Interim Publication of Manuscript
JULY. 1978
manual
SMALL WATER SYSTEMS
SERVING THE PUBLIC
correlated with
NATIONAL DRINKING WATER REGULATIONS
CONFERENCE OF STATE SANITARY ENGINEERS
in cooperation with
OFFICE OF DRINKING WATER
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. O.C., 20460
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THIS DOCUMENT HAS BEEN REPRODUCED DIRECTLY
FROM THE MANUSCRIPT IN LIMITED QUANTITIES
TO MEET INTERIM NEEDS. IT IS AVAILABLE IN
LIMITED QUANTITIES THROUGH THE CONFERENCE
OF STATE SANITARY ENGINEERS, MEREDITH H.
THOMPSON, EXECUTIVE SECRETARY, 1 DEERFIELD
DRIVE, TROY, NEW YORK, 12180 OR THE OFFICE
OF DRINKING WATER, U.S. ENVIRONMENTAL
PROTECTION AGENCY, (WH 550), WATERSIDE MALL,
EAST TOWER, 4th and M STREETS SW, WASHINGTON,
D.C., 20460
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Interim Publication of Manuscript
JULY, 1978
manual
SMALL WATER SYSTEMS
SERVING THE PUBLIC
correlated with
NATIONAL DRINKING WATER REGULATIONS
CONFERENCE OF STATE SANITARY ENGINEERS
FRANK R. LIGUORI, PE, Technical Writer
in cooperation with
OFFICE OF DRINKING WATER
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C.. 20460
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PREFACE
This Manual was developed through the Conference of State Sanitary Engineers
under U.S. Environmental Protection Agency Grant No. T900624010, to fulfill a
need for a manual covering small water supply systems serving the public.
The Manual is designed to provide guidance in the planning, design, develop-
ment, maintenance, operation and evaluation of small water systems and is
correlated with the National Drinking Water Regulations. It is prepared as
a service to:
- Owners and operators of public water systems serving small communi-
ties of about 50 connections or less and the non-community type
systems.
- The design engineer who may be called upon to design small water
systems.
- State and local enforcing agencies as a tool to assist in
evaluation and inspection responsibilities.
The Manual was prepared by Frank R. Liguori, P.E., Sanitary Engineer,
Ithaca, NY, who served as the technical writer under the guidance of a
special C.S.S.E. Task Group. The Task Group reviewed the various drafts,
provided technical advice and material, and approved this final manuscript.
The Task Group included the following:
Irving Grossman, Engineer
First Phase Chairman
C.S.S.E. Task Group
Chief, Bureau of Residential
Recreation Sanitation
NYS Department of Health
Albany, NY 12237
David Cochran, Engineer
Bureau of Environmental Health
Texas Department of Health
Austin, Texas 78756
Meredith H. Thompson, Engineer
Executive Secretary C.S.S.E.
Second Phase Chairman
C.S.S.E. Task Group
Troy, NY 12180
Clarence L. Young, Engineer
Sanitary Engineering Services
California Department of
Health Services
Berkley, CA 94704
Joseph Dennis, Engineer
Division of Health Service
Department of Human Resources
State of North Carolina
Raleigh, NC 27602
Donald Keech, Engineer
Bureau of Environmental Health
and Occupational Health
Michigan Department of Public Health
Lansing, MI 48909
Victor Wilford, Engineer
Environmental Health Services
West Virginia Department
of Health
Charleston, WV
330!
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The Manual was also approved by the C.S.S.E. Executive Board consisting of:
Oscar Adams, Chairman (State of Virginia)
John E. Jenkins, Chairman-Elect (State of South Carolina)
James F. Coerover, Secretary-Treasurer (State of Louisiana)
Joseph D. Brown, First Vice-Chairman (State of Mississippi)
Laverne Hudson, Second Vice-Chairman (State of Illinois)
Robert G. McCall, Past Chairman (State of West Virginia)
The Conference of State Sanitary Engineers acknowledges the guidance and
input provided by the U.S. Environmental Protection Agency including:
Victor Kim, Assistant Deputy Administrator; John Mannion, Special Assistant;
George C. Kent, Sanitary Engineer, Office of Drinking Water; and Peter Y.
Bengtson, Sanitary Engineer, Office of Drinking Water. However, participation
by EPA does not imply that the contents necessarily reflect the views or
policies of the Environmental Protection Agency, nor does the mention of
trade names or commercial products constitute endorsement or recommendation
thereof.
Material used in the preparation of the Manual was derived from many sources.
Where material is used in its direct original form or adapted from an original
publication, permission has been received for its use and credits are shown.
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MANUAL
SMALL WATER SYSTEMS SERVING THE PUBLIC
Correlated With
National Drinking Water Regulations
CONTENTS
Page
PURPOSE AND USE OF THE MANUAL 1
PART 1 PLANNING-DESIGN-DEVELOPMENT
CHAPTER 1 WATER MEASURING TERMS AND UNITS
- Introduction 1-1
- English and Metric Quantity Units 1-1
- Conversion Tables 1-5
- Water Quality Units 1-7
Tables: 1-1 English Units and Metric Equivalents .. 1-5
1-2 Approximate Conversions 1-6
CHAPTER 2 PLANNING, SANITARY SURVEY AND DESIGN CONSIDERATIONS
- Introduction 2-1
- Planning Elements 2-2
- Sanitary Survey of Well and Spring Sites 2-4
- Sanitary Survey of Surface Water Supplies 2-6
- Water System Design Elements 2-7
- Submitting Plans to the State Agency 2-9
CHAPTER 3 DESIGN CAPACITY OF SYSTEM COMPONENTS
- Introduction 3-1
- Estimating Basic Water Demands 3-2
- Estimating Required Capacity of Wells 3-14
- Estimating Required Capacity of Surface Supplies .. 3-15
- Estimating Required Capacity of Spring Supplies . . . 3-16
- System Pressures 3-16
- Sizing Treatment Units 3-16
- Sizing Distribution and Piping Systems 3-17
Figures: 3-1 Water Flow Demand Per Fixture
Value - Low Range 3-9
3-2 Water Flow Demand per Fixture
Value - High Range 3-9
3-3 Instantaneous Demand for Residential
Communities 3-11
3-4 Peak Demands for Mobile Home Parks .... 3-12
Tables: 3-1 Guide for Estimating Average Daily
Water Requirements 3-3
3-2 Plumbing Fixture Value 3-8
3-3 Multiplication Factors to Adjust
Demand Load to Various Delivery
Pressures 3-8
1
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Page
CHAPTER 4 SOURCES OF WATER
- Introduction 4-1
- Ground Waters 4-2
- Surface Waters 4-8
Figure: 4-1 Ground Water Aquifers 4-5
CHAPTER 5 WELL CONSTRUCTION AND DEVELOPMENT
- Introduction 5-1
- Well Site Selection 5-2
- Yield of Wells 5-3
- Types of Wells 5-6
- Well Construction 5-6
- Drilling Methods 5-7
- Well Casing and Pipe 5-11
- Well Grouting 5-12
- Well Screens 5-13
- Development of Wells 5-14
- Testing for Yield and Drawdown 5-15
- Comparison of Yield With Demands 5-16
- Well Head Covers and Seals 5-16
- Inspection and Testing of Pitless Seals 5-24
- Well Disinfection 5-29
- Bacteriological Test 5-32
- Abandonment of Wells 5-32
Figures: 5-1 Drawdown During Pumping 5-4
5-2 Water Well Record 5-10
5-3 Well Seal for Jet Pump Installation.. 5-19
5-4 Well Seal for Submersible Pump
Installation 5-20
5-5 Clamp-on Pitless Adapter for Submer-
sible Pump Installation 5-25
5-6 Pitless Unit With Concentric External
Piping 5-26
5-7 Weld-on Pitless Adapter 5-27
5-8 Pitless Adapter With Submersible Pump
for Basement Use 5-28
Tables: 5-1 Minimum Distances Between Wells and
Sources of Potential Pollution 5-3
5-2 Recommended Well Diameters 5-4
5-3 Storage Capacities of Well Casing.... 5-31
5-4 Well Disinfection Doses 5-31
CHAPTER 6 WELL PUMP SYSTEMS
- Introduction 6-1
- Selecting Pump Equipment 6-2
- Sanitary Protection of Pumping Facilities 6-5
- Installation of Pumping Equipment 6-6
- Pumphouse and Appurtenances 6-10
- Lightning Protection 6-10
- Hydro pneumatic Systems 6-13
- Gravity Storage Systems 6-28
- Disinfection of System 6-3l
2
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Page
CHAPTER 6 (Continued):
Figures: 6-1 Vertical Turbine Pump 6-7
6-2 Vertical Turbine Pump Base 6-8
6-3 Exploded View of Submersible Pump ... 6-9
6-4 Over-the-well Jet Pump Installation . 6-11
6-5 Pumphouse 6-12
6-6 Types of Storage Tanks 6-18
6-7 Typical Installation of Pressure Tank
System 6-18
6-8 Curves for Sizing Hydropneumatic
Tanks 6-26
Table: 6-1 Pump Characteristics 6-4
CHAPTER 7 DEVELOPING SPRINGS
- Introduction 7-1
- Development of Springs 7-2
- Sanitary Protection 7-4
- Storage Systems 7-4
- Disinfection 7-5
Figure: 7-1 Spring Protection 7-7
CHAPTER 8 DEVELOPING SURFACE WATERS
- Surface Waters 8-1
- Infiltration Galleries 8-3
- Raw Water Storage 8-4
- Treatment 8-5
CHAPTER 9 CHLORINATION
- Introduction 9-1
- Chlorination Methods 9-2
- Chlorination Terminology 9-6
- Factors Influencing Chlorination' 9-9
- Chlorinator Capacity 9-10
- Determining Hypochlorinator Feed Rate and
Solution Strength 9-11
- Testing for Chlorine Residuals 9-14
Figures: 9-1 Typical Hypochlorinator Installation. 9-6
9-2 Determining Required Amount of 5.25%
Bleach to Make Solution for 1.0 ppm
Feed Rate 9-13
Table: 9-1 Recommended Minimum Concentrations of
Free Chlorine Residuals 9-10
3
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Page
CHAPTER 10 TREATMENT AND CONDITIONING
- Introduction . 10-L
- Chemical, Physical and Bacteriological Examina-
tion to Help Establish Treatment Requirements.... 10-4
- Water Softening 10-4
- Iron and Manganese Control 10-7
- Other Uses of Ion Exchange Resins and Adsorbents. 10-8
- Taste and Odor Control 10-9
- Corrosion Control 10-10
- Color Removal 10-12
- Turbidity Removal 10-13
Figures: 10-1: Alkalinity Vs. pH and Corrosivity.. 10-1]
CHAPTER 11 DISTRIBUTION SYSTEM
- Introduction 11-1
- Site Conditions 11-2
- Selection of Pipe Sizes 11-3
- Pipe Materials 11-9
- Valves 11-12
- Thrust Backing and Anchorage 11-14
- Service Lines and Connections 11-16
- Separation of Water Mains and Sewers 11-17
- Disinfection 11-18
Tables: 11-1 Friction Loss in Pipes 11-8
11-2 Friction Loss in Valves and Fittings. 11-8
11-3 Characteristics of Piping 11-11
11-4 Thrust at Fittings 11-14
11-5 Safe Bearing Load of Soils 11-15
11-6 Disinfection With Chlorine Tablets.. 11-20
PART II OPERATION AND MAINTENANCE
Chapter 12 NATIONAL DRINKING WATER REGULATIONS
- Introduction 12-1
- Summary of Primary Drinking Water Regulations.... 12-2
- Siting Requirements 12-2
- Applicability 12-3
- Summary Tabulation of Monitoring Requirements 12-4
- Monitoring and Analytical Requirements 12-5
- Microbiological 12-5
- Turbidity 12-8
- Inorganic Sampling 12-9
- Organic Sampling 12-11
- Approved Laboratories 12-12
- Monitoring Consecutive Water Systems... 12-12
- Reporting, Public Notification and
Record Keeping 12-12
- Record Maintenance 12-15
4
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CHAPTER 12 (Continued):
- Secondary Drinking Water Guidelines 12-16
- Maximum Contaminate Levels 12-16
- Contaminates Considered But Not Included.... 12-20
-• Summary Tabulation 12-22
- Sampling Responsibility and Techniques 12-22
CHAPTER 13 MAINTENANCE
- Introduction 13-1
- Maintenance of Well Pumps and Controls 13-2
- Servicing Instruments 13-2
- Jet Pumps 13-2
- Submersible Pumps 13-6
- Reciprocating Pumps 13-12
- Centrifugal Pumps 13-17
- Turbine Pumps 13-17
- Hydropneumatic Systems 13-18
- Protection of Electrical Components and Shock 13-19
- Gauges 13-20
- Treatment Equipment 13-21
- Distribution System 13-22
- Corrosion Control 13-25
- Well Yield Rehabilitation 13-26
Tables: 13-1 Trouble Shooting the Jet Pump 13-3
13-2 Trouble Shooting the Submersible
Pump 13-7
13-3 Trouble Shooting the Reciprocating
Pump 13-13
CHAPTER 14 RECORD KEEPING
- Introduction 14-1
- Engineering Plans and Specifications 14-3
- Operational Records i 14-3
- Maintenance Records 14-4
- Legal Requirements 14-6
Figures: 14-1 Equipment and Inspection and Repair
Record Form 14-7
14-2 Form for Report of Operation of
Hypochlorinator 14-8
CHAPTER 15 EMERGENCIES AND SPECIAL PROBLEMS
- Introduction 15-1
- Emergency Disinfection 15-2
- Cross-connections 15-4
- Contamination By Petroleum Products 15-8
- Contamination With Other Chemicals 15-9
Table: 15-1 List of Plumbing Hazards 15-6
5
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Page
PART III APPENDICES
APPENDIX A - GLOSSARY A-l
APPENDIX B - LIST OF STATE AGENCIES AND EPA REGIONAL OFFICES B-l
APPENDIX C - REFERENCES AND SELECTED BIBLIOGRAPHY C-l
APPENDIX D - TECHNICAL REPORT DATA D-l
6
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PURPOSE AND USE OF THE MANUAL
The owner of a water system serving the public has a legal responsibility
to provide a safe, potable and adequate supply of water at all times. In 1974,
the Congress of the United States passed the Safe Drinking Water Act as a means
of assuring safe public water systems and directed the Environmental Protection
Agency to establish nationwide drinking water regulations. All public water
systems are regulated by the provisions of the National Safe Drinking Water Act
and the National Drinking Water Regulations^ adopted by the U.S. Environmental
Protection Agency pursuant to the Act. Individual State agencies which accept
and qualify for enforcement responsibilities will enforce the regulations and
may also enforce certain regulations of their own. (See Appendix B for a
listing of State agencies.)
Some of the pertinent definitions follow:
Public Water System means a system which provides piped water to the
public for human consumption, if the system has at least fifteen (15) service
connections or regularly serves an average of at least twenty-five (25) indivi-
duals at least sixty days out of the year. There are basically two types of
public water systems, community and non-community.
Community Water System means a public water system which serves at least
fifteen (15) service connections used by year around residents or regularly
serves twenty-five (25) year around residents.
(1) National Interim Primary Drinking Water Regulations, U.S. Environmental
Protection Agency, available through State enforcing agencies. See
Chapter 12 for more details.
1
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Non-Community Water System means a public water system that is not a
community water system, basically one that serves the transient public.
Examples of the classes and types of water systems regulated under
the Act and the Drinking Water Regulations are listed below.
Community water Systems
Municipal systems and public water utilities
Mobile home parks
Condominiums
Residential institutions and schools, including hospitals, nursing homes,
homes for the aged, colleges, etc.
Housing developments, public and private
Multi-family housing complexes (all varieties)
Non-Community Water Systems (with separate water systems)
Motels-hotels-resort areas Campgrounds
Schools (non resident) Highway rest areas
Restaurant and other food service places Marinas
Parks Airports
Recreation areas Medical Care Facilities
Migrant labor and construction camps Shopping Centers
Children and adult camps Office and commercial buildings
Gasoline service stations Public buildings and public assembly
Industries Social and recreation clubs
Churches Swimming pools and beaches
| It is the purpose of this Manual to provide planning, design, develop-
ment, operation and maintenance guidance for the numerous public water systems
serving the non-community grouping and the small community systems serving up
to about fifty connections. In order to increase its usefulness, the Manual
is correlated with the National Drinking water Regulations.
2
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Other manuals and textbooks are readily available to provide guidance
for the larger municipal (community) water systems. In addition, pamphlets
are readily available to assist the individual home owner and the farmer in
developing small individual water systems. However, much of the available
published information on the small public water systems which fall
between these extremes is scattered in a variety of miscellaneous publica-
tions. This Manual brings together some of the information into a
single volume. It is written primarily to meet the needs of owners and
operators of small public water systems throughout the nation. But it is
also hoped that the Manual will be of value to the professional engineer
who will be called upon to design these small water systems and the water
technicians who will assist in administering surveillance programs for
federal and state agencies. To increase its usefulness, the Manual includes
design capacity guidance for the various components of a water system and
guidance on the sanitary protection of the system.
More often than not small public water systems utilize wells with
gravity storage reservoirs, or hydropneumatic systems, with comparatively
small distribution systems without provisions for fire flow protection.
These are discussed in some detail. Occasionally, springs, infiltration
galleries or surface water sources are utilized and these too are covered
but in less detail.
The information provided in the Manual represents a broad consensus
of acceptable water supply practices throughout the nation. However, con-
ditions vary over the expanse of the country and the water purveyor is encour-
aged to consult with the individual State regulatory agencies for specific
requirements and criteria which may be applicable within a particular State.
The Environmental Protection Agency has authorized certain counterpart State
agencies (which qualify and accept a primary enforcement role) to assume the
3
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basic responsibility for surveillance and enforcement of the Act arid the
Drinking Water Regulations. The current listing of these State agencies
may be found in Appendix B. If no State agency is listed, the applicable
EPA Regional Office should be consulted. Companion State regulations also
apply. It is particularly important to consult with the State agency for
special requirements on design, plan submission, sampling and testing,
record keeping, reporting, construction permits and operating permits.
The Manual is divided into three parts with each part further
subdivided into chapters. An introduction provides a synopsis of the con-
tent of each chapter. The Table of Contents provides a sequential listing
of the contents of each Chapter.
PART I ~ PLANNING, DESIGN AND DEVELOPMENT
The chapters in this part follow the logical sequence of planning,
design and development of a new water system. Guidance is also provided
for expansion of an existing system or the addition of treatment units,
including chlorination. It also provides a tool for the evaluation of an
existing system to assess how well the system meets acceptable criteria.
PART II ~ OPERATION AND MAINTENANCE
This part will be particularly useful to the person responsible for
the day to day operation and maintenance of a system and for compliance
with the water quality and other legal requirements.
The Interim Primary National Drinking Water Regulations are
summarized. Separate chapters are devoted to maintenance and record,
keeping. The operator is also alerted to certain special problems and
emergencies.
4
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PART III - APPENDICES
Appendix A is a glossary of the more common terms used in water
supply practice.
Appendix B is a listing of the State regulatory agencies and EPA
Regional Offices.
Appendix C provides a listing of reference publications.
