining maintenance
records.
Developing and maintaining financial
records.
The information listed above is essential to
addressing existing problems and planning for
future needs.
2. Does the utility track and identify typical
operating parameters such as:
Unaccounted-for water
Cost per unit of production of water
When utilities track and share this type of
information among operations personnel and
the governing body, it is a good indication that
10-3
-------
How to Conduct a Sanitary Survey
the utility is focused on obtaining results and 3.
meeting customer needs.
This type of information justifies decisions and
promotes compliance with SDWA and industry
suggested practices for water conservation and
quality.
3. Does the utility track finances, operational
data, and maintenance practices on a
computer?
While a computer is not a requirement, it
facilitates storage of data that can be presented
to support management decisions.
Internal and External Communication
1. Is there effective communication between
key management staff, operations staff,
and the state primacy agency?
Difficulties here can account for problems with
the budget and personnel policy. They also can
account for poor relations between
management and staff and between the
organization and the state enforcement agency. 4.
Inspectors should review previous
correspondence to determine the responsiveness
of the system and should ask questions to
confirm observations.
2. What is the level of cooperation between
the system and other agencies and
organizations?
To be successful, a utility needs to cooperate
with associated utilities and enforcement 5.
agencies. Examples include cooperation with
water conservation agencies, with one-call
(Call Before You Dig) groups such as the
APWA underground utility coordinating
committee, and with county and state agencies
involved in land-use planning and long-term
water use, conservation, and water needs. This
cooperation also involves active membership in
professional groups such as AWWA and
APWA. A second but also important area is
cooperation between the utility and the state
primacy agency. A history of poor relations
may indicate that the utility has had difficulty
complying with requirements.
What is the level of cooperation between
the system and the local fire department?
This is often difficult to determine directly.
However, you may ask questions such as:
What role does the fire department play in
inspecting fire hydrants, flushing fire
hydrants, and determining the type and
location of new fire hydrants?
What role does the fire department play in
the system's emergency plan as a first
responder for chemical spills or accidental
releases?
What is the policy and procedure for
notifying the fire department when a hydrant
is out of service?
What is the notification procedure when the
fire department uses a fire hydrant?
What is the role of the fire department in
determining construction needs?
Is there a customer complaint system and
an ongoing public information program?
Lacking a system to keep track of and respond
to customer complaints may indicate
ineffective communication with customers. Not
having an ongoing public information program,
including a Consumer Confidence Report, may
indicate that the system does not provide
adequate information to its customers.
Does the system have an adequate source
of capital for operations, maintenance, and
capital projects? Is the system eligible for,
and has the system received, state or
federal funding?
It is important for a system to have adequate
returns or access to capital (from public or
private sources) to repair or replace
infrastructure and to address emergencies.
Lack of access, or exhaustion of available
funding, may indicate problems with the
system's managerial and financial capabilities.
However, systems should not borrow funds for
normal O&M functions except in emergencies.
10-4
-------
Chapter 10 - Utility Management
Federal and state funding programs generally
provide lower interest rate loans to systems, in
particular, smaller systems. Limited federal
and state grant funding is also available,
particularly for small, more rural systems.
However, many of the programs have
eligibility requirements and fund only certain
types of systems and certain types or categories
of projects. For example, some states have
limited Drinking Water State Revolving Fund
(DWSRF) loans to publicly owned systems.
Also, DWSRF monies cannot be expended for
monitoring, operation, and maintenance.
It is important that all systems, particularly
small systems, establish a credit rating that will
allow them access to funds if an emergency
occurs or an unexpected cost arises. Financial
institutions will look at the health of the system
as measured through indicators, ratios, and
ratings; previous credit records; and proof of
assurance of repayment when determining
whether a system is a good credit risk.
6. Is the staff active in industry and
professional organizations?
Such participation is important because it
improves the system's awareness of available
external resources, new technology, and
advances in the field.
Planning
1. Is an emergency or contingency plan
available and workable?
The utility should have an emergency or
contingency plan that outlines what actions will
be taken and by whom. The emergency plan
should meet the needs of the facility, the
geographical area, and the nature of the likely
emergencies. Conditions such as storms,
floods, and major mechanical failures should
be considered. The emergency plan should be
updated annually, and larger facilities should
practice implementation of the plan annually.