CHAPTER AND PAGE NUMBERING
The pages in the Chapters which follow are numbered consecutively but
the page number is preceded by the Chapter number. As an example, page 2-10
is page 10 of Chapter 2. Likewise, the Figures and Tables are numbered
consecutively, preceded by the Chapter number. As an example, Table 3-1 is
Table 1 of Chapter 3.
5
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PART I
PLANNING - DESIGN - DEVELOPMENT
CHAPTERS 1 through 11
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CHAPTER I
WATER MEASURING TERMS AND UNITS
English and Metric,With Conversions
INTRODUCTION
A basic knowledge of the "language" of water technicians is an essential
tool for the proper understanding of planning, design, operation, maintenance
and management of a water system. This language forms the basis for communi-
cation, both verbal and written. There follows an introduction to some of
the more common units used to measure quantity, pressure and quality, and
definitions of some of these terms. For a more extensive reference of water
system terms in alphabetized form, see the GLOSSARY, Appendix A.
ENGLISH AND METRIC UNITS
The metric system of measure has several advantages over the americanized
English system. It is in common use as the international measuring language
and the United States is committed to a gradual change-over from English to
metric. The reader will do well to become thoroughly familiar with the metric
system and to use the terms whenever possible. For this reason, both the
English and metric terms are used in the manual. In order to avoid confusion
at this stage of "going metric", the familiar American terms are used, followed
by metric terms. However, where the use of both becomes cumbersome, only the
American term is used.
The principal advantage of the metric system is the use of the uniform
decimal system wherein all units are multiples of ten, not unlike our monetary
system. In comparison, the English system is a hodgepodge of units with no
basic uniformity. As an example, there are 12 inches m one foot, 3 feet in
one yard and 5,280 feet in one mile. In the metric system there are 1,000
millimeters in a meter and 1,000 meters in a kilometer, the metric "mile".
1-1
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In the metric system, the following prefixes are used.
mega (M) means 1,000,000
deci (d) means 1/10
kilo (k) means 1,000
centi (c) means 1/100
hecto (h) means 100
milli (m) means 1/1000
deca (da) means 10
micro Qu) means 1/1,000,000
For instance, when the "meter" is preceded by "kilo", it produces
"kilometer", meaning 1000 meters.
MEASURING UNITS
Linear Measure
The basic unit of length in the metric system is the meter.
1 meter (m) = 39.37 inches = 3.25 feet.
The meter (m) is divided into larger or smaller units up and down the
scale in multiples of ten, as are all metric units.
1 meter (m) = 10 decameters (dam) = 100 centimeters (cm) =» 1000 millimeters (mm)
1000 meters = 1 kilometer (km) = 0.62 miles (English)
Mass (Weight) Measure
The metric unit for weight (more correctly the mass) is the kilogram.
1 kilogram (kg) - 1000 grams (gm) =2.2 pounds (English)
1 gram (gm) = 1000 milligrams (mg)
1000 kilograms = 1 kiloton
Volume Measure
The common metric unit of volume is the liter.
1 liter (1) = 1000 milliliters (ml) = 1.06 quarts (English)
1 milliliter is about 1 thimble full of water.
1000 liters(1) = 1 cubic meter (cu. m) = 264.2 gallons (English)
1-2
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Rate of Water Flow
The common American term for the rate of water flow is gallons per
minute (gpm), gallons per hour (gph), gallons per day (gpd) or millions
gallons per day (mgd).
In the metric system, the liter is the most appropriate volume
measure for small water systems. Since the liter is about equal to one
quart, it is more appropriate to use liters per second than liters per
minute.
One liter per second (1/sec.) = 16 gallons per minute (gpm) (approximately)
Where larger flows are involved, the metric term,cubic meters per
minute,is appropriate.
1 cubic meter per minute (cu.m/min.) = 264.2 gallons per minute (gpm)
Pressure Units
The American term for pressure is pounds per square inch (psi), the
force in pounds exerted on one square inch of surface. Two terms are in
common use m the metric system. First, there is the kilogram per square
centimeter which is nearly equivalent to one standard atmosphere or 14.7
psi and secondly, the kilopascal (kpa). One psi is equal to about 7 kpa.
In water works practice, pressure is also referred to as a "head".
Water standing in a pipe or tank exerts a head which is dependent upon the
height of the column of water. A pipe filled with water to a depth of one
foot exerts a pressure at the bottom of the pipe equivalent to 0.43 pounds
per square inch.
1 foot of water head = 0.43 psi
2.31 feet of water head = 1.0 psi
231 feet of water head = 100 psi
] -3
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Height and pressure are therefore inter-related. In a "static system",
the pressure head depends only on the height of the column of water and the
size of the pipe is immaterial. A "static system" is when no water is
flowing and the resulting pressure is called the "static pressure". The
pressures exerted in a flowing water system is called the "dynamic pressure".
Temperature
In the English system, temperature is measured in the familiar degrees
Fahrenheit (°F) on a scale where water freezes at 32° F and boils at 212° F
(at standard sea level). On the metric scale, degrees Celsius (°C), water
freezes at 0° C and boils at 100° C.
Conversion of Common Terms
There follows Table 1-1 which lists commonly used English and metric
equivalents. It is common practice to round off decimals where high accuracy
is not important. Table 1-2 is a listing of handy (approximate) conversion
factors to simplify conversions from one term to another.
1-4
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Table 1-1: English Units and Metric Equivalents
English
Metric
English
Me trie
LENGTH
AREA
1.0 inch (in.)
0.3937 inch
1.0 foot (ft.)
J.28 foot
39.37 inches
1.0 m 10-3 (mi . )
0. 62 mi lit s
2.54 centimeter (cm)
1.0 centimeter
30.48 centimeter
1.0 meter (m)
1.0 meter
1.61 kilometer (km)
1.0 kilometer
1.0 sq. inch
0.155 sq. inch
1.0 sq. feet
10.76 sq. feet
1.0 acres
2.47 acres
1.0 sq. mi.
0.386 sq. mi.
6.45 sq. centimeter (sq.cm)
1.00 sq. centimeter
0.09 sq. meter (sq.m)
1.0 sq. meter
0.405 hectare
1.0 hectare (10,000 sq. meter
259.0 hectare (259 sq.km)
1.0 sq. km (100 hectare)
VOLUME
VOLUME
1.0 cubic inch (cu.in.)
{
16.39 cu. centimeter ( cc ) j
0.06 cubic inch
1.0 cu. centinetcr(cc ) |
1.0 cubic feet
0.028 cu. meter (cu.m) |
35.31 cubic feet
1.0 cu. meter j
1.0 ounce
29.57 milliliter (ml) !
i
i
1.0 quart (qt.)
1.057 quart
1.0 gallon (gal.)
0.26 gallon
1.0 gallon
264.2 gallon
0.946 liter (1)
1.00 liter
3.79 liter
1.00 liter
0.003785 cu. meter
1.0 cu. n>eter (cu.m)
WEIGHT ( MASS)
;, RATE OF
;
i
1'LO'a'
1.0 ounce (oz.)
0.035 ounce
1.0 pound (lbs.)
2.205 pound
! 28.35 grams (gm)
1.0 gram
0.454 kilogram (kg.)
j 1.0 kilogram
!
ijl.O gal. per mi. (gpm)
264.2 gpm
,|1.0 gpm
j; 0.264 gpm
j[ 15 .85 gpm
0.003785 cu. meter/min.
1.0 cu. meter/min.
3.79 liter per min.
1.0 liter per mm.
1.0 liter per sec.
PRESSURE
PRESSURE
! I
1.0 pound/sq.inch (psi) ! 0.070 kilograms/sq.cm
14.7 psi (1 atmosphere) i 1.03 kilograms/sq.cm
' i
; 1 0.145 psi
1 psi
1.0 kpa (kilopascal)
6.9 kpa
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Table 1-2: Approximate Conversions
When you know
Multiply by
To Find
Inches (in.)
Millimeters
Inches (in.)
Centimeters
Feet (ft.)
Meters (m)
Miles tfni.)
Kilometers
25
0.04
2.5
0.4
0.3
3.3
1.6
0.6
Millimeters (mm)
Inches (in.)
Centimeters (cm)
Inches (in.)
Meters (m)
Feet (ft.)
Kilometers (km)
Miles (mi.)
Ounces (oz.)
Grams (gr.)
Pounds (lb.)
Kilograms (kg)
28
0.035
0.45
2.2
Grams (g)
Ounces (oz.)
Kilograms (kg)
Pounds (lb.)
Gallons (gal.)
Liters (1)
3.8
0.26
Liters (1)
Gallons (gal.)
Pounds per square inch (psi) 7.0
Kilopascals (kpa) 0.14
Feet of water head (ft.) 0.43
Pounds per square inch (psi) 2.3
Kilopascals (kpa)
Pounds per square inch (psi)
Pounds per square inch (psi)
Feet of water head
o
Fahrenheit temperature ( F)
,o
Celsius temperature ( C)
0.56 (after Celsius temperature ( C)
subtracting 32)
1.8 (then
add 32)
o
Fahrenheit temperature ( F)
Gallons per minute (gpm)
Gallons per minute (gpm)
60
1440
Gallons per hour (gph)
Gallons per day (gpd)
1-6
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WATER QUALITY
The term "water quality" is a generalized expression of the suitability
of water for human consumption or food processing. The contaminates in
water determine its quality. Hard waters containing calcium and magnesium
salts may be clear and free from micro-organisms, but may be objectionable
because of the high consumption of soap in washing, the formation of scums
and the scaling of boilers and hot water systems. On the other hand, an
overly soft water may be corrosive causing rapid deterioration of pipes and
appurtenances. An otherwise good quality water may contain objectionable
amounts of iron or manganese causing the staining of fixtures, laundry and
imparting taste to the water. Water may look perfectly clear but may be
contaminated with micro-organisms which renders the water unsafe for human
consumption unless properly treated.
The word "pollution" is also a general term implying the fouling of
water by sewage or other waste water, rendering it unfit for use as a water
supply.
"Contamination or contaminate" implies a specific type of pollution
whether it be particulate matter, a chemical in solution, micro-organisms,
or radioactive substances. Contaminates which cause illness, death, or
adverse physical effects to humans are called "primary contaminates" and
the National Primary Drinking Water Regulations specify the maximum allowable
concentrations or contaminate levels of these substances. These are des-
cribed in Chapter 12. Other forms of contaminates tend to render the
water aesthetically undesirable, including particulate matter^^
tionable color, taste, odor, hardness, corrosiveness, etc. These latter
contaminates are called "secondary contaminates". Chapter 12 lists many
of these secondary contaminates along with recommended limiting
(1) Turbidity
1-7
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concentrations- These secondary contaminates are not enforceable under
the Federal Act, but individual States may adopt mandatory limits for
these contaminates.
"Microbiological contamination" is the fouling of water with potential
disease producing organisms. These organisms are not visible with the
naked eye. Because it is not practical to test for all of the potential
disease organisms which might be present m a water supply, microbiolo-
gical contaminates usually refers to a group of bacteria called "coliform
bacteria". Coliform bacteria are a group of micro-organisms usually
associated with the fecal discharges of man and animals, but also
occasionally found elsewhere in nature. Their presence in water is con-
sidered evidence of serious contamination. Although these organisms are
not necessarily pathogenic (capable of causing disease) they are con-
sidered presumptive evidence of the possible presence of infectious
organisms. Their presence is a danger signal that the water is of
questionable quality and/or that the treatment process is inadequate or
that contamination has occurred.
"pH" is a measure of the hydrogen ion activity of a water solution,
or more simply a measure of whether the water will react as a mild acid or
an alkaline solution. The pH scale runs from 0 to 14. A pH of 7.0 is
neutral, neither acid nor alkaline, if the pH is less than 7.0, the
water is said to be acid, if greater than 7.0 it is alkaline. Since the
scale is logarithmic, a difference of one whole unit up or down represents
a ten fold change, that is a change from say pH 6.0 to 5.0 means that the
water is ten times more acid. pH 8.0 is ten times more alkaline than pH 7.0.
The pH of the water is influenced by the minerals or chemicals, including
gases, in solution. Carbon dioxide gas in solution tends to
1-8
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make water acid (carbonated water). Limestone minerals tend to make it
alkaline on the scale. The pH of water is important from many aspects.
It has a significant effect on water treatment processes and on the
efficiency of chlorine as a disinfectant. It is related to the corrosion
of piping and appurtenances and the deposition of mineral deposits.
While it is convenient to express pH in terms of its reaction as
acid or alkaline, the pH is not the same as "alkalinity" or "acidity".
The latter terms express the reserve or buffering capacity of water to
resist change in pH.
The pH of waters used for human consumption varies over a surprisingly
wide range, perhaps as low as 4.0 and as high as 10.0. However, the extremes
pose certain problems that can only be evaluated by a water specialist.
The pH of a sample of water can often change when exposed to air or temper-
ature changes. Therefore, sampling and testing procedures are very important.
The test is made by an electronic meter or colorimeterically using dyes which
change color depending on the pH.
(2)
"Turbidity" is a measure of the suspended matter ,in water, such as
clay, silt, finely divided organic matter, algae and other micro-organisms
when present in large numbers, it is measured by passing a beam of light
through a sample in a special tube and measuring optically the scattered
(3)
and absorbed light. The measuring scale is in turbidity units (NTU). A
turbidity of 5 or more units is readily detectable with the naked eye in a
glass of water. Turbidity is of significance because of its objectionable
appearance (cloudy water) and because it will interfere with disinfection of the wat
"Chemical units" - The chemicals present in both natural and treated
water vary greatly, reflecting the environment through which the water
passed ana the treatment processes. Many of the substances found in water
are presenr in trace amounts while others are present in comparatively laryc
(2) A measure of the clarity of water
(3) Nephe .ometric Scale (NTU) 1-9
-------
amounts. Although a variety of measuring units are used in water supply
practice, metric units are used extensively in water quality determinations.
On the other hand, water works practice still deals extensively in the
English units.
The basic measuring units, parts per million (ppm) and milligrams per
liter (mg/1) are used interchangeably, but scientifically speaking they
are not exactly the same when concentrations exceed several thousand units.
For all practical purposes, they may be used interchangeably. Mg/1 is preferred
Since water weighs 8.34 lbs. per gallon, one million gallons of
water will weigh 8.34 million pounds. Therefore for every 8.34 lbs. of
a pure chemical substance in one million gallons of water, the concentration
of that chemical will be 1 part per million. One second in 11 1/2 days
is equivalent to one part per million, so the unit is small indeed.
In a laboratory water is measured in metric units and the basic
unit is the liter. The liter contains 1000 milliliters (ml) of water.
Likewise, the gram (gr) is the basic weight measure m a water laboratory.
1000 grams = 1 kilogram
1 gram = 1000 milligrams (mg)
1 milligram = 1000 micrograms (ug)
One liter of water weighs 1000 grams. Therefore, one milligram of a pure
chemical substance in one liter of water is one part per million parts of
water or one milligram per liter (mg/1).
It is not convenient to measure trace amounts of chemicals in parts
per million or milligrams per liter as fractions or decimal numbers will
result. Therefore, the term parts per billion is often used.
1 part per billion (ppb) = 1 migrogram per liter (ug/1)
(1 second m 32 years is one ppb)
1-10
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"Microbiological Units" - Biological tests to identify the many specific
infectious organisms which may be potentially present in a natural or treated
water supply requires considerable laboratory sophistication and is time
consuming. Years ago, a relatively simple and less time consuming laboratory
procedure was developed to test for the common coliform group of bacteria.
The tests for these bacteria are highly perfected, standardized and accepted
throughout the nation.
Two basic test methods are used. The older procedure is generally called
the fermentation tube method. A series of test tubes with selective liquid
growth media are inocculated with standard volumes of test water and incu-
bated at a favorable growth temperature. The presence of coliform bacteria
is indicated by gas formation during incubation in one or more tubes. Single
tests should be interpreted with caution. However, a series of tests taken
at specified intervals over a period of time, are highly reliable indicators
of the microbiological quality of a water.
The second test method is called the membrane filter technique. A
100 ml sample of water is filtered through a special filter pad. Coliform
bacteria which may be present are strained and trapped. The pad is then
placed in a special growth media and incubated at a precise temperature.
Individual trapped coliform bacteria grow as a visible colony. By counting
the colonies, a measure of the number of coliform present in the water is
obtained. This test is relatively faster and simpler than the fermentation
tube method.
Both tests are approved for use under standardized procedures set forth
in "Standard Methods for the Examination of Water and Waste Water" published
by the American Public Health Association. However, the two methods do not
necessarily produce interchangeable counts nor can one result be translated
1-11
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to produce an equivalent count m the other method. The Primary Drinking
Water Regulations define maximum microbiological contaminate levels based
upon the use of either test, chapter 12 lists these levels.
1-12
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CHAPTER 2
PLANNING, SANITARY SURVEY AND DESIGN CONSIDERATIONS
INTRODUCTION
The public has an expectation that a public water supply will be safe
and adequate at all times and the purveyor has the responsibility of meeting
that expectation. The potential for wide spread harm from a contaminated
water system is always present. The risks will be reduced considerably by
careful planning, design, and construction. A poorly planned system
increases the potential for unsafe water, interruptions, and poor service
and complaints are likely to follow.
This chapter discusses the steps necessary for the proper design of a
new water system. These steps will also be useful when considering enlarge-
ment or expansion of an existing system. They will also be helpful in
evaluating and comparing an existing water system with accepted design and
construction standards. The steps include (1) the early planning considera-
tions which are necessary prior to the design phase, (2) the sanitary survey
of the potential water sources to determine the safety of the supply and
water treatement requirements, (3) engineering design elements of the water
system components, and (4) submission of plans to the State regulatory
agency for review and approval prior to construction of the system. Refer-
ences are made to specific chapters in the Manual for additional details.
The chapters that follow discuss the design criteria for the various
system components.
2-1
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PLANNING ELEMENTS
Prior to the design of a water system, it is prudent to consider the
present and long range objectives and the alternate ways of accomplisln nq
those objectives. Costs are of course an integral part of the process and
costs will most likely be a factor in the decision making process. However,
cost economies which significantly reduce reliability or trade-offs which
sacrifice good sanitary protection for reduced costs, are ill advised.
Since a good portion of the system will be buried in the ground, quality
materials and workmanship will avoid costly repairs or replacements in the
future.
Some of the early planning considerations are discussed below:
1. Effective planning requires both near and long range considerations.
Much of the water system will be below ground and future unanticipated
changes and enlargements will be expensive. Therefore, the planning phase
should consider future projections for growth and future increases in per
capita or other base water consumption. With these projections, decisions
can be made on how much future capacity should be built into the system
during the initial construction phase and how much should be planned for
future construction.
2. An early decision must be reached on the desirability of fire protec-
tion, as fire flows will dictate the sizing of most of the system components
in a small system. Local fire underwriters will assist in making this
decision. State laws require water for fire protection for certain types of
public places and institutions, consult local building codes for specific
requirements. Chapter 3 provides some guidelines.
3. Where there is a water system, there may be a need for waste water
disposal. The two systems must be properly separated as there is an
inter-relation between them which must be kept under continual
2-2
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control- Water lines and waste water systems operate essentially sjde by
side, but must be kept separated to avoid contamination of the water system.
Cross-connections must oe avoided (see Chapter 15) and the buried water and
sewer pipes must have proper separation (see Chapter 11). If the water
purveyor also has responsibility for the design and operation of the waste
disposal facilities, the appropriate State agency should be consulted for
detailed requirements.