2. Are written, workable plans available for
the areas listed below?
Source protection.
Sampling and monitoring.
Emergency or contingency.
Hazard communication plan (if required).
Cross-connection control.
Repair, replacement, and future expansion
(capital improvement).
Distribution system flushing program.
Personnel
Staffing
1. Are there sufficient personnel?
There should be enough personnel to provide
for operation during evenings, weekends,
vacations, and illness. The number of operators
depends on the type and size of the treatment
process. A good indication of the adequacy of
personnel is if proper O&M procedures can be
accomplished with little or no overtime.
2. Is the staff qualified?
The staff should have the appropriate aptitude,
education, and level of certification to perform
the job correctly.
Systems must comply with state requirements
for certification. Proof of certification should
be prominently displayed or otherwise made
available to the inspector. Certification at the
correct level is assumed to be one major
measurement of staff qualifications.
3. Are personnel adequately trained?
To properly operate a system, personnel must
be adequately trained. There should be an
ongoing training program. Personnel can be
trained in various ways, including in-house
training conducted by more experienced
personnel and state-sponsored training.
Correspondence courses, such as Water
Treatment Plant Operation, Water
Distribution System Operation and
Maintenance, and Small Water System
Operation and Maintenance from California
State University, Sacramento School of
Engineering, and AWWA courses are also
10-5
-------
How to Conduct a Sanitary Survey
available. The inspector can solicit information
from operators about process controls,
maintenance requirements, and safety to help
determine the adequacy of their training.
Safety Program
1. Have the operators been adequately
trained in safety procedures and
equipment?
The safety of the operators and the inspector is
of paramount importance. Injury to any of
them can adversely affect the system. Although
sanitary survey inspectors are not safety
experts, conversations with the operators and
managers of the system will enable the
inspector to determine if a safety program is in
place. Adequate safety training and safety
equipment are essential. Management should
be able to give the inspector a list of training
activities and training attendance records.
Proper safety equipment should be on site and
adequately maintained. Examples of necessary
equipment include, but are not limited to, self-
contained breathing apparatus (SCBAs),
chlorine cylinder repair kits, eye-wash stations,
and fire extinguishers.
2. Has the utility complied with OSHA safety
requirements?
OSHA requirements include having a hazard
communication program, lockout/tagout, and
confined space entry training and procedures.
The fact that Material Safety Data Sheets
(MSDSs) are available and the operators know
where they are can be taken by the inspector as
some evidence of compliance with OSHA
requirements. The inspector should determine
if there is documentation of the required
training in how to read the MSDSs, how to use
hazardous materials, and how to handle
emergencies associated with hazardous
materials.
3. Does the utility have a good safety record?
The inspector should review past safety
records and determine the accident severity rate
and the frequency rate for the previous 5 years.
A poor safety record can be a good reflection
of personnel problems, poorly maintained
equipment, or lack of attention to safety by
management. A poor safety record also can
have a negative effect on water quality. It can
reduce the number of personnel and the number
of trained personnel available to handle normal
conditions and to resolve problems.
Operations
Operating Procedures
1. Is there an overall O&M manual for the
facility?
In addition to the standard O&M manual,
manufacturers' literature should be available
for all pieces of equipment. All of this
information, and the as-built plans of the
facility, should be on site or readily available.
Equipment cannot be properly maintained
without adequate manuals and manufacturers'
literature.
2. Has a program of standard operating
procedures (SOPs) been implemented at
the facility?
Operations and management personnel should
be queried about the availability of O&M
manuals, manufacturers' literature, and SOPs.
SOPs are essential to ensure consistent plant
operations from one operator to the next.
Facilities and Equipment
1. Is there sufficient storage for spare parts,
equipment, vehicles, traffic control
devices, and supplies?
The inspector should assess storage facilities
for adequacy, housekeeping, and general
appearance. The appearance of the facilities is
often a reflection of the importance that
management places on the people who work in
the system.
2. Are the facilities and equipment of the
system adequate?
Inadequate facilities and equipment, such as
undersized pumps, lack of redundancy, and
poor maintenance, can interfere with the
production of potable water. Buildings and
10-6
-------
Chapter 10 - Utility Management
structures must be sound and provide
appropriate security. Equipment must be
maintained according to manufacturers'
specifications and should be properly sized for
the job.
3. Are there adequate facilities for system
personnel?
Such facilities include space for crew meetings,
a lunch room, a rest room, and individual
lockers. Check for adequacy and cleanliness.
Finance
In addition to looking specifically at a water
system's finances, the inspector should be aware
that other aspects of the sanitary survey can
indicate the state of the system's finances and its
financial capacity. For example, infrastructure
deficiencies may be due not only to a lack of
technical capability but to a lack of financial
capacity as well. Without sufficient revenue, the
system will not be able to cover the costs of source
water protection, treatment, storage facility
maintenance, and system upgrades.
1. Are the financing and budget satisfactory?
What is the estimated income? What are
the estimated expenses?
The system should have sufficient revenue for
operation, maintenance, and future
replacements. These funds should not be
commingled with other accounts. The system
should operate on its own revenues and should
have a sinking fund for major equipment
replacement.
An inability to answer the questions above
indicates a lack of financial planning necessary
for financial capacity. If answers are available,
but they indicate that system revenues do not
cover costs, the system lacks financial
capacity. This lack may pose risks if
insufficient funding results in an inability to
maintain and upgrade the facility, pay
appropriate salaries, or maintain sufficient
stocks of spare parts, chemicals, or equipment.
2. Are funds focused in the correct
direction?
Determine if the manner in which available
funds are used causes problems in obtaining
needed equipment or staff. In addition,
determine if funds are spent on lower priority
items while higher priority items are unfunded.
3. Are there sufficient funds for staff
training?
AWWA recommends a training budget equal to
5 percent of the workers' salaries.
4. Are projected revenues consistent with
projected growth?
If a system's revenue projections are not
consistent with its projected growth-if revenue
is not going to keep pace with system size-
eventually there will be insufficient revenue to
operate the system.
5. Does the system have formal accounting
systems and written procedures for
financial records?
If the system does not have formal systems and
procedures for financial recordkeeping, it is
likely that appropriate accounting and financial
planning methods are not being followed.
6. Does the system have budget and
expenditure control procedures?
Although it is important that water system staff
have the authority to purchase supplies and
equipment as they are needed, it is equally
important that there be standard procedures for
budget and expenditure control. A follow-up
question might be to ask the representative
what they do when they need to purchase
something for the system. By discussing a real
example, you might discover that the system
representative was unsure of the terms used in
the first question and the system does, in fact,
have purchase order procedures and
authorization requirements, and therefore
procedures for budget and expenditure control.
10-7
-------
How to Conduct a Sanitary Survey
7. What are the utility's debt service
expenses?
If a system's debt service expenses are
exceptionally high, the system either has a
large level of debt, or it is paying a high
interest rate on its debt. This situation could
mean that the system has exhausted its access
to capital, or it has a poor credit rating and is
forced to pay higher interest when it borrows.
In either case, high debt service expenses
indicate a lack of financial capacity.
8. Does the system have a water
conservation policy or program?
Water rates that promote conservation can
yield savings. Conservation reduces the
demand on the source, reduces chemical and
electrical costs, and minimizes wear and tear
on equipment such as pumps. In many cases a
system can avoid the need for plant expansions
by implementing an effective water
conservation program.
10-8
-------
Appendix A
Suggested References
1. At America's Service - Karl Albrecht
Available from:
Warner Books
New York, NY 100020
www.twbookmark.com
2. AWWA B600-78: Standard for Powdered
Activated Carbon
Available from:
American Water Works Association
(AWWA)
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax:(303)347-0804
www.awwa.org/bookstore
3. AWWA B604-74: Standard for Granular
Activated Carbon
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax:(303) 347-0804
www.awwa.org/bookstore
4. Basic Science Concepts and Applications
Reference Handbook
Available from:
AWWA'
6666 W. Quincy Avenue
Denver, CO 80235
(800)926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
5. Chemistry of Water Treatment - Second
Edition
Available from:
Lewis Publishers, Inc.