4. Investigate all possibilities for a connection with an existing
approved public water system as opposed to developing a new source of water.
The existing system must have sufficient capacity to meet the additional
demands, including future qrowth. Booster pumps and reservoirs may be
necessary where pressure differences are a problem, state agencies are
usually quite receptive to the extension of approved existing systems.
Also consider the possibility of a future connection to an existing approved
system. As systems grow, it may be mutually desirable to consolidate into
a single system.
5. Determine the water quantity requirements of the system. See Chapter 3
and Table 3-1 for some guidelines. Obtain additional data based upon local
experience at similar establishments. Include all special water needs.
Determine the following:
- per capita or other unit daily needs
- Fire protection needs if appropriate
- Special needs such as lawn watering, cooling water, process water, etc.
- Project future requirements
- Determine the average daily, and maximum daily demands.
- Determine the maximum hourly and instantaneous peak demands
2-3
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6. Determine possible alternative sources of water, evaluating availability,
quantity, quality, engineering aspects, costs, etc. see Chapter 4 for
guidance.
- First, consider possible connection to an existing approved puhlu;
water system.
- Wells or springs or other grojnd water sources are good second
choices.
- Surface water sources will require special considerations and should
not be attempted without prior consultation with the State agency.
7. After evaluation of possible alternative sources, select the most appro-
priate for detailed sanitary survey, exploration and design using the water
demand criteria to determine the required capacities.
SANITARY SURVEY OF POTENTIAL WELL AND SPRING SITES
Ground waters are by far the most appropriate source of water for
small public systems. The advantages and design criteria for well water
supplies are described m some detail in Chapters 4 and 5. Spring supplies
are also used occasionally (see Chapter 7). Surface waters are a poor third
choice and should not be used if a ground water of satisfactory quality is
available, in any case, a sanitary survey of the potential sites for wells,
springs and surface sources is necessary to insure tha*- the supply can be
properly protected from contamination. The State agency will provide
"Sanitary Survey" forms to assist in identifying and recording data. In
the absence of these forms, at least the following information should be
obtained and recorded to assist in the site selection.
1. Consult well drillers, water engineers and others to determine the
best well locations in the vicinity, based upon local experience and
keeping m mind the convenience of the sites.
2. Determine the availability of the land. Sufficient land must be pur-
chased or controlled to insure protection from future adjoining land use
¦ u L iviLlCS.
2-4
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See chapter 5 for some of the controlling factors. The water purveyor
should obtain control over all land within at least 100 feet of the well.
Fencing may be advisable.
3. Determine the proximity to nearby sewers, sewage and waste disposal
facilities, animal pasturing and agricultural land which is under treatment
with agricultural chemicals. Other potential sources of contamination
should be assessed, including road salt, petroleum, and other chemical
storage areas. Record data on a site plan or a survey form.
4. Determine potential for flooding and whether within 100 year flood
level, available through the local National Flood insurance program.^
determine direction of flow of surface run-off. Prepare basic contour map
of site. USGS maps will be helpful.
5. Determine character of local geology, depth and types of soil overburden
above rock and types of rock formations. Estimate probable depth to the
ground water table. Well drilling records of nearby wells may prove helpful.
6. Determine probable characteristics of the ground water formations
(aquifers), artesian characteristics, direction of ground water movement, etc.
7. Study nearby wells to determine quality of water, casing depth, well
drawdown and yield. (See chapter 5).
8. Limestone and similar rock formations may carry pollution great dis-
tances from the source of the pollution. Extreme care is advisable in
selecting sites in these aquifers.
After compiling and evaluating the information gathered from the
sanitary survey, select the site(s) which provide the best sanitary pro-
tection and offer the best opportunity for developing an adequate source of
water. Test wells may be advisable to verify conditions. Chapter 5 offers
criteria for the construction and development of wells. For more detailed
(1) This inform.ition i«< usually available at the local government level and
jl so .it Liu- State agency designated to assist in the administration of
flood plain program.
2-5
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information, the Manual of Water Well Construction Practices, EPA-
570/9-75-001 (1976) may be obtained from the U.S. Government Printing
Office, Washington, D.C. 20402 for a nominal charge. The manual also
provides valuable information on well drilling contract documents.
SANITARY SURVEY OF POTENTIAL SURFACE WATER SUPPLIES^
A sanitary survey of potential surface water sources is necessary to
identify and assess potential sources of pollution, assess the water quality
and determine the required degree of treatment. The State regulating agency
must be consulted.
1. Determine water rights and impact of taking water from watershed.
Consult with the appropriate State or other agency involved with surface
water rights.
2. Determine the safe yield at minimum flow conditions and compare with
water use requirements.
3. Assess the character and use of upstream land in the watershed. Deter-
mine the nature and extent of all potential pollution hazards.
- Assess agricultural, forestry, and recreation practices.
- Identify and assess impact of sewage disposal systems.
- Identify and assess industrial waste, mine,oil field, and solid
waste disposal drainage.
4. Determine quality of the surface water over an extended period of time
including low and high flow conditions. Assess impact of high flood
run-off. This should include laboratory tests for turbidity, color, con-
form bacteria, algae, minerals, pH, toxic contaminates and taste and odor
producing substances.
5. Determine the most appropriate location and depth of the intake,
taking into account seasonal water level variations, wind drift, debris
accumulation, freezing and ice cover.
( 2) Also see Chapter 8
2-G
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WATER SYSTEM DESIGN ELEMENTS
After selecting the source of water (wells, springs or surface supplies)
based upon the sanitary survey assessment and other factors, ("ho desiqn phase
will follow. Listed below are the basic design elements. Chapter 3 provides
guideline criteria for the Design Capacity of System Components. The follow-
ing elements should be considered in the design.
Well Systems (See Chapters 5 and 6)
1. Select the most appropriate well site based upon the sanitary survey and
other factors. Determine amount of land necessary to provide present and
future protection and land for future wells if necessary.
2. Determine most appropriate well design features including: Type of
well, drilling techniques, size and depth of casing, grouting requirements,
well cap arrangement, screens if necessary, and other features. Keep an
accurate log of the drilling process.
3. Develop the well, determine the drawdown at various yields and select
the optimum yield (Chapter 5).
4. Compare the well yield with water demand requirements (Chapter 6) and
determine the number of wells required to meet the demand. At least two
wells are recommended to insure continuity of service if one well becomes
inoperative.
5. Sample and test the water to determine the chemical, physical and
bacteriological quality of the water. Determine the required treatment,
if any. Consider chlorine disinfection as an added safety factor even if
the State agency does not require it.
6. Determine the well pump details based upon the well yield and the system
water demands and pressure requirements. Determine whether gravity storage
or pressure pneumatic storage system is most appropriate (see Chapter 6).
Consult with t"he electric company for electric service, line voltages,
phasing, etc.
2-7
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"7. Design pumphouse, where applicable. Include adequate space for pres-
sure storage tanks, treatment and conditioning equipment, electrical
controls, sanitary protection, protection from freezing, ease of mainten-
ance, floor drains, etc.
Spring Supply Systems (Chapter 7)
1. If the sanitary survey of the spring site proves satisfactory, deter-
mine the amount of land necessary to insure present and future protection.
Fencing should be considered as should drainage diversion where necessary.
2. Determine the spring yield, including effect of seasonal and annual
variations in the yield. If the yield is adequate to meet water demands,
design the spring collection chamber to provide adequate protection and to
capture as much of the yield as possible. Design the spring storage tank
as part of the collection chamber or as a separate structure. Provide at
least one days storage based on the average daily demand.
3. Sample and test the quality of the water as in Item 5 under well
Systems and determine the required treatment if any.
Surface water Systems Including Infiltration Galleries {Chapter 8)
1. If the sanitary survey and other factors are satisfactory,determine
the safe yield and the need for impoundments if any. Compare the safe
yield with water demand requirements.
2. Obtain the necessary water rights and establish the measures necessary
to protect the watershed from contamination.
3. Sample and test the quality of the water as in Item 5 under Well
Systems. Determine the required treatment.
4. Design the impoundment (if needed) and the intake structure, consult
with the appropriate authorities before constructing a dam.
2-8
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5. Design the treatment units. Continuous chlorination will be required
as well as other treatment, depending upon the quality of the surface
water.
6. Design the gravity storage or hydropneumatic system (Chapter 6}.
Distribution System and Building Piping (Chapter 11)
1. Determine the water demands in the various parts of the system
including pressure requirements.
2. Design the distribution system including type of pipes, sizes,
valving and other appurtenances taking into account the above Item 1.
3. Design the various building or water use area piping systems.
Submitting Plans To The State Agency
1. Consult with the State agency early in the planning phase, obtain
special design criteria, applications, procedures, etc.
2. Submit preliminary engineering report for early review and comment.
Submit required applications.
3. Submit detailed plans and specifications for approval, include dis-
infection procedures for wells, springs, tanks, pumps, piping and
appurtenances. Disinfection procedures are discussed in chapters 5, 6,
7. 8 and 11 for wells, well pump systems, springs, surface water supplies
and the distribution system, respectively.
During Construction
1. Construction should be in general conformance with plans and specifi-
cations. Significant deviations must have prior approval of the State
agency.
2. Prepare "as built" plans for future reference, underground facilities
should be clearly referenced in relation to permanent landmarks, curbs,
buildings, sidewalks, etc.
2-9
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3. Disinfect all parts of the system. Advise the State agency of (he
time of disinfection as they may wish to observe the procedures. Do
not use any part of the system until samples have been collected and
tested for coliform bacteria to verify the adequacy of disinfection and
treatment.
4) Establish procedures for:
- Operation and Maintenance - chapter 13
- Sampling, Testing and Reporting - chapter 13
- Record Keeping and Reporting - Chapter 14
2-10
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CHAPTER 3
DESIGN
CAPACITY OF
Water Demands - Design Capacity of Well, Spring and
SYSTEM
COMPONENTS
Surface water Systems - Storage - Distribution
Systems and Building Piping
INTRODUCTION
A key factor in the planning and design of a water system is an
accurate estimate of the quantities of water which must be supplied to
meet water needs. These estimates are pivotal to the entire design
including the production of water, pumping, treatment, storage, and the
distribution system. Each water system component is designed to meet
certain water flow requirements, all designed to insure that water will
be available at the various water use points throughout the system in
adequate quantities to meet demands. Over design may result in increased
initial costs but under design will result in inadequate service and poten-
tial health hazards, and increased costs to correct the condition. On the
whole, it is better to design for the high side of water demands than to
under design.
The purpose of this Chapter is to provide guidance in estimating
water demands and to provide an overall perspective for the design criteria
of the various system components, based upon these estimates. The design
of system components are also more fully developed in the chapters that
follow, as referenced.
insofar as possible, guidelines which have broad acceptance throughout
the nation are presented. However, the great variety of small water supply
types makes it impractical to include a full range of water consumption and
water demand data, even if complete reliable data were available, which is
not the case. Water consumption varies quite significantly throughout the
3-1
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country depending upon the use of water meters, economic conditions, Iempera-
ture, precipitation and lawn watering practices, fire protection requirements
and other factors. Therefore it will be prudent to seek local experience
and requirements with similar types and sizes of water systems and to u^e
that information in making final judgments. The State regulating agency is a
good source of information on water demands and local requirement1--, and should
be consulted early in the design.
ESTIMATING BASIC WATER DEMANDS
The various components of a water system are designed to meet specific
wacer flow criteria which are dependent upon the type of water system and the
objectives of the system. Some of the more useful terms follow:
Average Daily Demand
The average daily demand is a term used to express the quantity of water
used in a system in an average day. It is based upon experience from water
meter readings in similar water systems over an extended period of time and
reflects the normal seasonal and daily variations. For design purposes, it
Ls usually determined by estimating the population or units of housing or
other units and multiplying by an average per person or per unit water con-
sumption derived from past experience. Other water demand terms frequently
relate to this basic term. The average daily demand will be exceeded on
many days so it is not appropriate to design merely for the average. For
this reason other terms are used to express the probable greatest amount of
water which may be used in one day, or other period of time.
Table 3-1 provides a guide for estimating the average daily demand for
various types of establishments, in gallons per day per unit. The unit is
persons per day unless otherwise indicated. The values shown may vary
throughout the nation and the reader is advised to review local information
on water systems serving similar size establishments. The State agency will
provide additional guidance.
Note: Metric and English Conversions
1 gallon = 0.003785 cubic meters = 3.79 liters
1 cubic meter (1000 liters) = 264.2 gallons
3-2
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Table 3-1:
Guide for Estimating Average Daily Water Requirements
(Adapted from various sources for small water systems)
Average
Type of Establishment
Daily
(The unit is per person unless
Use
otherwise stated)
(gpd)
Airport (per passenger)
3-5
Assembly Halls (per seat)
2
Camps - Children, overnite, central facilities
40-50
- Construction
50
- Migrant Labor
35-50
- Day type, no meals served
15
Churches (per member)
1
Cottages, season occupancy
50
Clubs - Residential
100
- Non residential
25
Factories, sanitary uses, per shift
15-35
Food Service - Restaurants
7-10
- With bars
9-12
- Fast food
2
Highway Rest Areas
5
Hotels (2 persons per room)
60
Institutions - Hospitals (per bed)
250-400
- Nursing Homes (per bed)
150-200
- Others
75-125
Office Buildings
15-30
Laundries, self service (per customer)
50
Motels (per bed)
60
Parks - Day use (with flush toilets)
5
- Mobile Homes (per unit)
200
- Travel trailers (per unit)
90-100
Picnic Areas (with flush toilets)
5-10
Residential Communities
- Multi-family (per bedroom)
120
- Rooming house and tourist homes
type (per bedroom)
120
- Single family type (per house)
400
Resort Motels and Hotels
75-100
Retail Stores (per toilet room)
400
3-3
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Table 3-1: (Continued)
Average
Type of E3tablisiment
Daily
(The unit is per person unless
Use
otherwise stated)
(gpd)
Schools - Day, no showers or cafeteria
15
- Day, with cafeteria
20
- Day, with showers and cafeteria
25
- Residential types
75-100
Shopping Centers, per sq. ft. sales area
0.15
Swimming Pools and Beaches
10
Theaters - Drive-in (per car)
3-5
- Others (per seat)
3
Note: The values listed in Table 3-1 are for normal water requirements and
do not include special needs or unusual conditions. Additional
allowance should be made for frequent lawn watering, swimming pool
maintenance, industrial or commercial process water, cooling water,
fire fighting and other special uses.
3-4
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Maximum Daily Demand
The maximum daily demand is the greatest amount of water that a bys-lem
will use in one day. Experience with small residential water systems suggests
that the maximum day is 1.5 to 2 times the average day. However, thib ratio
may not apply to other types of water systems. In general, the smaller the
water system, the greater the variation between the average and the maximum day.
Maximum Hourly Demand
The maximum hourly demand is the greatest amount of water which will be
used in any hour during a day. It is sometimes referred to as the peak hour
demand although there will be short term peak demand rates lasting for several
minutes which will exceed the maximum hourly demand rate. Each type of system
exhibits its own maximum hourly and short term peak demands and the hours of
peak occurrence will vary. As an example, shopping centers usually experience
hourly peaks in the early afternoon while residential communities may experience
two peak hours, about 8:00 a.m. and 6:00 p.m. The maximum hourly demand is
often expressed as a ratio of the average daily demand, in gallons per minute/1
Generally speaking, the smaller the system, the greater the maximum hour rate
in respect to the average daily rate.
Peak Demand
The peak (instantaneous) demand is the maximum amount of water necessary
to meet the peak short term demand rate which may occur several times during
a day, but usually during the peak hour period. The instantaneous peak
may last for several minutes. The rate is particularly important in con-
sidering the sizing of the storage tank in a hydropneumatic system (See
Chapter 6, Section on Hydropneumatic Systems). The effective storage capacity
is usually designed to meet these short term peaks. In the absence of
sufficient effective storage to meet extended peak demands, the wells and
pumps must be capable of meeting the peak demands. The smaller the system,
the greater the ratio of the peak demand to the average demand.
(1) Experience with small residential communities suggests that the peak
hourly demand may range from about 6 to over 10 times the average daily
demand.
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Estimating Peak Demand Based Upon Water Fixture Values
The peak demand load of a system is best determined by actual experience
with similar systems of comparable size. Even so, considerable judgment must
be used in applying the data to another system. If comparable data is not
available, the fixture demand method may be used. The most common methods
are based on the method described in the Plumbing Manual Report BMS-66 published
by the National Bureau of Standards. The American Water Works Association has
modified this method to provide an adjustment to reflect the effect of
delivery pressure on the demand load of fixtures. This method is presented
below with the permission of the American Water Works Association. The full
text may be found in the AWWA Manual M22, Sizing Water Service Lines and
Meters, 6666 Quincy Avenue, Denver, Colorado, 80235.
The fixture demand method of estimating the peak water demand includes a
listing of commonly used water fixtures for which a fixture value has been
assigned which reflects its demand producing effects, See Table 3-2. The
total number of each type of fixture to be used is determined and this total
is multiplied by the assigned value of the fixture. The various fixture
value totals are then summed up to obtain the combined value of all fixtures.
This combined value is applied to a graph (Figure 3-1 or 3-2) and the probable
system demand in gallons per minute is determined. An adjustment may be made
for the delivery pressure (Table 3-3) and the adjusted peak demand is thus
determined.
The fixture values listed in Table 3-2 represent the flow demand of each
fixture when operated with no other fixture in use and at a delivery pressure
of 35 psi. As an example, a bathtub is assigned a fixture value of 8 because
it will normally deliver 8 gpm at a delivery pressure of 35 psi. If a desired
fixture is not listed, an estimate of its fixture value may be obtained by
treasuring its delivery rate at 35 psi.
3-6
-------
The curves shown in Figures 3-1 and 3-2 compensate for the probability
that as the number of fixtures increase, the relative number of fixtures whu-li
will be operating at one time will diminish. Figure 3-1 is bet>t used for low
range combined fixture values which add up to 1300 or less while Figure 3-2
may be used for combined fixtures values up to 13,000.
The fixture values shown in Table 3-2 are based upon a water delivery
pressure of 35 psi. Table 3-3 lists the multiplication factors used to adjust
the demand load obtained from Figure 3-1 or 3-2 for various other delivery
pressures.
3-7
-------
Table 3-2: Plumbing Fixture Vali
Fixture Value
Based on 35 psi
Fixture Type Operating Pressure
Bathtub 8
Bedpan washers..... 10
Combination sink and tray 3
Dental unit 1
Dental lavatory . . . 2
Drinking fountain (cooler) l
Drinking fountain (public) 2
Kitchen sink: 1/2-in. connection 3
3/4-in. connection 7
Lavatory: 3/8-in. connection 2
1/2-in. connection 4
Laundry tray: 1/2-in. connection 3
3/4-in. connection 7
Shower head (shower only) 4
Service sink: 1/2-in. connection 3
3/4-in. connection 7
Urinal: Pedestal flush valve 35
Wall or stall 12
Trough (2-ft. unit) 2
Wash sink (each set of faucets)... 4
Water closet: Flush valve 35
Tank type 3
Dishwasher: o/2-in. connection... 4
3/4-in. connection 10
Washing machine: 1/2-in. connection 5
3/4-in. connection 1?
1-in. connection •. 25
Hose connections (wash down): 1/2-in 6
3/4-in 10
Hose (50-ft. length-wash down): 1/2-in 6
5/8-in ¦ ¦ ¦ 9
3/4-in 12
Table 3-3: Multiplication Factors to Adjust. Dc-Pxand Load to Various Wat?^
Delivery Pressures
Desigr Pressure
psi
Factor
20
0.74
30
0.92
35 Base
O
O
40
1.07
50
1.22
60
3-
co
70
1.46
80
1.57
90
CP
CD
100
1.78
3-8
-------
Donwiiic Itaf
B««d on Ji ou 11 Mtwf
Drtcnttpr lo* M
HoUH
Snoop«nQC«nr«fi
RtttM'mn
Sciioe't
Puiilif BiaUil^
HoHkM
Aptnnwnti
Moi«t»
Condcwmntwfl)*
Ti«.l«r P*At
Oomm* Utt Only
No IrfiaMton
500 GOO 7dO 000
Combined Fiilgrc Vitut
Fig. 3-1 Water-Flow Demand per Fixture Value-Low Range
Bned on 35 pu «t Mfttr
Docterge tor HroTwr
Doffwt< Uw
Suburb
Moira
Shooo-n? Ctnttn
AmiamwU
Pij&J»c SrftooH-SuikljAp
Motpil«U
Apirimtnti
C orwtoffi tniurat
MotcU
T(«^ I rtJfl
Fig Water-Flow Demand per Fixture Value-High Range
Table 3-2 and 3-3 and the above graphs are reprinted by permission of the
American Water Works Association from Manual M-22, Copyrighted 1975, 6666
West Quincy Avenue, Denver, Colorado, 80235.
3-9
-------
An example showing the method of using the tables and curves follows:
Example: Assume a 40 unit motel with a small coffee shop and small
swimming pool. Water pressure assumed at 40 psi. Air conditioners
are air cooled and require no water.
DATA TABULATION
Fixture Value
No
. of
Total
at 35 psi
F ixtures
F ixture
T ixture
(Table 3-2)
in
Use
Value
Water closets, tank
3
47
141
Urinals, wall
12
2
24
Lavatory: 3/8-in. connection
2
40
80
Lavatory: 1/2-in. connection
4
4
16
Bathtubs
8
40
320
Drinking Fountains
2
1
2
Kitchen sink, 3/4-in.
7
1
7
Dishwasher, 3/4-in.
10
1
10
Wash sink
4
1
4
Hose, 50 ft., 5/8-in.
9
3
27
Swimming pool
15 (estimated)
1
15
Service sink: 1/2-in.
3
1
3
649
Combined Fixture Value - 641
From Figure 3-1, probably peak demand based on 35 psi = 55 gpm
From Table 3-3, adjusted multiplication factor for 40 psi delivery pressure = I.
Adjusted (probably) peak demand = 55 x 1.07 = 59 gpm
Demand loads for lawn sprinkling systems or other special uses must be
added as appropriate.
Peak Demand for Residential Communities and Mobile Home Parks
Figures 3-3 and 3-4, which follow, are curves developed from experience
showing the instantaneous (peak) demands for various sizes of typical resi-
dential communities and mobile home parks.
3-10
-------
FIGURE 3 "3
INSTANTANEOUS DEMAND FOR RESIDENTIAL COMMUNITY WATER SYSTEMS
(Number of Connections vs Gallons Per Minute)
Number of Connections
Source: Standards and Criteria for Design and Construction of Public Water
Supply Systems to Serve Residential Conununities:Division of Health
Services - Sanitary Eng. Section, State of North Carolina, 1974
-------
FIGURE 3-4-
PEAK DEMAND FOR MOBILE HOME PARK WATER SYSTEMS
(Number of Connections vs Gallons Per Minute)
1000
500
300
250
200
; iso
D
C
S
I
b
fU
! 80
r-<
<3
C 60
40
30
25
20
15
it:u
Number of Connections
Source.Standards and Criteria for Oesign and Construction of Public Water
^untPv Svstems to Serve Residential Communities;Divsion of Heaitn
Services-Sanitary Engineering Section. State Of North Carolina, W*
3-12
-------
Fire Flow
Fire flow is the amount of water capacity which must be designed into
a water system for fire fighting purposes. Fire flow is not included in
the definition of average daily and maximum daily demands and must be added
if fire protection is desired. Tire flows are usually expressed as gallons
per minute to fight a fire of a certain duration. Local fire underwriters
will provide specific requirements on request.
Water Meters
Experience has proven the value of master water meters and consumer
water meters (where appropriate) for monitoring water use and demands,
assessing leakage and as a means of encouraging thrift and reducing waste.
Meters should be considered where appropriate, especially where the water
is available in limited quantities.
3-11
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ESTIMATING THE REQUIRED CAPACITY OF WELLS (Refer to Chapters 5 and 6 for
design details)
It is recommended that there be a minimum of two wells with sufficient
capacity in each well to insure continuity of service if one well is out of
service, wells should not be designed for pumping in excess of safe yields.
Wells With Gravity Storage and Distribution
Wells pumped to a gravity storage system with a capacity of at least
one average day storage are designed on the basis of the maximum daily
demand or greater. With the largest well out of service, the other(s) must
be capable of meeting the average daily demand. Furthermore, it is unde-
sirable to pump wells for a full 24 hour period without an opportunity for
the wells to recover. Also the water demand is seldom exerted evenly over
a full 24 hour day. Factories for instance may use essentially the full
demand in an 8 hour shift. Residential systems exert essentially all of
the demand in 16-18 hours. Allowances should be made for this factor.
Wells With Hydropneumatic Systems
Since pressure tank systems have limited effective storage capacity,
only barely enough to meet short term instantaneous peaks, the wells and
pumps must be capable of meeting maximum hourly demands and in addition,
the longer peak demands which cannot be met with the pressure tank storage.
Some small systems serving facilities such as highway food service or rest
areas, and the end of factory shifts, may experience peaks of rather long
duration which cannot be met by theilimited effective storage in a pres-
sure tank. These will require special consideration (second well cut-in)
to meet needs. If the effective capacity of a storage tank cannot be
counted upon to supplement the pump capacity to meet extended peak demands,
the wells and pumps must be designed to meet the prevailing peak conditions.
3-lu
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Fire Protection
An extra allowance must be added if fire flow protection is desired.
In gravity systems, this allowance is added to the storage reservoir and
distribution system design, with hydropneumatic systems, it must be
added directly to well(s) and pump capacity.
ESTIMATING THE REQUIRED CAPACITY OF SURFACE SUPPLIES
(Refer to Chapter 8 for design details)
Surface water supplies generally produce water of varying and question-
able quality and are often difficult to protect. Furthermore, the required
treatment is usually more complex and costly. State authorities must be
consulted before undertaking a surface water source.
Stream run-off or flow is usually severely affected by varying rain
and snow fall and the seasons of the year. If no impoundment is available,
the minimum stream flow which may be experienced is the maximum safe yield,
assuming that the water purveyor has the legal authority to remove all
available water. If this safe yield is equal to at least the maximum day
needs, an impoundment (reservoir) may not be needed. Otherwise, it will
be necessary to provide an impoundment by damming the stream. Unless the
amount of water to be withdrawn is small in comparison to the size of the
impoundment and stream flows, a detailed analysis is necessary to determine
the necessary impoundment capacity and an experienced engineer should be
consulted. The appropriate State agency must be consulted before damming
a stream.
If pumps are used to draw water from the source, the pumps must be
capable of meeting the maximum day demands. Two pumps are recommended.
With the larger pump out of service, the second pump should meet at least
average day conditions. Gravity storage reservoirs are designed for at
least one day storage at the average daily demand.
3-15
-------
If a pressure tank system is to be used, the pun^s must meet at least
the maximum hourly conditions and in addition, the extended peak demand
which cannot be met by the effective storage capacity in the pressure tank.
Infiltration galleries constructed along stream or lake shores will
exhibit a safe yield similar to a well and the required capacity is
similar to that of well design.
ESTIMATING REQUIRED CAPACITY OF SPRINGS (See Chapter 7 for design details)
The yield of a spring varies somewhat during seasons but much less so
than surface streams. The safe yield must be determined before development.
Unless information on the yield is available for extended periods, the safe
yield should be estimated conservatively to compensate for reduced flows
during dry periods. Springs may "dry up" during extended dry spells.
Observation or experience over Long periods is advisable.
Since the flow of springs is more or less constant over a 24 hour
period, the average daily yield should be at least equal to the maximum
day demand of the system. The spring collection chamber or separate
storage tanks (if used) should have an effective capacity equal to at least
the average daily demand.
SYSTEM PRESSURES
Minimum pressures in the distribution systems and at service connec-
tions should not be less than 20 psi during peak flow periods. Minimum
working pressure should be 35 psi, but preferrably from 40 to 60 psi.
Pressures should generally not exceed 100 psi. Pressure reducing valves
may be used where necessary.
SIZING TREATMENT UNITS
Treatment units which must treat the entire water demand are sized
to meet the prevailing flow conditions at the point of treatment. In
hydropneumatic systems, they must be designed to meet the pump capacities.
3-16
-------
When treatment units precede gravity reservoirs, they are usually designed
for the maximum daily demand. Water conditioners which treat only part of
the water (such as softeners) are designed specifically for the portion of
water to be conditioned.
SIZING OF DISTRIBUTION SYSTEM
Storage reservoirs generally float on the system and are served by a
single inlet and outlet but may have separate inlet and outlet. The out-
let must be sized to meet the peak demand in smaller systems. If fire
protection is provided, the pipe is sized to meet the maximum hourly
demand or the coincident draft (maximum day plus fire flow) whichever is
greater.
The distribution pipes are usually designed for the peak demands
experienced by that portion of the system supplied by the pipe(s), except
where it also serves as a fire system, in that case, the pipes are
designed for the coincident draft (maximum day plus fire flow). An extra
allowance must be made for any continuous special demands (lawn watering,
etc.) tributary to the pipe(s).
SIZING OF BUILDING PIPES
These pipes are sized to meet the peak load required to serve indivi-
dual or combinations of fixtures tributary to each pipe plus special uses
such as air conditioners, lawn sprinklers, etc. Consult State or local
plumbing codes for local requirements on building pipe sizing.
3-17
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CHAPTER 4
SOURCES OF WATER
Ground waters - Surface Waters
INTRODUCTION
The two principal sources of water supplies are surface waters and
underground waters. Both originate from rain and snow. Some of the
precipitation collects on the surface of the earth to form the streams,
lakes and other surface waters. Some seeps downward through the earth
where it accumulates in the pore spaces in the soils which overlay the
rock formations. The seepage continues downward and laterally to fill the
interconnecting joints, cracks, solution channels, pore spaces and other
openings in the rock formations below. The ground water is not static
and tends to move slowly through the substrata, some of it reappearing at
the edge of streams and lakes or as springs and seepage areas. Energy
from the sun evaporates water from the earth, streams, lakes and seas and
promotes transpiration of moisture from growing plants to form water
vapor in the atmosphere. Water vapor forms into clouds which in
turn produces rain and snow to replenish the surface and ground
waters. This continuous process is called the water cycle.
Ground waters are by far the most important source of water for
small water supply systems, unlike surface waters, water stored in
underground reservoirs generally has a more consistent good quality, having
undergone considerable natural purification through straining and pro-
longed storage. Furthermore, ground waters are readily available in most
areas of the country in sufficient quantities to meet the needs of small
water systems. Ground waters generally require little (if any) treatment
4-1
-------
prior to use, whereas surface waters invariably require rather sophisti-
cated treatment. Therefore ground water is the preferred source unless
some unusual circumstances show that a surface supply is preferrable in a
particular case. Springs are ground waters which outcrop at the ground
surface and are often satisfactory sources of water supply when properly
developed.
This chapter discusses the nature of ground water and surface water and
is followed by chapters on the construction and development of well, spring
and surface water supplies.
GROUND WATER-BEARING FORMATIONS
There are two basic types of ground water-bearing formations, collec-
tively known as aquifers: (1) unconsolidated deposits of soil including
sand, gravel, silt and clay, and (2) consolidated formations of rock.
Unconsolidated Formations
Soils overlay much of the earth's rock crust at varying depths from
no cover to several hundreds of feet. The soils were deposited through
glacial action, alluvial outwashes and deposition in streams, lakes and
seas. Soils are classified according to grain size ranging from coarse
gravel, sand, silt and clay. Since the origin of soils varied in
time (as did the transporting water conditions), deposits generally in-
clude alternating layers of material of varying size and grading. Sands
and gravels with generous pore spaces between particles are by far the
most important water bearing soils particularly where uniform sorted
deposits occur in areas with good water recharge. On the other hand,
mixed soils containing silts and clays are generally quite impervious to
the movement of water and are poor aquifers- Silts and clays play an
important role in confining the movement of ground waters and in pro-
tecting ground waters from contamination.
4-2
-------
Consolidated Formations
The rocks that form the crust of the earth are divided into 3 classes:
Igneous rocks are derived from the hot magma deep in the earth and includes
granite, basalt and associated fragmental volcanic materials, sedimentary
rocks are formed by the deposition of minerals and rock fragments by water,
ice or wind with subsequent compression into hardened material. Deposits
of gravel, sand, silt and clay harden into rock conglomerate, sandstone,
siltstone and shale, respectively. Limestone, gypsum and salt are also
included. Metamorphic rocks are derived from both igneous and sedimentary
rocks through great alterations of heat and pressure at great depths. They
include gneiss, schist, quartzite, slate and marble.
Below a certain level in the ground, all interconnecting pores and
openings in the soil and the underlying rock are filled with water. This
level is called the "water table" and the soil and rock below it is called
the zone of saturation. Although the pores, spaces and openings are usually
individually small, collectively the total amount of water stored in the
aquifers is large. The most productive aquifers are deposits of clean,
coarse sand and gravel; coarse, porous sandstones; cavernous limestones;
and broken lava rock. Some limestones, however, are very dense and unpro-
ductive. Most of the igneous and metamorphic rocks are hard, dense, and
of low permeability. They generally yield small quantities of water.
Among the most unproductive formations are the silts atnd cla^s. The
openings in these materials are too small to yield water, and the forma-
tions are structurally too incoherent to maintain large opening under
pressure.
If the upper surface of the ground water table is free to rise and
Call with seasonal changes in rerharqe and the water is not confined and
is (free to flow, the water surface will slope more or less in the dj rci.i.xon
4-3
-------
of the overall prevailing ground surface direction. A well sunk into this
aquifer is called a water table well, if the water bearing stratum dips
beneath an impervious layer, the water flow becomes confined under pres-
sure as in a pipe. When that aquifer is tapped by a well, the water will
rise in the well casing. This is called an artesian aquifer. If the water
rises in the well casing so that it overflows, it is called a flowing
artesian well. (See Figure 4-1)
The proper "development of a ground water source requires careful
consideration of the hydrological and geological conditions of the area.
In order to take full advantage of the best possible available information
and knowledge, it is advisable to seek the assistance of a qualified ground
water engineer, ground water geologist, hydrologist, or contractor familiar
with the construction of wells in the area. It is advisable to rely on
facts and experience, rather than instinct or intuition. Facts on the
geology and hydrology of an area are often available in publications of the
U.S. Geological Survey or counterpart state agencies.
Sanitary Quality
When water seeps downward through overlying material to the water
table, particles in suspension (including micro-organisms) may be removed.
The extent of removal depends on the thickness and character of the over-
lying material. Clay soils provide effective natural protection of ground
water. Silt and sand also provide good filtration, if fine enough, and in
thick enough layers. The bacterial quality of the water also improves
during storage in the aquifer because storage conditions are usually unfa-
vorable for bacterial survival. Nevertheless, clarity alone does not
guarantee that ground water is safe to drink as this can only be deter-
mined by laboratory testing.
4-4
-------
Clouds
I
> . PRECIPITATION
wmmm&K 1
INFILTRATION [yK, Runoff
Artesian spring
Perched Water Table
Fault i-.
V -M
^N^Gravif^Spring ARTESIAN PRESSURE SURFACE
1
Water Tablei
Lake
Runoff
3 Infiltration Gallery;
Water-Table
C-WATER TABLE (UNCONFINED) AQUIFER ?! t-t. —
wi II n 1
^onf lowing ; . ^ , Water
^Artesian Veil' **Oi* -
Ocean
rlowing
Artesian Well
Table
CONFINING * LAYER1
M
ft
ARTESIAN
i (CONFINED) ; 'ACtUlFER
IMPERMEABLE' ROCK
FIGURE 4-1; GROUND WATER AQUIFERS
V-?
-------
Gr'oun'd' wa'ter- protected by deep layers 'of unconsolidated soils is more
likely to be safe than water coming from rock formations
which have shallow overburdens of soil. Where limited filtration is pro-
vided by overlying earth materials, water of better sanitary quality can
sometimes be obtained by drilling deeper. It should be recognized, lowever,
that it is not always possible to find more and better water at greater
depths because of the local geology.
In areas without central sewerage systems, sewage disposal is by means
of subsurface methods including cesspools, septic tanks and leaching systems
and occasionally by pit privies, inherently, these systems contribute
sewage pollution to the ground waters. Bacteria in the liquid effluents
may enter shallow aquifers. Sewage effluents may also reach the water-bearing
formations by way of abandoned wells or openings in rock formations.
The threat of contamination may be reduced by proper well construction, and
by locating it farther from the source of contamination. The direction of
ground water flow often approximates (but not always) that of the prevailing
overall surface flow. It is always desirable to locate a well so that the
normal movement of ground water flow carries the contaminant away from the
well. Chapter 5 provides additional criteria for proper well location.
Chemical and Physical Quality
The mineral content of ground water reflects its movement through the
minerals which make up the earth's crust. Generally, ground water in arid
regions is harder and more mineralized than water in regions of high annual
rainfall. Also, deeper aquifers are more likely to contain higher concen-
trations of minerals in solution because the water lias had more time
(perhaps millions of years) to dissolve the mineral rocks. For most ground
water regions there is a depth below which salty water, or brine, is almost-
certain to be found. This depth varies from one region to another.
4-r,
-------
Some substances found naturally in ground water, while not necessarily
harmful, may impart a disagreeable taste or undesirable property to the
water. Magnesium sulfate (Epson salt), sodium sulfate (Glauber's salt),
and sodium chloride^^ (common table salt) are but a few of these. Iron
and manganese are also often found in ground water. It is interesting to
note that regular users of waters containing significant amounts of these
substances, commonly become accustomed to the water and consider it to
have acceptable taste!
Concentrations of chlorides and nitrates in amounts higher than normal
for a particular region may be indicators of sewage pollution. This is
another reason why a chemical analysis of the water should be made periodi-
cally and the results interpreted by someone familiar with the area.
Temperature
The temperature of ground water remains nearly constant throughout the
year, water from very shallow sources (less than 50 feet deep) may vary
somewhat from one season to another, but water from deeper zones remains
quite constant, its temperature ranging close to that for the average annual
temperature at the surface.. This is why water from a well may seem to be
warm in winter or cold during the summer.
Contrary to popular- opinion, colder water is not obtained by drilling
deeper. Beyond about 100 feet of depth, the tempera.ture of ground water
increases steadily at the rate of about 1°F for each 75 to 150 feet of
(2)
dept.n . In volcanic regions this rate of increase may be much greater.