2000 Corporate Blvd, NW
Boca Raton, FL 33431
(800) 272-7737
Fax: (407) 998-0555
6. Construction of Distribution Systems
Available from:
ACR Publications
1298 Elm St. SW
Albany, OR 97321
(541)928-6199
(800)433-8150
Fax:(541)926-3478
www.acrp.com
7. Cross-Connection Control Manual
Available on line from:
The U.S. Environmental Protection Agency
www.epa.gov.safewater/
crossconnection .html
8. Distribution Systems
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
A-1
-------
How to Conduct a Sanitary Survey
9. Electrical Fundamentals for Water and
Wastewater
Available from:
ACR Publications
1298 Elm St. SW
Albany, OR 97321
(541)928-6199
(800)433-8150
Fax: (541)926-3478
www.acrp.com
10. Environmental Engineering and Sanitation,
4th Edition - by Joseph A. Salvato
Available from:
John Wiley & Sons, Inc.
I Wiley Drive
Somerset, NJ 08873
(800) 225-5945
Fax: (732) 302-2300
www.wiley.com
11. Guidance for Management of Distribution
System and Operation and Maintenance
Available from:
AWWARF
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303)347-0804
www.awwa.org/bookstore
12. Guidance Manual for Conducting Sanitary
Surveys of Public Water Systems; Surface
Water and Ground Water Under the Direct
Influence
EPA Publication No. EPA 815-R-99-016
www.epa.gov/safewater/mdbp/pdf/sansurv/
sansurv.pdf
13. Guidance Manual for Compliance with the
Filtration and Disinfection Requirements
for Public Water Systems Using Surface
Water
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
14. Guidance Manual for Maintaining
Distribution System Water Quality
Available from:
AWWARF
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
15. Integrated Design of Water Treatment
Facilities - Second Edition
Available from:
John Wiley & Sons, Inc.
1 Wiley Drive
Somerset, NJ 08873
(800) 225-5945
Fax: (732) 302-2300
www.wiley.com
16. Introduction to Small Water Systems
Available from:
ACR Publications
1298 Elm St. SW
Albany, OR 97321
(541)928-6199
(800)433-8150
Fax:(541)926-3478
www.acrp.com
17. Introduction to Utility Management
Available from:
ACR Publications
1298 Elm St. SW
Albany, OR 97321
(541)928-6199
(800)433-8150
Fax:(541)926-3478
www.acrp.com
18. Introduction to Water Distribution, Volume
III
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstorc
A-2
-------
Appendix
19. Introduction to Water Treatment, Volume II
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303)347-0804
www.awwa.org/bookstore
20. Introduction to Water Quality Analysis,
Volume IV
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
21. Introduction to Water Sources
Transmission, Volume 1
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
22. Maintenance Management
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
23. Manual of Individual Water Supply Systems
Available from:
National Technical Information Service
U.S. Department of Commerce
5285 Port Royal Road
Springfield, VA 22161
(800)553-6847
Fax: (703)321-8547
Stock No. PB85-242279
24. A Manual of Instruction for Water
Treatment Plant Operators
Available from:
Health Education Services, Inc.
P.O. Box 7126
Albany, NY 12224
(518)439-7286
Fax:(518)439-7022
www.hes.org
25. Manual of Treatment Techniques for
Meeting the Interim Primary Drinking Water
Regulation; EPA 600/8-77-005
Available from:
USEPA-NSCEPI
P.O. Box 42419
Cincinnati, OH 45242
(800)490-9198
Fax:(513)489-8695
www.epa.gov/ncepihom/ordering.htm
26. Manual of Water Utility Operations 8th
Edition
Available from:
Texas Water Utilities Association
1106 Clayton Lane, Ste 101 East
Austin, TX 78723
(888) 367-8982
Fax: (512)459-7124
www.twua.org/publications.htm
27. National Primary Drinking Water
Regulations (40 CFR part 141)
Available on line from:
The U.S. Environmental Protection Agency
www.epa.gov/safewater/regs/cfrl41.pdf
28. National Secondary Drinking Water
Regulations (40 CFR part 143)
Available on line from:
The U.S. Environmental Protection Agency
www.epa.gov/safewater/regs/cfrl43.pdf
29. Occurrence and Removal of VOC's from
Drinking Water
Available from:
AWWA'
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax:(303)347-0804
www.awwa.org/bookstore
A-3
-------
How to Conduct a Sanitary Survey
30. O&M of Chlorine Systems
Available from:
ACR Publications
1298 Elm St.
SW Albany, OR 97321
(541)928-6199
(800)433-8150
Fax:(541)926-3478
www.acrp.com
31. Opflow, Volume 12, No. 5, May 1986
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/communications/opflow
32. Pathogen Intrusion into the Distribution
System
Available from:
AWWARF
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
33. Planning for an Individual Water System
Available from:
American Association for Vocational
Instructional Materials
Engineering Center
220 Smithonia Road
Waterville, GA 30683
(800) 228-4689
Fax: (706) 742-7005
www.aavim.com
34. Pumps and Pumping
Available from:
ACR Publications
1298 Elm St. SW
Albany, OR 97321
(541)928-6199
(800)433-8150
Fax:(541)926-3478
www.acrp.com
35. Recommended Standards for Water Works
(Ten States Standards)
Available from:
Health Education Services, Inc.
P.O. Box 7126
Albany, NY 12224
(518)439-7286
www.hes.org
36. Recommended Practice for Backflow
Prevention and Cross-Connection Control
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800)926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
37. Rehabilitation of Water Mains - Manual of
Supply Practices - Second Edition
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
38. Safe Drinking Water Advisor: A Compliance
Assistance Resource (CD)
Available from:
AWWARF
6666 W. Quincy Avenue
Denver, CO 80235
(800)926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
39. Small Water System Operation &
Maintenance 4th Edition
Available from:
Office of Water Programs
California State University, Sacramento
6000 J Street
Sacramento, CA 95810
(916)278-6142
Fax:(916)278-5959
www.own,csus.edu/OWPHome.html
A-4
-------
40. Standards for the Disinfection of Pipe
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
41. The Safe Drinking Water Act Handbook for
Water System Operators
Available from:
AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800) 926-7337
Fax: (303) 347-0804
www.awwa.org/bookstore
42. Water Distribution System Operation &
Maintenance
Available from:
Office of Water Programs
California State University, Sacramento
6000 J Street
Sacramento, CA 95810
(916)278-6142
Fax: (916)278-5959
www.owp.csus.edu/OWPHome.html
43. Water Systems Handbook - Eleventh
Edition
Available from:
Water Systems Council
1101 30th Street, NW
Suite 500
Washington, DC 20007
(202) 625-4387
Fax: (202) 625-4363
www.watersystemscouncil.org
Appendix
44. Water Treatment Plant Design, Third
Edition, prepared jointly by the American
Water Works Association, Conference of
State Sanitary Engineers, and American
Society of Civil Engineers
Available from:
Data Processing Department, AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800)926-7337
Fax:(303)347-0804
www.awwa.org/bookstore
ASCE Publications
1801 Alexander Bell Drive
Reston, VA 20191
(800) 548-2723
www.pubs.asce.org/pubshoml .html
45. Water Treatment Plant Operations, Volume I
- Fourth Edition
Available from:
Office of Water Programs
California State University, Sacramento
6000 J Street
Sacramento, CA 95810
(916)278-6142
Fax: (916) 278-5959
www.owp.csus.edu/OWPHome.html
46. Water Treatment Plant Operations, Volume
II-Third Edition
Available from:
Department of Civil Engineering
California State University, Sacramento
6000 J Street
Sacramento, CA 958 10
(916)278-6142
Fax:(916) 278-5959
www.owp.csus.edu/OWPHome.html
47. Water Quality and Treatment: A Handbook
of Public Water Supplies: American Water
Works Association, Fifth Edition, McGraw-
Hill, 1990.
Available from:
Data Processing Department, AWWA
6666 W. Quincy Avenue
Denver, CO 80235
(800)926-7337
Fax:(303)347-0804
www.awwa.org/bookstore
Order No. 10008
A-5
------- |