(1) Sodium salts in excess of 20 mg per liter may be harmful to people
restricted to low sodium diets. See Chapter 12.
(2) 1°C for each 42 to 84 meters.
4-7
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Developing Ground Water Sources
Wells. The most common method of developmq qround water sources is
by sinking a pipe casing into the desired ground water aquifer and icntovrnq
the water by means of suitable pumping equipment. chapter 5 covers Lhe pro-
cedures and techniques.
Springs. When ground waters issue at the surface of the ground from
the water bearing soils or rock formations, they are called springs. These
waters are often suitable for small public systems where properly developed.
Chapter 7 discusses spring development.
SURFACE WATERS
Surface waters are used extensively as sources of water for large
public systems. However, because surface waters are exposed to potentially
severe contamination by both man and nature and because the quality varies
considerably, a high degree of treatment is required to insure its constant
safety. Generally speaking, small water systems cannot provide the high
degree of treatment and supervision required, except at considerable expense.
Therefore, surface supplies should not be considered as sources if good
ground water sources are available. Chapter 8 discusses the development of
surface water supplies.
4-8
-------
CHAPTER 5
WELL CONSTRUCTION AND DEVELOPMENT(^
Site Selection - Types of Wells -
Construction - Development - Sanitary
Protection - Disinfection
INTRODUCTION
In order to reach the ground waters underlying the earths' surface, it
is necessary to construct a well vertically downward to penetrate the desired
water bearing strata. These structures may be dug, driven, bored, jetted
or drilled, depending upon the geological formations through which they must
pass and the depth to which they must reach. Dug, driven, bored and jetted
wells are usually confined to relatively soft soils overlaying rock and to
shallow depths normally less than 50 feet (15 meters). Drilled wells may
be used in both soft and hard soil and in rock and may be sunk to depths
measuring several hundred feet.
Wells are usually classed into two broad categories, depending upon
whether the ground water aquifer is under a hydrostatic head or not. These
are called nonartesian (water table) and artesian wells.
Nonartesian (water table) wells are those that penetrate the upper
ground water formations where the water is not confined by an overlying
impermeable formation. Pumping the well lowers the water table in the
vicinity of the well and water moves through the soil toward the well under
the pressure differences thus created.
(1) Some of this Chapter is adapted from the Manual of Individual Water
Supply Systems, EPA and the Manual of Water Well Construction
Practices, EPA.
5-1
-------
Artesian wells are those that penetrate aquifers in which the ground
water is found under hydrostatic pressure, confined beneath an impermeable
layer of material. Since the water is under pressure, it will rise in a
well casing penetrating the aquifer. If the pressure is great enough to
force the water to the ground level, it is called a flowing artesian well.
The intake areas (recharge areas) of confined aquifers are commonly found
at higher elevations of surface outcrops of the formations.
WELL SITE SELECTION
The selection of the well site is influenced by the ground water
aquifer to be developed, depth to the aquifer and the geological character
of formations to be penetrated. Other factors include: freedom from
flooding and surface drainage; the relation to existing or potential
sources of contamination; the quantity and quality of the water; the con-
venience of the location m relation to the service area; and the avail-
ability of sufficient surrounding land to insure protection from incom-
patible adjacent land uses. Also see Chapter 2.
The State regulatory agency should be consulted for local requirements
concerning well location, particularly the minimum protective distances
between the well and sources of existing or potential pollution. Table 5-1
is an example of typical minimum distances. It must be stressed that these
minimum distances are based upon general experience and are not guarantees
of freedom from contamination. The water purveyor should provide even
greater protection where possible. There is no substitute for a detailed
sanitary survey of the proposed site (see Chapter 2). The Table applies
to properly constructed wells with protective casing set to a depth of at
least 20 feet (6 meters) below ground surface. Other types of wells will
require special considerations.
5-2
-------
Table 5-1; Minimum Distances Between Well and Sources of Potential Pollution
Source of Pollution
Wells Cased to Depth of
20 ft. (6 Meters) or more
Remarks
Feet
Meters
Water-tight Sewers
Other Sewers
Septic Tanks
Sewage Field, Bed or Pit
Animal Pens and Yards
50
100
100
200
200
15
30
30
60
60
Consult the SLnLe Regu-
latory Agency for
special locdJ require-
ments .
Note: - Each well has a characteristic radius of influence which depends
upon the drawdown. Care should be taken to separate the wells so tlicy
do not significantly influence the yield of each other or neigh-
boring wells and springs.
- The water purveyor should obtain control over the use of land
within at least 100 feet of the well, 200 feet is preferrable.
The lack of specific distances for other potential sources of con-
tamination such as streams, refuse disposal sites, waste lagoon, waste
treatment facilities, ponding areas, and petroleum and other chemical
storage tanks, does not minimize their potential hazard. These must be
evaluated m each specific situation. Wells which terminate in creviced
formations, particularly where the overlying soil formation is shallow
and/or highly permeable, require greater protective distances.
YIELD OF WELLS
The amount of water that can be pumped from a well depends on the
character of the aquifer and the construction of the well. Contrary to
popular belief, the diameter of the well casing is not the critical factor.
The casing diameter should be 'chosen to provide enough room for proper
installation of the desired pumping arrangement. Table 5-2 lists the re-
commended well casing diameter for various anticipated well yields. Pump
manufacturers and well drillers should be consulted before making final
choices. In unconsolidated soils where well screens may be necessary, the
required screen area may influence the casing diameter.
5-3
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Table S-2.: Recommended Well Diameters (From Individual
Water Supply by stems, £,PA)
Anticipated
Well Y:eld
in GPM
Nominal Size
of Pump Bov/ls
in Inches *
Optimum Size
of We 11 Casing
in Inches
Less than 100
75 - 175
150 - bOO
350 - 650
4
5
6
6
6 Inside diameter
8 Inside diameter
10 Inside diameter
12 Inside diameter
* To convert to millimeters, multiply by 2.54
Figure S-l: Draudo\/n Purine; Pumping
DrawCo /n during pumping :cs'
arer l<
. n£.
\
Pumpi ng
Leve
\
r Ground arer level
J—l>Q_tauL Pumr
/
/ r
/ Diowdown
-------
Quite often, the capacity of a well may be increased by drilling
deeper into the aquifer - assuming, of course, that the aquifer has the
necessary thickness. In and and gravel formations, the inlet area of
the well screen is also important in determining the yield of the well.
The amount of "open area" in the screen exposed to the aquifer may be
critical, wells completed in rock formations are usually of open hole
construction; i.e., there is no casing in the aquifer itself and the
amount of rock exposed in the well hole will influence the yield.
It is not always possible to predict accurately the yield of a given
well before its completion. Knowledge can be gained, however, from
studying the geology of the area and interpreting the results obtained
from other wells constructed in the vicinity. This information will be
helpful m selecting the location and type of well most likely to be
successful.
A common way to describe the yield of a well is to express its
capacity in relation to the drawdown during pumping. This relationship
is called the specific capacity of the well and is expressed in gallons
/ 2^
per minute (gpm) per foot of drawdownv '. The specific capacity may
range from less than 1 gpm per foot of drawdown for a poorly developed
well or one in a tight aquifer, to more than 100 gpm per foot of drawdown
for a properly developed well m a highly permeable aquifer.
(2) Metrjr: T,iters per second per meter of drawdown.
5-5
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TYPES OF WELLS
There are several construction techniques used to
desired ground water formation. Some of these methods are not considered
satisfactory for public water systems because of the inherent difficulties
of insuring adequate protection. These include dug, driven and bored
wells. These wells are generally limited to shallow, soft aquifers, wells
using these sinking methods should not be constructed for use as public
water sources unless specifically approved by the state regulatory agency.
The Manual of individual water Supply Systems (EPA) (Ref. No. 2) contains
descriptions of these methods.
The preferred method of constructing a well is by drilling, although
jetting is also considered satisfactory. Drilled wells can be constructed
in all instances where driven and jetted wells might otherwise be used and
in many areas where dug and bored wells are constructed. The larger dia-
meter of a drilled well as opposed to that of a driven well permits use of
larger pumping equipment that can develop the full capacity of the aquifer.
Drilled wells, construction of a drilled well is ordinarily accom-
plished by one of two techniques - percussion or rotary hydraulic drilling.
The selection of the method depends primarily on the geology of the site
and the availability of equipment.
WELL CONSTRUCTION
It is not within the scope of this manual to describe in detail the
current practices of well construction, particularly since a specific
manual on the subject is readily available. The reader is referred to
The Manual of Water well construction Practices, EPA - 570/9-75-001 pre-
pared under the auspices of the National Water well Association (Ref. No.
16) and published by the U.S. Environmental Protection Agency. The manual
includes formats for well construction contract documents and detailed
well construction technical standards.
-------
DRILLING METHODS
Percussion (Cable-Tool) Method. Drilling by the cable-too] or per-
cussion method is accomplished by raising and dropping a heavy drill bit
and stem. The impact of the bit crushes and dislodges pieces of the forma-
tion. The reciprocating motion of the drill tools mixes the drill cuttings
with water into a slurry at the bottom of the hole. This is periodically
brought to the surface with a bailer, a 10 to 20 foot long pipe equipped
with a valve at the lower end.
Caving is prevented as drilling progresses by driving or sinking into
the ground a casing slightly larger m diameter than the bit. when wells
are drilled in hard rock, casing is usually necessary only through the
overburden of unconsolidated material. A casing may be necessary in some
rock formations to prevent caving of beds of softer materials.
Hydraulic Rotary Drilling Method. The hydraulic rotary drilling
method may be used in most formations. The essential parts of the drilling
assembly include a derrick and hoist, a revolving table through which the
drill pipe passes, a series of drill-pipe sections, a cutting bit at the
lower end of the drill pipe, a pump for circulation of drilling fluid, and
a power source to drive the drill.
In the drilling operation, the bit breaks up the material as it rotates
and advances. The drilling fluid (called mud) pumped down the drill pipe
picks up the drill cuttings and carries them up the annular space between
the rotating pipe and the wall of the hole. The mixture of mud and cuttings
is discharged to a settling pit where the cuttings drop to the bottom and
mud is recirculated to the drill pipe.
5-7
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When the hole is completed, the drill pipe is withdrawn and the casiny
placed. The drilling mud is usually left m place and pumped out alter the
casing and screen are positioned. The annular space between the hole wall
and the casing should be grouted in non-water-bearing sections, but may
be enlarged and filled with gravel at the level of water-bearing strata.
(See Well Grouting in this Chapter)
Air Rotary Drilling Method. The air rotary method is similar to the
rotary hydraulic method in that the same type of drilling machine and tools
may be used. The principal difference is that air is used rather than mud
or water. In place of the conventional mud pump, air compressors are used.
However, some drillers equip the rig with a mud pump to increase the versa-
tility of the equipment.
The air rotary method is adapted to rapid penetration of consoli-
dated formations, and is especially popular in regions where limestone is
the principal source of water. It is not generally suited to unconsolidated
formations where careful sampling of rock materials is required for well-
screen installation. Small quantities of water are readily detected during
drilling, and the yield may be estimated.
Down-the-Hole Air Hammer. The down-hole penumatic hammer combines the
percussion effect of cable-tool drilling and the rotary movement of rotary
drilling. The tool bit is equipped with tungsten-carbide inserts at the
cutting surfaces. Tungsten-carbide is very resistant to abrasion.
5-8
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Well Log
A well log is a record of the thickness anc characteristics of the
soil, rock and water formations encountered during the sinking of the well.
Well casing and well grouting details should be shown. Static and pumping
water levels and well yields are also recorded. The log is prepared by
the driller and should be retained by the system owner for future reference.
The well log is used to determine the proper casing depth, the depth and
design of the well screen and to assist in the selection of the pump design.
The log will also be helpful for use in the future if rehabilitation or
reconstruction of the well is necessary. Some states require that the well
log be filed with the State agency responsible for well construction. A
well log form is shown in Figure 5-2.
5-9
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WATER WELL RECORD
Acr 294 PA 13Gb
MICHIGAN DEPAHTMENT
or-
PUBLIC HEALTH
County
Township N unc
f-rtiilio'i
Si ."lion Numbci
v.
%
OUII Nlll' I
H imji N<»'i >or
E'W
Distance And Duection from Road Intersections
Street address & City of Welt Location
3 OWNER O At LI
Address
Locate with ' X" in section below
Sketch M
-------
WELL CASING AND PIPE
Casing is installed in wells to prevent the collapse of the walls
of the bore hole, to exclude pollutants (either surface or subsurface)
from entering the water source, to provide a column of stored water and
to provide a housing for the pump mechanisms and pipes.
The casings must be strong enough to resist the pressures exerted
by the surrounding materials, forces imposed on it during construction, and
corrosion by soil and water environments, it must be of the proper
length to accomplish its purpose of providing a channel from the aquifer
to the surface through unstable formations and through zones of actual
or potential contamination. Casings should extend above potential levels
of flooding and should be protected from flood water contamination and
damage, if it is impossible to extend the casing above potential flood
levels, the State agency should be consulted for advice and requirements.
In unconsolidated soils, the casing should extend at least 5 feet (1.5
meters) below the estimated maximum expected drawdown level. In con-
solidated rock formations casings should extend 5 feet (1.5 meters) into
firm bed rock and sealed into place.
Steel casing is usually used for well construction. Plastic well
casing (PVC) is occasionally used in some parts of the country but should
not ,be used unless approved by the State regulatory agency. Other less
common casing types include concrete, fiberglass, asbestos-cement, stainless
steel and other alloys, both ferrous and nonferrous.
A number of technical and scientific organizations are active in pro-
mulgating pipe and casing specifications. Prominent and most active are
the American Society of Testing Materials (ASTM), the American Petroleum
institute (API), the American Water Works Association (AWWA), and the
National Sanitation Foundation (NSF) for plastic pipe. The
5-11
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specifications serve an important function by providing uniform standards
of construction and a quality warranty. However, not all materials are
covered by standard specifications.
There are three principal types of tubular-steel products which are
satisfactory for water well casing. The first is line pipe and standard
pipe made to conform to standards of the American Petroleum Institute
(API) or American Society for Testing Materials (ASTM). Casing fabricated
from structural steel plate to conform to ASTM specifications is the second
type. The third is well casing steel for which there are no standard
specifications at present. The Manual of Water Well Construction
Practices lists several specifications which may be used. Those most
usually called for are the ASTM-A-589, ASTM A-120, ASTM A-53, API 5-L, and
the Federal specification WW-P-406B.
Thermoplastic well casing pipe and couplings should conform to stand-
ards set forth in ASTM F-480-76. Only the more common sizes are covered.
Generally speaking, well casings of less than 6 inches (15.24 cm)
nominal inside diameter are not recommended for wells used for public
systems. Steel casing with a wall thickness of at least 1/4 inch has
proven reliable and is a good choice except under very corrosive water
conditions where greater thickness may be indicated.
WELL GROUTING
The annular open space left around the outside of the well casing
during construction is one of the principal avenues through which unde-
sirable water and contamination may gain access to a well. The most
satisfactory way of eliminating this hazard is to fill this annular space
with cement grout. To accomplish this satisfactorily, careful attention
should be given to see that:
5-12
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1. The grout mixture is properly prepared.
2. The grout material is placed in one continuous mass.
3. The grout material is placed starting from the bottom of the
space to be grouted and continued upward.
The specific grouting requirements of a well will depend upon the
existing surface conditions, especially the location of sources of pollu-
tion, and the subsurface geologic and hydrologic conditions. In order to
achieve the desired protection against contamination, the annular space
must be sealed Co whatever depth is necessary, but in no case less than
20 feet.
Grouting materials include neat cement grout, concrete grout and
sand cement grout. Methods of grout placement include: bailer dumping,
gravity filling, tremie pouring, positive placement, continuous injection
and the displacement methods.
Well grouting material specifications, installation methods and
testing methods are described in detail in the previously mentioned Manual
of Water Well Construction Practices. (Also Reference Nos. 12, 18, 19 and 20
in Appendix C.)
WELL SCREENS
Screens are installed in wells to hold back unstable aquifer material yet
permit free flow of water into the well through the specially designed screen
openings. The well screen should be of good quality (corrosion resistant,
hydraulically efficient and good structual properties) and should be based on
a sieve analysis of carefully selected samples of the water-bearing formation.
The analysis is usually made by the screen manufacturer or dealer, who will
pr&vide complete information to assist in the most appropriate design.
Slotted casing or perforated pipes should not be used in place of pro-
perly designed, quality well screens. Experience has shown that slotted
casings and perforated pipes corrode excessively, resulting in loss of
screening effectiveness and well and pump failure.
5-13
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The methods of screen installation and specifications are described
in detail in the Manual of Water Well Construction Practices. The methods
include: washing method, pull back method, driven through casing method,
bailed through casing method, bailed or air jetted through casing method,
washed through casing method, and the suspended from surface method.
DEVELOPMENT OF WELLS
Before a well is put into use, it is necessary to remove silt, fine
sand and drilling mud from the well hole and the water formation adjacent to
the well screen (if used) by one of several processes known as "development."
The development procedure unplugs the formation and produces a natural filter
of particles of high permeability surrounding the well screen. After the
development is completed, there will be a well-graded, stabilized layer of
coarse material which will entirely surround the well screen and facilitate
the flow of water in the formation into the well.
The simplest method of well development is surging. In this process
the silt and sand grains are agitated by a series of rapid reversals in
the direction of the flow of water and are drawn toward the screen through
larger pore openings. A well may be surged by moving a plunger up and
down in it. This action moves the water alternately into and out of the
formation. When water containing fine granular material moves into the
well, the particles tend to settle to the bottom of the screen. They can
be removed subsequently by pumping or bailing.
One of the most effective methods of development is the high-velocity
hydraulic-betting method. Water under pressure is ejected from jet orifices
and passes through the screen openings, violently agitating the aquifer
material. Sand grains finer than the slot size move through the screen
and settle to the bottom of the well from which they are subsequently re-
moved by bailing or flushing out of the top of the casing with the wash
5-14
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water. Conventional centrifugal or piston pumps may be used, as may the
mud pump of the rotary hydraulic drill. Pressures of at least 100 psi
should be used, with pressure greater than 150 psi preferred. High-
velocity jetting is particularly suited for screens of continuous horizon-
tal slot design. It has also proven effective in washing out drilling
mud and cuttings from crevices in hard-rock wells.
Other methods of development are interrupted pumping, air jetting,
use of chemicals, and sometimes in consolidated material, explosives when
used by experts. The method of development must be suited to the aquifer
and the type of well construction. Proper development is an important
part of well construction and will have a 'Significant effect on the yield
and "life" of the well.
TESTING WELL FOR YIELD AND DRAWDOWN
In order to properly design the well pumping systems, tests should be
made after the well has been developed to determine its yield and drawdown
characteristics. The tests should include pumping at predetermined constant
rates for a period of at least A hours after the drawdown has approached
stability. The water level during each pumping test is recorded, including
the maximum drawdown. After each test, the pump is shut down and the well is
allowed to recover. The water level during recovery is recorded hourly.
Failure to recover substantially within 12 hours is reason to question the
dependability of the well for that pumping rate. The safe yield will be the
rate of pumping which results in an acceptable drawdown with substantially
complete recovery of the water level within 12 hours. Measurements should be
made accurately if the results are to be considered reliable. The tests should
be done by competent drillers or engineers. Additional information regarding
the testing of wells for drawdown or yield may be obtained from the U.S.
Geological Survey, the State regulatory agency, or the manufacturers of well
screens or pumping equipment. References 12, 18, 19 and 20 in Appendix C are
also good reference sources.
5-15
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Water table wells are more affected than artesian wells by seasonal
fluctuations in ground water levels, when testing a water table well for
yield and drawdown, it is desirable, though not always practical, to test
it near the end of the dry season, when this cannot be done, it is impor-
tant to estimate as nearly as possible (from other wells tapping the same
formations) the additional seasonal decline in water levels which may be
expected. This additional decline should then be added to the drawdown
determined by the pumping test, to arrive at the ultimate pumping water
level. Seasonal declines of several feet in water table wells are not
unusual, resulting in reduced capacity in the dry season.
COMPARISON OF /TOLL YIELD WITH PEAK REQUIREMENTS
If it is planned to pump the wells into a gravity storage reservoir
system (See Chapter 6), the wells should have a safe capacity (yield) at
least equal to the maximum daily demand; or the average daily water demand
with the largest well out of service. The storage reservoir should have
a storage capacity equivalent to at least one day at the average daily
water use.
If, on the other hand, it is planned to use an hydropneumatic pumping
system, it is desirable that the well and pump capacities should be capa-
ble of meeting the peak system demand (See Chapter 6, Hydropneumatic
Systems).
WELL HEAD COVERS OR SEALS
Every well must be provided with approved seals at the top of the
casing or pipe sleeve connections to prevent contaminated water or other
material from entering the well. A variety of covers and seals are avail-
able to meet the variety of conditions encountered but the principles and
the objective of excluding contamination are the same.
5-16
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After the casing has been sealed in the ground with a cement grout,
contaminated water will not be able to seep around the casing into the
aquifer. However, unless the lop of the casing and any special openings
which are cut or provided in the walls of the casing to carry the well
pump pipes, electric supply, electrical controls, and vents are properly
sealed, contaminated water may enter the well casing through these
openings. If openings are cut or provided in the wall of the well casing
below ground level, pitless adapters are inserted into the openings to
serve as a conductor. These adapters must provide a water tight seal.
In this case the top of the casing usually extends above ground and is
covered with a special cap with an overlapping flange designed to restri
entry of foreign matter and rain, but it is not necessarily water tight.
If, on the other hand, the well pipes, conduits, etc. come through the top
of the casing, the water tight seal must be at that place and a special
venting arrangement: is necessary in most cases.
Casings should not be left open after completion of the drilling,
grout sealing of the annular space and development. The casing should oe
covered to prevent access of foreign material and vandalism.
A well slab poured around a casing is not an effective sanitary
defense when used as a su1sbitute for cement grouting of the annular space
The cement grout formation seal must be used. However, there are situa-
tions that call for a concrete slab or floor around the well casing to
facilitate cleaninc and improve appearance or ii. the construction of an
above ground pump station over the well, when such a floor is necessary,
it should be placed only after the formation seal and any well seals have
been inspected.
5-17
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Well covers and pump platforms should be elevated above the adjacent
finished ground level and should be sloped to drain away from the well casing.
Well pits should not be used as they may result in contamination. Pumproom
floors should be constructed of reinforced, watertight concrete, and carefully
sloped to a drain away from the well so that surface and waste water cannot
stand near the well. The minimum thickness of a slab or floor should be 4
inches (10.2 centinieters). Concrete slabs or floors should be poured separately
from the cement formation seal and when the threat of frost heaving exists,
insulated from it and the well casing by a plastic or mastic coating or sleeve
to prevent bonding of the concrete with the formation seal.
All water wells should be readily accessible at the top for inspec-
tion, servicing, and testing. This requires that any structure over the
well be easily removable or an opening provided to insure full, unobstructed
access for well-servicing equipment.
SEALS INSTALLED ON THE TOP OF THE CASING
Some well seals are designed for insertion into the top of the casing.
Several designs are available based upon the principal of an expandable
neoprene gasket compressed between steel plates and provided with openings
to accept pipes, electrical cables, and a vent. See Figures 5-3 and 5-4.
They are easily installed and removed for servicing. However, these seals
are generally not approved for burial and should only be used where they
extend 8 inches or more above the ground and are not subject to flooding.
This limits their use to climates which do not experience freezing tempera-
tures, unless the unit is enclosed by an above ground pump house or structure.
Burial of this seal under several feet of earth is unacceptable because
experience has shown: (1) it discourages inspection and maintenance, (2) it
is often unreliable as a seal, (3) contamination is likely during serv^cin'j,
and (4) excavations to expose the top of the well risks damage to the well,
seal, vent and electrical connections.
5-18
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Figure 5-3: Well seal for .jet pump installation
"Drive Water*
Pipe
Pumped
Water"
Pipe —
(Reproduced from EPA Manual of Individual Water Supply Systems,
Figure 8, Page 46)
5-19
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Well seal for submersible pump installation.
Oischorge
Line ^
Submersible
Pump Coble
Drop Pipe from
Submersible
Pump -
(Reproduced from EPA Manual of Individual Water Supply Systems,
Figure 9, Page 47)
5-20
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PITLESS WELL HEAD SEALS
Because of the flooding and pollution hazards involved, a well pit
to house the pumping equipment or to permit accessibility to the top of
the well is not recommended. Some States prohibit its use.
Commercial units generally known as "pitless adapters" or "pitless
units" are readily available to eliminate the need for well pits. These
units vary somewhat in design but generally include a special fitting
designed for mounting on the side of the well casing or a pre-assembled
casing extension. The well discharge and other piping are screw threaded
into the fitting. A mated fitting is designed to support the discharge
and other piping in the casing and is inserted through the top of the
casing. This lift out device mates with the fitting mounted on the outside
of the casing by compression and a locking arrangement, providing a seal
between the mated gaskets. Under this arrangement, the top of the well
casing should extend above ground level 8 inches or more and be capped with
a self-draining cover with overlapping flanges to prevent entry of
extraneous material. Figures 5-5 through 5-8 show some of these units.
The pitless system permits the connection of the well piping to the
casing underground below frost depth and at the same time provides for good
accessibility to the well casing for repairs without excavation.
There are numerous makes and models of pitless adapters and units.
Hot all are of good design, and a few are not acceptable.
7he State regulatory agency should be consulted to determine what designs
are acceptable.
5-21
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3oth the National Sanitation Foundation^and the Water Systems
Councilhave adopted criteria intended to assure that quality materials
and workmanship are employed in the manufacture and installation of these
devices. Unfortunately, the sanitary safety of the installations is
highly dependent on proper installation.
There are two general types of pitless installations. One, the
pitless adapter, requires cutting a hole in the side of the casing below
the ground surface, usually below the frost line. Into this opening there
is inserted and attached a fitting to accommodate the discharge line from
the pump. Its design varies depending on whether it will accomodate only
the pressure line or both pressure and suction lines (two-pipe jet
pump system). The other part of the adapter is mounted inside the well
casing, supporting the pumping components suspended in the well. Water-
tight connection is accomplished by a system of rubber seals compressed
by clamps or by the weight of the equipment itself.
The second type - the pitless unit - requires cutting off the well
casing at the required depth and connecting the entire unit with all
pre-assembled attachments to the casing, usually with water tight threads.
Regardless of the type of device employed, certain problems arise
which call for special care, described as follows.
1. Welding below ground, in cramped quarters and under all-weather
conditions, is not conducive to good workmanship. If welding must be done,
the welder should be an "expert" pipe welder, and he should have ample room
for freedom of movement and ease of visual inspection. A clamp-on,
gasketed pitless adapter is easier to install, but requires a smooth and
clean surface for the gasket.
(3) National Sanitation Foundation, Post Office Box 1468, Ann Arbor,
Michigan 48106.
(4) Water Systems council, 221 yorth LaSalle Street, Chicago, Illinois 60601.
5-22
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2. The pitless unit is manufactured and tested under Factory con-
ditions. However, its attachment to the casiny may present special
problems. If the well casing is threaded and coupled (T&C), it may he
possible to set the height of one of the joints so that it is at the right
height for attachment of the unit, if this cannot be done, or if welded
joints have been made, the casing must be cut off at the proper depth
below ground and then threaded.
3. Clamps and gaskets are used for attachment of 20th adapters and
units. Because of their relative structural weakness, the joint may be
broken or damaged during construction, or by frost-heave action, resulting
(5)
in leaks and potential contamination
Watertight joints require good contact between the gasket and the
sealing surfaces. Machined surfaces provide better seals. When a rubber
gasket is used as a seal against the casing, special care must be taken to
assure that the contact surface is clean and smooth.
4. Materials used in adapters, adapter units, and accessories should
be selected carefully for strength and resistance to corrosion. Dissimilar
metals which may corrode by galvanic action should be insulated from each
other by rubber, plastic, or other non-conductor. Care should be taken m
the selection of welding materials as the welded connection may be the focal
point of corrosion.
5. Excavation around the well produces unstable soil conditions, and
later settlement is to be expected. Settlement of the discharge line mny
place a load on the adapter connection which could result in breakage or
leaks. If for some reason the use of rigid pipe is necessary, these risks
may be reduced by the use of non-rigid pipe connections, a "gooseneck", a
"swing joint", or other devices which will adjust to the settlement without
transferring the load to the adapter. 3ack-fillmg with sand settled with
water will minimize settlement of the fill (See Figure 5-8).
(5) Some States prohibit the use of ''Dresser type" connections for pitless
units.
5-23
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6. After a pitless unit has been installed and tested and back-filled,
there remains the risk of accidental damage to the buried connections by
bulldozers and other vehicles. Until all construction and grading around
the area has been completed, the well should be marked with a post and
flag. If the well is located in an area where motor vehicles are likely
to be operated, the final installation should include protective pipe
posts set in concrete. The posts should be just high enough to protect
the well, but not so high that they would interfere with well servicing.
INSPECTION AND TESTING OF PITLESS DEVICES
Pitless adapters and units are installed within the upper 10 feet of
the well structure, the zone of greatest potential for corrosion and con-
tamination. The buyer should select an adapter or unit that satisfies
State agency requirements and a dealer who will stand behind the product.
Employing a contractor with a reputation for good work is perhaps the best
assurance of getting the job done right, inspection and testing should be
included as part of the contract. Some State agencies license or certify
contractors authorized by law to construct wells and install pumping systems.
Leaks found in rubber or plastic seals should be closed by tightening
the clamps, if possible. If a cement sealant must be applied, it should
provide a strong flexible bond between the sealing surfaces, and should be
formulated to provide long service under buried conditions.
5-24
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Figure $-5: Clamp-on pitless adapter for submersible
pump installation.
Lift-Out Device
.Frost Line
O-Ring Seals
^Discharge Line
Locking Device
Discharge Lint
(System Pressure)
3
(Excavation)
Drop Pipe
Check
Snifter ~ 3
U
Submersible
Pump Power
Cable
A
7s Vj>/ve. uJ IffK /
-------
Figure 5-6 s Pitless unit with concentric external
piping for .jet pump installation^
Threoded Held Connection
Lift-Out Device
Frost Line
"(/-Ring Seals
From Pump"
(Excavation)
Suction Line *->¦
To Pump
Grout
tion Seal
(Reproduced from EPA Manual of Individual Water Supply Systems,
Figure 22, Page 112)
5-26
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Figure 5-7: Weld-on pitless adapter with concentric
external piping for "shallow well" pump
installation.
.Lift-out Device
Space between Pi|
Suction Line
(Reduced Pressure)
(Excavation)
Locking
Device
(Reproduced from EPA Manual of Individual Water Supply Systems,
Figure 23, Page 113)
5-27
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Figure 5-8! Pitless adapter with submersible pump
installation for basement storage.
ation
SobmerelM«H«"
BawwfcCqMToi
fStte«S Adapter
^"DisoScrge
i-yFllf^hj' V; «
/-.FlWifcie t
Union
IWatuproc:
LSealdnfr..'
Snifter Valve or
Sanilory Well Cover (Vented)
Basement Wall
Power
Fused Disconnect Switch
>r Circuit Breakc
Pump Controls
Pressure Tank
X-
Pressure
Switch &
Gage^K Aj(. >^|urne
vJ-c"M
Outlet
Backer
Screen . .
Aquifer
Subroersftle Pump
i*- s . I ¦
•'•*/: V;\> -
(Reproduced from EPA Manual of Individual Water Supply Systems,
Figure 24, Page 114)
5-28
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WELL DISINFECTION
Disinfection is the final step m the completion of a well, its
purpose is the destruction of all potential disease-producing and other
undesirable organisms introduced into the well during the various con-
struction operations. Entry of these organisms into the well can occur
through contaminated drilling water, equipment, materials, or surface
drainage.
The completed well should be cleaned as thoroughly as possible of
foreign substances such as soil, grease, oil and debris before disinfection.
Disinfection is achieved by the addition of a strong solution of chlorine
to the well. The contents of the well should then be thoroughly agitated
and allowed to stand for several hours, preferably overnight (See
Table 5-4). Care should also be taken to wash all surfaces above the
water level in the well with the disinfecting solution. This may be done
by pumping the chlorinated well and recirculating the water into the well
with a hose, washing all surfaces. Following this, the well should be
pumped long enough to change its contents several times and to flush out
the excess chlorine.
Chlorine is available in several forms.
Calcium hypochlorite is a popular source of chlorine. It is sold in
chemical supply and most hardware stores and in swimming pool supply
outlets in the granular and tablet form containing 70 percent of avail-
able chlorine by weight. It is fairly stable when dry, retaining 90
percent of its original chlorine content after one year's storage.
Because it loses its strength and becomes quite corrosive when moist, it
should be stored under cool, dry conditions. Enough calcium hypochlorite
should be added to the water standing in the well to produce a solution
of strcnytli ranging from 100 to 200 parts per million (ppm) by weight„
5-29
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See Tables 5-3 and 5-4 for information on the amount of chlorine necessary
to achieve satisfactory disinfection. For convenience of application, a
solution is made by mixing the calcium hypochlorite in a container of
water. Stir the mixture thoroughly before allowing to settle. The
clearer liquid is then poured off for use in the well. The solution
should be prepared m a thoroughly cleaned glass, crockery, plastic, or
rubber lined container. Metal containers may be damaged by corrosion.
Solutions should be prepared to meet immediate needs only, as it loses
strength rapidly unless stored in tightly covered dark glass or plastic
containers. Storage of the chemical in the dry form is much more desirable.
Sodium hypochlorite is a liquid form of chlorine and is more con-
venient to use. It may be purchased in varying strengths of up to about
15 percent available chlorine. In its most common form, household laundry
bleach, it has a strength of about 5.25 percent of ava:.lable chlorine.
Two quarts of chlorine bleach added to each 100 gallons of water in the
well produces at least 200 ppm dose of chlorine (See Tables 5-3 and 5-4).
The chlorinated water in the well should be pumped through the pump
system to fill all pumps and appurtenances. The volume of water required
to fill these pipes and appurtenances should be taken into account in
calculating the chlorine requirements. The chlorinated water should
remain in the system for at least 2 hours t£> 12 hours depending on the
dose, then flush until the strong odor of chlorine disappears, recircula-
tion of the chlorinated water back into the well with a hose will insure
good mixing.
The water from flowing artesian wells is generally free from con-
tamination by disease-producing organisms after it is allowed to flow
to waste for a short while. If, however analyses show persistent con-
tamination, then the well should be disinfected by lowering a perforated
5-30
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Table 5-3: Storage Capacities of Well Casing
Diameter
of well
(inches)
Storage in Gallons
for Each Foot of
Depth
4
0.654
5
1.02
6
1.47
7
2.00
8
2.62
9
3.31
10
4.09
Table 5-4: Well Disinfection
Dose
Per 100 Gallons
of
Water in Well Casing
Calcium
Chlorine Hypochlorite
Dose 7096
Sodium
Hypochlorite
5.25%
Contact
Time
100 ppm 2 ounces or 4
(mg/1) heaped table-
spoons
1 quart
12 hours
200 ppm 4 ounces or 8
(mg/1) heaped table-
spoons
2 quarts
2 hours
Note: For Metric Conversion
1 inch = 2.54 centimeters
3.28 feet = 1 meter
1 quart = 0.946 liters
1 ounce by wt. = 28.35 grams
5-31
-------
container such as a short length of tubing capped at both ends, filled
with an adequate quantity of dry calcium hypochlorite, to the bottom of
the well. The natural up-flow of water in the well will distribute the
dissolved chlorine throughout the full depth of the well. A stuffing
box can be used at the top of the well to partially, or completely,
restrict the flow and so reduce the chlorine losses.
BACCmiOLCGICAL TESTS FOLLOWING DISINFECTION
After disinfection and thorough flushing to remove chlorine, a sample
of the water produced should be collected for bacteriological analysis.
If contamination is found, the well should be redisinfected to the satis-
faction of the State regulating agency, if after repeated disinfection,
the well continues to produce water showing bacterial contamination, the
problem should be discussed with the State regulating agency. Con-
tinuous chlorination may be necessary.
ABANDONMENT OF WELLS
Unsealed, abandoned wells constitute a potential hazard to the public
health and welfare of the surrounding arej. All abandoned wells must he
properly sealed to reduce these hazards. Proper sealing of a well will
eliminate the physical hazard, prevent possible contamination of the
ground water, conserve the yield and hydrostatic pressure of the aquifer,
and reduce the chances of cross-contamination between aquifers.
The basic concept involved in the proper sealing of an abandoned
well is to restore the integrity of the well hole to prevent the movement
of water up or down the hole. This is accomplished by filling the well
hole with concrete, cement grout, neat cement, or clays that have sealing
characteristics similar to those of cement, in dug or bored wells, as
much of the lining should be removed as possible so that surface water
will not reach the water-bearing strata through the lining.
Abandoned wells should never be used for the disposal of sewage or
other wastes.
5-32
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Types of Pump and Characteristics - Sanitary Protection,
WELL PUMP SYSTEMS Pumphouse - Hydropneumatic Systems - Gravity Storage
Systems
INTRODUCTION
There as a wide choice of pumps and appurtenances to meet essentially
all conditions encountered in the design and selection of well pumping
systems. This Chapter discusses the more common pumping systei.i arrange-
ments, the various types of pumps available, pump characteristics, sanitary
protection, the pumphouse and other related matters. Since the hydropneu-
matic (pressure tank) system is used extensively for small public systems,
the design of these systems is presented in considerable detail. The use
of well pur.'p systems in conjunction with gravity storage is also discussed.
If the wells are capable of supplying water at approximately the peak
water der.and rate of the system, the hydropneumatic system nay be used,
provided the practical operating pressures are within the practical range
of such systems. On the other hand, if the wells cannot be punped at or
near the peak demand rate, it may be necessary to (1) aevelop additional
wells, (2) pump the wells at their safe yield rate into a ground level
storage tank and employ a hydropneumatic system to deliver the peak demand
rate at the system pressures, or (3) pump the wells ?t tneir safe yield
into a gravity storage system. A cost analysis of the various practical
puirp systems will help in determining the most suitable arrangement.
-------
WELL PUMPS
Three types of pumps are commonly used in small public water supply
systems. They are the positive displacement, the centrifugal, and the jet.
Variations include the submersibles and turbine pumps. Special types of
pumps with limited application for public water supply systems include
air lift pumps and hydraulic rams. Pumps are further typed as shallow-well
pumps or deep-well pumps, shallow-well pumps are limited to a maximum lift
of about 22 feet (6.7 meters) as they depend upon the suction lift principal.
Deep-well pumps lift and push water (depending on the design) and may be
used to pump water from any practical depth.
Table 6-1, Pump Characteristics, lists the more common types of well
pumps, describes how it works, the advantages and disadvantages and per-
tinent remarks. The Water System Handbook published by the Water Systems
Council, 221 North LaSalle Street, Chicago, Illinois 60601, is a good ref-
erence publication. Appendix C lists several other publications on well
pumps.
SELECTION OF IUKPING EQUIPMENT
Pumps are selected on the basis of the following fundamental considera-
tions .
1. Yield of the individual wells.
2. Water consumption rates.
3. Choice of pumping system (hydropneumatic or gravity storage).
4. Capacity of pressure or gravity storage tank.
5. Size and alignment of the well casing.
6. Total operating head pressure of the pump at normal delivery
rates, including lift and all friction losses.
7. Difference in elevation between ground level and water level
in the well during pumping.
6-2
-------
8. Availability of power.
9. Ease of maintenance and availability of replacement parts.
10. First cost and economy of operation.
11. Reliability of pumping equipment.
When the well yield is low in comparison to peak demand requirements,
an appropriate increase in the storage capacity is required. The life of
an electric drive motor will be reduced if there is excessive starting
and stopping. Therefore, the water system should be designed so that the
interval between starting and stopping is as long as is practicable.
It is recommended that pump cycling rates be limited to 15 or less per
hour.
The total operating head of a pump consists of the lift (vertical
distance from well pumping level to the pump level), the friction and
velocity head losses in the pipe and fittings, and the discharge pressure
at the pump.
The vertical distance from the well pumping level to the axis of the
pump is called the suction lift, and for practical purposes shallow well
pumps using ordinary suction lift cannot exceed 15 to 22 feet of lift
(4.6 and 6.7 meters), depending on the design of the pump and the altitude
above sea level. The common shallow well pumps include the centrifugal,
the piston pump and the shallow well jet pump. These pumps must be pro-
vided with a foot valve at the bottom of the suction line or a check
valve in the suction line to hold a pump prime.
Submersible and turbine pumps do not generally operate under a suction lift
as the pump bowls are submerged in the well, the deep well jet combines
the principle of a centrifugal pump located above the well and a submerged
ejector. The practical lift of the submersible and turbine is several hun-
dred feet while the deep well jet is limited to a practical lift of 85 feet.
6-3
-------
Table£-1: Pump Characteristics. (Adapted from Rural
Water Systems Planning and Engineering Guide)
Practical LHl
How 11 Works
Advantages
Disadvantages
Remarks
RECIPROCATING OR PISTON
Shallow Well
To 22 feet
A piston is driven within a chamber and
develops a vacuum Water fills the vacuum
and is forced into the water system as the
piston reverses direction
Ca ^ p o b
C6~t>umo water containing small amounts
of sand Can be installed over small di-
ameter wells Posiiivo displacement which
means a constant rate of yield Adaptable
to hand operation
Pulsating discharge and may cause vibra
tion and noise
Can be offset from the water source
SUBMERSIBLE
Multistage
To 1 000 feet
Operates the same as a shallow-well
centrifugal pump except there are several
impellers mounted close together on a
single shall The impelleis, along wiih
the motor are placed within a watertight
housing immersed in the water source
Each impeller and its diffuser (a guide to
the next impeller) is celled a stage Sub-
mersible pumps usually require a 4" or
larger casing
Produces a smooth and even flow Easy
to frost-proof installation Short pump
shall to motor
Repair to pump or motor requires pulling
from well Easily damaged by sandy water
These pumps usually operate at 3500 rpm.
the fastest practical speed tor a 60 cycle
electric motor Pump capacity depends on
the design of the impeller The pressure
depends on the diameter speed and num-
ber of impellers
Deep Well
To 600 feel
A pump cylinder is attached to the bottom
oi the drop pipe A piston is attached to
a rod m the drop pipe As the piston is
forced up and down it pumps water up
through the drop
Same as for shallow well The open type
cylinder is easy to maintain
Same as shallow-well and the pump must
be set directly over the well
Double acting pumping barrels are avail-
able that pump 65% more water using
15% more horsepower
JET (or EJECTOR)
Shallow-Well or
Deep Well
To 22 feet for shallow-well jet and to 85
feet for deep-well jet Greater depths are
possible for deeo-well jet but at the price
of reduced efficiency
Jet pumps consist of a pump (usually
centrifugal) and a jet or ejector assembly
The assembly is installed within the pump
for shallow-well units or is installed down
in the well to make a deep well unit The
assembly consists of a body a nozzle and
a ventun tube or throat The pump forces
some water through the nozzle and venturi
lube and forces the rest of the water to
the distribution system
Few moving parts Both shallow-well and
deep well jets can be oflset from the well
High capacity at low heads Can be olfset
from the well
Easily damaged by sandy water The
amount of walcr returned to eiector in-
creases wiih increased lift 50% ol the
total water pumped at 50 feet lift and
75% at 100 feet lilt
Capacity depends on the design and
number ol impellers in the jet The pres-
sure depends on the diameter speed and
number of impellers
DEEP WELL TURBINE
Multistage
To 1 500 feet
Operates the same as a centrifugal pump
except (hat (here are one or more impel-
lers mounted close together on a vertical
shaft The bowls (each bowl is one stage
—an impeller and its diffuser) are placed
below the pumping water level with the
column (discharge pipe) and shaft extend
mg to me surface
Produces a smooth and even flow Easy
to frost proof installation Long drive
sha't requires installation m a straight
and vertical well casing
Pump repair requires pulling Irom well
Operates usually at either 1 760 rpm or
3 500 rpm depending on kind of power
used Usually used lor pumping large
quantities of water from deep wells Pump
capacity depends on the design, diameter
and speed of the impellers The pressure
depends on the diameter, speed and
number of impellers
CENTRIFUGAL
Shallow-Well
To 15 leet
A rotating wheel or impeller develops a
vacuum in the intake pipe Water fills the
vacuum end the impeller increases the
velocity of the water and forces it into a
surrounding casing shaped to slow oown
the How and convert the velocity to
pressure
Produces a smooth even How The open
impeller, but not the closed-impeller
type will pump water containing small
amounts ol sand Usually reliable and has
a good service life
loses prime easily Efficiency depends on
operating under desigr heads and speed
Very efficient for capacities over SO gal
Ions per minute and pressures less than
65 pounds per square inch An ideal
pump (or use as a boosic pump can bp
o'lsei Ifom the water source
SUBMERSIBLE
Hehcal Rotor
To 1 000 feet
A positive displacement pump mounted
with a motor in a watertight housing
Produces a smooth and even How Easy
to frost-proof Short pump shaft to motor
Will pump sand with less pump damage
than any other type
Repair to pump or motor requires pulling
from well
Pump capacity depends upon the design
of the rotors Can be used tn 4" or larger
wells
Pump caoacity depends on the size of the cylinder (displacement) and the number of
strokes per minute Pressures are limited by the strength of the pumping equipment and
the motor horsepower
6-4
-------
SANITARY PROTECTION OF PUMPING FACILITIES
The pump equipment should be constructed and installed to prevent
the entrance of contamination or foreign material either into the well
or system. The following factors should be considered.
1. Excessive use of pump lubricants may contaminate the well or
water resulting in offensive tastes, water used as a pump lubricant
must be free from contamination.
2. The sanitary well seal, pitless adapter or pump base enclosure
must prevent entrance of contaminated water and materials.
3. The pump intake assembly in the well should be located below
the maximum drawdown to prevent loss of prime. Foot valves and or check
valves should be accessible for cleaning or replacement. Only clean,
safe water may be used for priming.
4. A pumphouse may be provided, where appropriate, to insure sanitary
and frost protection and to house the controls and equipment, including a
roof hatch for well maintenance and other accessories. See Figure 6-S.
5. A well vent is recommended on all wells except those using a
packer-type jet pump which cannot work with a well vent because the casing
is subjected to positive system pressure. The vent will prevent the
development of a partial vacuum inside the well casing cis the water level
lowers. The well vent - whether built into the sanitary seal or well
cover or conducted to a point remote from the well - should be protected
from mechanical damage and have watertight connections.
The vent opening should be located above the highest anticipated flood
level. It should be screened with durable and corrosion-resistant mate-
rials (bronze or stainless steel No. 24 mesh) or otherwise constructed so
that openings exclude insects and vermin. vhere appropriate, it should
terminate in a downward position.
6-5
-------
INSTALLATION OF PUMPING EQUIFICNT
The location of the pump and assembly and motor depends on the type
of pump employed. The vertical turbine pump uses a power source located
directly over the well and with the pumping assembly submerged within the
well. The more popular submersible unit has the electric motor and the
pump both submerged within the well. The jet pump may be located over
the well or may be offset to another location. Because of the superior
performance, better operating economy and other advantages of the submer-
sible pump, it is used extensively in small water systems.
Vertical Turbine Pumps. The vertical turbine pump motor must be installed
directly over the well casing. The pump bowls are submerged within the
well and are connected by a shaft to the electric motor. The pump column
supports the bearing system for the drive shaft and conducts the pumped
water to the surface (See Figure 6-1 and 6-2).
Since the long shaft must rotate at high speed (1,800 to 3,600 rpm),
correct and stable alinement of the motor, shaft, and pump is vital to
good performance and long life of the equipment, vertical turbine pumps
should be installed by a competent workman.
Submersible Pumps. Because all moving parts of the submersible pump
are located within the well as an integral unit, this pump can perform in
mis-aligned casings that might be a problem for vertical turbine pumps.
If there is any doubt about whether there is room to insert the pump in a
casing without binding, a "dummy" pipe with dimensions slightly greater
than those of the pump may be run through the casing to make sure that the
pump will pass freely to the desired depth.
The entire weight of the pump, cable, drop pipe, column of water
within the pipe, and reaction load when pumping must be supported by the
6-6
-------
Figure 6-1: Vertical (line shaft) turbine pump mounted
on well casingi
Lock
Washer
Column
Pipe
Gasket
Support
Pump
Discharge
Head
Line
Shaft
Weld, Inside
and Out
Flat
Washer
Lock
Washer
Nut
Adequate for 6"and smaller wells
Well
Casing
(Reproduced from EPA Manual of Individual Water Supply Systems,
Figure 19, Page 105)
6-7
-------
Blow-off
iiiiiiiniii iiiiii
iiiiiiiiiiiiiiiiiii
Seal all Openings into Well
and Vent as Shown
^ Grout in Base Flange
Well casing
shall project
a m inimum
of Kj" into
Pump Base
TTTT*"' i i I i i » i i i i »
fl - - Pump House Wall
LL . iimiilHill
4
Screen
Gate Valve
Sampling Tap #2
Proper
Pressure Gauge
& Snubber
Air Release
Check
Meter
Sampl ing
Tap #1
Gate Valve
Slope to Gutter
Floor
Drain
./ %J'f9 '•
Capped 2" Pipe Welded to Casing
for Water Level Measurements
Di scharge
Well Casing
Drop Pipe
/?" Copper-Line Tapped into
Main 25' from Pump House for
Sampling Top #2
Grade
Drain Pipe
Well Casing
Drop Pipe
DESIGN FOR
LARGE DIAMETER WELLS
MICHIGAN DEPT. OF PUBLIC HEALTH
DESIGN FOR
SMALL DIAMETER WELLS
Figure 6-2
BASE DESIGNS FOR DEEP WELL TURBINE PUMPS
-------
Figure 6-3• Exploded view of submersible pump.
Power Cable
Drop Pipe Connection
WZ2
.Check Valve
. Pump Casing
'Inlet Screen
Diffusers 8 Impellers
irrnna
' Inlet Body
Power Leads
Motor Shaft
Motor Section
Lubricant Seal
(Reproduced from EPA Manual of Individual Water Supply Systems,
Figure 15, Page 59)
6-9
-------
drop pipe itself, it is important, therefore, that the drop pipe and
couplings be of good quality, heavy duty, galvanized steel pipe. Cast-
iron fittings should not be used where they must support pumps and pump
columns. Furthermore, the entire load is normally suspended from the
sanitary well seal or the "pitless" installation. Only durable units
designed for these weights should be used. (See chapter 5).
Jet Pumps. jet pumps may be installed directly over the well, or
off-set from it. Since there are no moving parts within the well,
straightness and plumbness do not affect the jet pump's performance. The
weight of equipment in the well is relatively light, being mostly pipe
(often plastic), so that loads are supported easily by the sanitary well
seal. There are also a number of good "pitless adapter" and "pitless
unit" designs for both single and double pipe jet systems. (See Chapter 5).
PUMPHOUSE AND APPURTENANCES (See Figure 6-5)
Where necessary a pumphouse should be installed above the surface
of the ground. The pumproom floor should be of watertight concrete con-
struction and should slope uniformly away from the well casing in all
directions. A thermostatically conLrolled electric heater, or a heating
cable will generally provide adequate protection when the pumphouse is
properly insulated. In areas where power failures may occur and con-
tinuity of pump operation is critical, an emergency, gas driven power
supply or pump should be considered.
LIGHTNING PROTECTION
Voltage and current surges produced m powerlines by nearby
lightning discharges constitute a serious threat to electric motors.
The high voltaqe can perforate and burn the insulation between motor
windings and motor frame. The submersible pump motor is somewhat" more
6-10
-------
Figure,6-kt
"Over-the-well" .jet pump installation.
Pressure
Switch
Centrifugal Pump-—|q ® Q Q) ©
Regulating
Pressure Gage
—^ Discharge
Stuffing Box
Impeller
Sanitary Well Seal
Mastic Seal
(Reproduced from EPA Manual of Individual Water Supply Systems,
Figure 16, Page 97)
6-11
-------
Figure 6-51 Pumphouse~
Removable
Roof/Wo II*
Shingles (
Shuttling
Insulation
Pressure Tank
Rafters
Control Bon
Ventilation
Automatic
Chlorinator.
Studs
Shuthing
Siding
Chlorine-*
-Solution
Reinforced
Concrete •
Sanitary
_Well S«
(Reproduced from EPA Manual of Individual Water Supply Systems,
Figure 20, Page 108)
6-12
-------
vulnerable because it is submerged in ground water, the natural "ground"
sought by the lightning discharge- Actual failure of the motor may be
immediate, or it may be delayed for weeks or months.
There are simple lightning arresters available to protect motors and
appliances from "near miss" lightning strikes. (They are seldom effective
against direct hits.) The two common types are the valve and the expulsion
units. The valve type is preferred because its "sparkover" voltage remains
constant with repeated operation. Arresters must be installed according to
instructions from the manufacturer and connected to a good ground, in the
case of submersible pumps, this good ground can be achieved by connecting
the ground terminal of the arrester to the submersible pump mocor frame
with a heavy stranded copper grounding wire, if the steel well casing
extends into the water table, the ground can be improved by also connecting
the grounding wire to the well casing. IMPORTANT NOTE. Connecting the
arrester to a cooper rod driven into the ground does not satisfy grounding
requirements. Similarly, if a steel casing does not reach ground water, it
will not De a reliable ground.
Additional advice on the location and installation of lightning
arrestors may be obtained from the electric power company serving the area.
HYDROPNEUMATIC SYSTEMS
Hydropneumatic systems are suitable for small pulic water supplies
but have certain inherent limitations which should be considered before
selecting them over the generally preferred gravity storage system.^ Even
when operated as pre-pressured (supercharged) systems, Che effective
(usable) storage is limited to less than 30 percent of the gross pressure
tank capacity. This effective storage will generally amount to 2 - 30
minutes at peak demands. For this reason, it is desirable that the well
yield and pump capacity approach the peak demand. If not, a ground level
(1) See Gravity Storage Systems in this Chapter for other adv,nrrKr5.
6-13
-------
storage tank may precede the pressure tank to receive water from the well(s)
at their safe yield(s) and store it for use by the pressure tank system.
Gravity storage, on the other hand, can be provided with a full day stor-
age or more to meet daily and peak flows on demand ana m addition pro-
vide considerable backup to cover both planned or unplanned interruptions
of equipment, the well(s) or other facilities. Gravity storage also has
an advantage if water for fire protection is necessary.
Furthermore, pressure tank systems operate between pre-determined
operating pressure ranges between pump cut-in and cut-out. This pressure
difference will vary with installations but usually ranges between 20 and
30 psi. Therefore, pressure fluctuations in the system are frequent, par-
ticularly when compared to gravity storage systems.
Hydropneumatic systems, as the name implies, depend upon the main-
tenance of a cushion of air in the tank which is compressed by the water
and in effect provides stored energy to force the water out on demand.
In larger systems, the air is in direct contact with the water but smaller
systems are available with a wafer, diaphragm or a bag which provides
phvsical separation between water and air. When the air and water are m
direct contact, continuous means must be provided to maintain a proper
ratio of air in the tank. Several types of air-volume control devices are
available depending on the characteristics of the water and the pump system.
Supercharging tanks with air to achieve increased operating efficiencies
and to increase the effective storage, require the installation of an air
compressor and special air controls. On and off operation of pumps is
achieved by the use of pressure control switches.
6-14
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The following terms are in common use for hydropneumatic systems:
Capacity - the gross tank capacity in gallons.
Cycle rate - the frequency of pump start and stop per hour.
Drawdown or effecnve storage or usable water - the portion of the
tank capacity represented by the amount of usable stored water between
pump shut-off and pump cut-in.
Air volume - the portion of the tank volume occupied by air.
Pump starting pressure - a pre-determined low pressure in the water
systems which activates the pressure switch to energize the pump motor
(also called cut-in pressure).
Pump cut-out pressure - the pre-determined pressure which activates
the pressure switch to shut off the pump motor.
Pre-pressurizing or supercharging - the periodic addition of forced
air to the tank by means of an air compressor in an amount greater than
the amount represented by the tank volume at atmospheric pressure. The
maximum supercharging pressure must be less than the pump starting pres-
sure, to avoid discharging air with water. Internal check valves are
available to help control this situation.
Pressure storage tanks provide the following functions:
1. Prevents rapid cycling of pump motors. Most pump manufacturers
recommend cycle rates less than 30 per hour.
2. Provide limited water storage under pressure to help meet short
term peak demands by supplementing the pump capacity and provide water
between pump cycles.
3. Provide a means of maintaining system pressures within prede-
termined limits.
4. Eliminate the need for large capacity gravity storage.
6-15
-------
Types of Pressure Storage Tanks
There are 3 basic types of pressure storage tanks; (1) conventionaJ,
(2) floating wafer, and (3) flexible separators; diaphragm and bag IvpcL.
(See Figure 6-6).
Conventional Tanks - These tanks may Jje designed for vertical or
horizontal placement and range in size from a few gallons (household
sizes) to several thousand gallons. The outlet is located near the bottom
of the tank and may be a combined inlet-outlet or they may be separated on
opposite sides of the tank. Since the air cushion is in direct contact
with the water, air volume controls are necessary. The air volume control
is located m the upper portion of the tank and provisions are available
for introduction of air for pre-pressurizing. conventional tanks arc
suitable for wide range of systems from the single family size to public
water system sizes with total Lank capacity of 10,000 gallons and more.
Floating Wafer Tanks - This design (Jee Figure 6-6) emplo\s a floating
wafer to separate the water and air. Solid rigid floats and flexible
rubber or plastic floats are used. The wafer rides or floats on top of
fhe water. Since the separation of air and water is not complete, some
I
loss of air car. be expected and occasional recharging is necessary.
Supercharging to pressures of about 2-5 psi less than the pump starting
pressure is recommended. The inlet and outlet are generally combined at
the bottom of the tank, in order to prevent premature loss of air due to
eleccric outage or over water demands, an internal air check valve should
be installed. These tanks are installed m the vertical position and the
tank capacity is therefore limited m size by the prevailing geometry.
The" are therefore limited to smaller supplies.
6-16
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Flexible Separators - These tanks may be either the bag type or the
flexible diaphragm (See Figure 6-6). The separator is fixed or fastened
around the inside of the tank to provide complete separation of air and
water. Tanks are usually supercharged at the factory to pressures just
below the pump starting pressure. An air recharging valve is provided but
is seldom used as the complete separation of air and water results in
no air loss and no air volume control is necessary. These tanks also stand
in a vertical position and are therefore limited by the geometry to smaller
public water systems.
Supercharging tanks provide improved cycle control ajid increased
drawdowns. However, since the supercharging is at or just below the pump
cut-in pressure, the tank is essentially empty of water at pump start-up.
If the demand at the time of pump start is greater than the pump capacity,
pressures in the water system will drop substantially. Therefore, separate
supplemental supply tanks are desirable. The supplemental tank is super-
charged at lower pressures than the primary tank and the differential
pressure switch ranges are set closer.
Accessories
Pressure switches are installed on the pump discharge line near the
tank inlet or in the tank itself. Switches generally have variable low
pressure (pump start) settings and variable operating ranges for pump
cut-off.
Pressure relief valves are necessary where high pressure pumps are used which
may exceed the safe tank operating pressure rating, if the pressure switch should
fail. Relief valves are installed in the inlet line as close as possible to the
pump discharge. They must be large enough to relieve the maximum rated pump
r.-i7
-------
Figure 6-6: Types of Pressure Tanks
CONVENTIONAL WAFER
DIAPHRAM WATER IN BAG AIR IN BAG
AIR
WATER
3,
. '
DIAPHRAM
W
WAT E®.
Figure 6-7: Typical installation of a pressure storage tank and centrifugal
pump for a small water supply.
Air relief valve
jf y --Water level at maximum operating pressure
Water
column
Pressure control
high and low
pressure switch
Water level at minimum operating pressure
Manhole
Air compressor
2-5 cfm for 15.000
gal tank
Pressure gage
To motor
Centrifugal pump
Gate
f/.Si,.
—Tank supports
Intake
Discharge
Gate valve
Swing check Oram
-WW
Cork pad '
Use special rubber hose fitting between pump
and pressure tank (or quiet operation
-Dram (Slope floor to drain)
Provide valved by-pass of tank
From Enulroninenlai Sanitation by Joseph A Sahaio Jr published by John Wiley & c:uns lnc New York Un8
(Reproduced by permission of Joseph A. Salvato, Jr. and John Wiley and Sons, In. .)
6-18
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capacity at operating pressures or the working pressure of the lowest
rated system component. They should be piped to a drain in such a manner
as to insure no blockage of free flow.
Air Control Valves
Air controls which will add air to conventional and floating wafer
tanks are available m two basic vacuum operated types. These controls
are satisfactory for jet pump systems which operate at 6 feet or more of
suction lift, if the suction lift is less than 6 feet as with deep well
jets, a special vacuum booster pump is necessary. The air control valve
must be sized for the system. Over sizing is no problem as the control
operates only when more air is needed. Consult the equipment manufacturer
for more details. A site glass installed on the pressure tank will readily
indicate the relative air-volume ratio.
Vacuum boosters are also used in systems operating under supercharged
(pre-pressurized) conditions. Over charging may be a problem and can be
controlled with an internal air check valve which will prevent air from
passing ouc of the tank when supercharging exceeds the pump cut-off pres-
sure. Air compressors actuated by special controls are also used with
supercharged systems.
Tankless (Constant Pressure) Systems
Several "tankless" type pressure systems are available. They are
designed to eliminate the standard type pressure tanks but all have a
small accumulator to reduce cycling. They are not applicable for public
water systems except possibly as boosters for remote parts of the distribu-
tion system. Even so, a small tank type hvdropneumatic system is more
reliable. Many state agencies disapprove tankless systems.
6-19
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Booster Pumps With Hydropneumatic Tanks
In areas where the topography varies considerably, some remote areas
may experience low pressures. A booster pump and pressure tank system may
be installed to boost the pressure as needed. The pump intake must be
under a positive pressure from the distribution system. The hyaropenumatic
system is designed to meet the demand of the remote area. Boosters may be
used in both hydropneumatic and gravity storage systems.
Pressure Tank gpecifications
Specifications for the fabrication of hydropneumatic tanks are covered by
Section VIII, Division 1, Boiler and Pressure Vessel Code, American Society of
Mechanical Engineers (ASME), 345 E. 47th St., NY, NY 10017.
Determining the Required Effective Storage Capacity
Several factors must be considered in selecting a pressure tank size
to meet the system needs. These include:
- The well pump capacity vs. the peak system demand (someizimes
referred to as the instantaneous demand).
- Operating pressures and pressure range.
- Air volume control and supercharging.
- Pump cycling rate.
If the pump and well capacity are equal to or greater than the peak
demand, a minimum size tank may be used and the pump cycling rate becomes
the critical design factor (should be less than 30 cycles per hour). Peak
demands are discussed in Chapter 3. If, however, the pump capacity is
less than the peak demand, a pressure tank large enough to supply that
part of the demand not furnished by the pump(s) should be used. The key
factor then is the determination of the peak demand of the system. Once
this is established, the other design criteria can be selected to meet the
conditions, unfortunately, reliable data on peak demands for the wide
6-20
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variety of small public water system uses is rather limited and only
selected data is available at the present. Therefore considerable judgment
may be necessary to arrive at a suitable peak demand. Until data is more
readily available, local expedience with satisfactorily functioning existing
systems of a comparable type and size, will be useful.
Various rules of thumb and design criteria are used to size pressure
tanks. They are based on experience and are usually expressed in terms of
the required effective (usable) capacity. Some of these are listed below.
1. The minimum required effective volume of a tank (gallons) shall
equal the peak demand (gpm) minus the well pumping capacity (gpm) multiplied
by 20 minutes. Where the pump capacity exceeds the peak demand, the total
tank capacity shall be not less than forty (40) times the number of resi-
dential units expressed in gallons but not less than 500 gallons. (A
requirement of the State agency in North Carolina for residential and mobile
home park systems.)
2. Based upon pump manufacturers criteria of a pump cycling rate of not
more than 30 per hour, an effective minimum storage of at least 2 times the
pump capacity expressed as gallons per minute is necessary. This is equiva-
lent to 2 minutes of usable storage. This applies only if the well pump
capacity is equal to or exceeds the peak demand.
3. If the wells and well pumps cannot supply the peak demand for the
desired period of time (20 to 60 minutes) and it is desired to use a pres-
sure tank system, the wells may be pumped at a safe continuous yield(s) into
an intermediate storage tank located near the pressure tank system. Float
switches may be provided to control on and off operation of the well pumps.
This intermediate storage tank should be sized to insure sufficient stored
water to meet the peak demand period. The minimum effective volume should
6-21
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be the difference between the peak demand requirements and the rated well
pump capacity (expressed in gallons per minute) multiplied by a time factor
which will insure sufficient stored water to meet the duration of the peak
demand. The hydropneumatic system pump draws water from the storage tank
to meet peak demand conditions.
Sizing the Tank and Selecting Pressure Operating Conditions
After determining the required effective storage capacity of a pres-
sure tank, the gross tank size and pressure operating conditions can be
determined. Several methods of design are available, most based upon the
principles of Boyles Law of Physics as it applies to the air volume-pressure
conditions within a hydropneumatic tank. The method presented is particu-
larly suited to preparing various design alternatives and the selection of
the optimum design for the prevailing conditions.
Boyles Law states that the volume that a gas occupies (in this case air)
varies inversely with the absolute pressure, provided the temperature does
not change. When air is compressed by the water entering the tank or expands
when water leaves the tank, the system follows the law for all practical
purposes.
Boyles Law: = ^2^2
Condition 1 = Condition 2
Where: P^ is the absolute pressure for condition 1, and is equal
to the gauge pressure plus the atmospheric pressure
(add 14.7 psi to gauge pressure).
is the volume or space occupied by the air in gallons
at the pressure P^.
and are the second conditions after compression or
expansion of the air by water entering or leaving the tank.
6-22
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If the above equation is solved for various conditions to simulate
various pressure operating ranges, the results may be plotted on a chart as
a family of curves. Tank size problems may be then solved graphically.
A curve can be developed to simulate conventional tank operation where the
tank is started with the air not pre-pressured. Other curves may be
developed with the initial air pre-pressurized at various pressures. If
these curves are developed for a gross tank size of 1,000 gallons, a family
of curves may be prepared for all practical operating conditions for a
hypothetical 1,000 gallon capacity tank. From the curves, the usable
(effective) water storage volume can be determined for a 1,000 gallon hypo-
thetical tank under any practical simulated condition of pre-pressuring
from no pre-pressurizing up to say 55 psi pre-pressurization. This has been
done to develop Figure 6-8. Each curve represents 5 psi increments of pre-
pressurizing as labeled across the top of the chart. The bottom of the
chart represents the cut-in and cut-out pressure of the pump. Figure 6-8
has been adopted from an article by C. Courchaine, P.E., Michigan Department
of Public Health, published in Volume 11, No. 1 - Ground Water, January-
February 1973.
Using Figure 6-8 to Size Pressure Tanks
In order to use the chart, several practical operating conditions are
selected for trial. After analysis, the conditions which produce the
optimum conditions are selected for sizing the tank. After sizing the tank,
pressure controls and air controls (including an air compressor if necessary)
are selected to best meet the selected operating conditions.
6-23
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Step 1: Effective Storage Requirements: The previous section discusses the
various methods of arriving at the desired or required effective
storage capacity of a pressure tank necessary to meet the peak
period demands. The effective storage capacity is the key factor
in proceeding with the design. Once determined, proceed to Step 2.
Step 2: Pre-Pressuring: Select various conditions of pre-pressurization
(supercharging) from none (zero), up to about 5 psi below the
cut-in pressure. Use gauge pressure, not absolute, as the curves
are developed for gauge pressure.
Step 3: Pressure Operating Range: Select various pump cut-in and cut-out
operating ranges to meet the system pressure requirements at the
peak demands. Common ranges for public systems are 25 to 35 psi
cut-in to 45 to 65 psi cut-out. Use gauge pressures, not absolute.
The pump(s) must be selected to operate efficiently under these
pressure conditions.
Step 4: Using the Curves: With a given set of pressure operating condi-
tions (including pre-pressure), proceed as follows using Figure 6-8.
- At cut-in pressure (left side of chart), draw a light pencil line
to right until it intersects the selected pre-pressure curve,
mark the point and draw a pencil line vertically downward to
intersect at bottom of chart, "Volume of Water in Gallons."
- Do same for cut-out pressure.
- The difference between the volume of water (from the chart) for
the cut-out and cut-in pressure is the usable storage for a
hypothetical 1,000 gallon gross tank.
6-24
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- Having chosen the "desired" usable storage capacity in Step 1,
divide this by the actual usable storage in the hypothetical
1,000 gallon tank and multiply by 1,000. The result is the
gross required tank size in gallons for that set of conditions.
Required Gross _ Desired Usable Storage .
Tank Size (gal.) Usable storage from chart x
- Repeat for all conditions.
- After analysis, select the optimum gross tank size to meet the
required conditions.
- Select pressure and air controls to meet the selected conditions.
Example:
Given: Well pump capacity = 40 gpm
System peak demand = 60 gpm
Duration of peak demand = 20 minutes
Effective desired storage = (peak demand - pump capacity) x 20
minutes = (60-40) x 20 = 400 gallons
To find: Optimum conditions of prepressuring, pressure operating range and
required gross tank size.
Solution: The tabulation that follows is a convenient method of setting up
the problem. In this problem 7 different pressure operating con-
ditions have been selected for analysis. Others could be chosen
as desired.
The usable storage for each of the conditions (1 thru 7) is
determined from Figure 6-8.
The required gross tank size for each of the 7 conditions is
calculated as previously described.
An analysis of the tabulated results follows the Table.
6-25
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Pp>£Pf)£ttUP>/ZED CoupmOM /A/ Psi
Tank filled
FROM ZeAO
(jAQE f^ESSURE
mPKn/Emric tanks
Useable Water Storage Per /OOO
Gallons of Gross Ianr Capacity
Under Various Prepress urizatioh
Conmtions
zoo 400 500
X/olljme of Water /a/ Gallons
sr-'&5
-------
Tabulation to Facilitate Use of Figure 6-8 to Determine Gross Pressure Tank Size
Conditions
(Psi)
Usable
Desired
Storage
Pre-
Hypothetical
Usable
Required Cross
No.
Pressure Cut-in
Cut-out
1000 gal. tank
Storage
Tank Size (gal.)
1
0
35
55
85
400
400/ 85 x 1000 = 4,706
2
25
35
55
230
400
400/230 x 1000 = 1,739
3
30
35
55
250
400
400/250 x 1000 => 1,600
4
25
35
65
300
400
400/300 x 1000 = 1,333
5
0
35
65
120
400
400/120 x 1000 = 3,333
6
20
35
65
270
400
400/270 x 1000 = 1,481
7
35
40
60
245
400
400/245 x 1000 = 1,640
Analysis: Note the significant effect of pre-pressurizing on the usable
capacity of the tank. Condition No. 4 appears at first to be the optimum
condition, that is, pre-pressurizing to 25 psi with pump operating range
of 35 psi cut-in and 65 psi cut-out, and a gross tank size of 1333 gallons.
However, the 30 psi pressure difference between cut-in and cut-out may be
undesirable. Also, the pre-pressurization is close to the cut-in pressure
and very little water will be left In the tank at cut-in. If the demand
should be higher than the pump capacity at that instant, air may spill out
of the tank. Therefore, an internal air check valve is advisable.
Further analysis shows that Condition No. 3 or No. 7 will be the best over-
all choices.
If tanks are not manufactured in the size determined by the analysis, choose
the next largest tank size.
6-27
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GRAVITY STORAGE SYSTEMS
Well supplies are often pumped directly to a gravity distribution
reservoir (tank.) from which water flows on demand to the points of
use. The wells may also be pumped directly into the distribution system
with the tank floating (riding) on the system. Either arrangement is
acceptable. The pumps may be controlled by water level float controls or
pressure switches. The storage tank is located at an elevation which will
insure adequate operating pressures.
A gravity storage system offers several advantages over the hydropneu-
matic systems and should be considered where topographic conditions are
favorable. The larger the water system, the greater the advantages.
However, even smaller systems will find the following advantages worthy of
consideration.
- Less variations in pressure will occur.
- Storage for fire fighting purposes is possible.
- One to two days of storage may be provided to meet water requirements,
thus improving reliability and reducing the need for duplication of
facilities.
- Greater flexibility to meet peak demands.
- Wells do not need to be pumped to meet the peak system demand
requirements. Therefore, lower capacity wells may be used.
- Pumps may be sized to take better advantage of electric load factors,
thus reducing energy costs.
- On and off cycling of pumps is reduced.
- Several wells may be tied into the system and each pumped at its
most favorable rate.
6-28
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Since the gravity reservoir provides the storage necessary to meet
the peak system demands, the wells need not be developed to meet the peak
system capacities, as is generally necessary with pressure tank systems.
The wells should be capable of meeting the maximum day demand within the
period of time when water use is significant. As an example, day schools
usually exert a significant water demand only over a ten to twelve hour
day. The wells must, therefore, be pumped at a rate sufficient to meet
the maximum day demand in a 10 to 12 hour period. Under these conditions,
the reservoir (tank) should have an effective capacity equivalent to the
average daily demand.
Gravity distribution reservoirs may be elevated tanks mounted on
structural supports above ground, may be located partly below ground or
may be tanks placed on pads or cradles on the ground surface. Elevated
tanks are necessary where high ground is not available within the service
area. The operating water levels of the tank should be sufficiently above
the distribution system to produce minimum operating pressures of 35 psi
(about 81 feet of head) but preferrably 50 psi to 75 psi (116 - 173 feet).
Pressures should not exceed 125 psi (289 feet).
Note: 1 psi = 7 kilopascal (approximately)
1 ft. = 0.30 meters
Shallow reservoirs with large diameters are preferred over deep ones
with smaller diameters, other things being equal. Larger diameter tanks
have more water per foot of drawdown and are thus less prone to pressure
fluctuations. They are also less costly to build.
Prefabricated standpipes and elevated tanks are readily available
with a wide range of capacities. Pre-stressed concrete tanks are quite
popular as they are not subject to corrosion and have less maintenance.
6-29
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Reservoirs should be covered to prevent airborne contamination (birds and
algae growths which impart tastes and odors) . Access manhoes with locked cov
are necessary and built-in ladders are advisable. Tanks must be vented
(directed downward and screened) and overflows must be provided. Overflows
should be directed away from footings. Steel tanks require painting and
may require special corrosion control, such as cathodic protection devices.
The State regulating agency will provide a listing of non-toxic paints
suitable for interior tank use. Elevated tanks located near airports may
require special lighting and should be approved by the Federal Aviation
Administration or the local airport.
Over a period of time, reservoirs may accumulate organic and inorganic
debris which settles to the bottom as a sludge. This sludge can contribute
taste, odors and turbidity to the systems when it accumulates to a depth
approaching the outlet pipe. Periodic draining of the tank and cleaning is
necessary. This should be followed by disinfection before reuse.
Where the service area varies considerably in elevation, it may be
necessary to employ two or more separate pressure zones, each served by a
separate storage tank. An in-line centrifugal pump housed in a pump
station and equipped with shut-off valves and check valves may be used to
boost the pressure to the second level zone. The pump may be float or
pressure controlled. In-line submersible pumps designed specifically as
boosters are available. They fit into the water main and require no pump
station. The suction side of booster pumps must be under a positive head
at all times.
Small remote areas with low water pressure may be served by a hydropneu-
matic system located in a building or other structure. The system is sized
to meet the tributary peak demand. The pump suction must be under positive
pressure. Check valves are necessary. For design details, see the hydro-
pneumatic system section in this Chapter.
6-30
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DISINFECTION OF SYSTEM FACILITIES
Disinfection of Wells
See Chapter 5, Tables 5-3 and 5-4, for specific directions on the
disinfection of wells.
Disinfection of The Well Pumping System
(See Chapter 5, Tables 5-3 and 5-4 for chlorine doses.)
After the construction or repair of a water pumping 9ystem, the system
must be disinfected before use. The system should first be flushed to
remove dirt and loose material.
All systems should be equipped with fitting(s) to permit the addition
of chlorine disinfectants. The fittings may consist of 1/2" or 3/4" taps
equipped with brass or stainless steel valves to serve as shut-offs when
not in use. These may be located as follows:
1. A fitting should be connected to the well casing so that it may
be disinfected when needed. If the well has a vent, the vent itself may
be used for the occasional disinfection by removing the "U" turn fitting
and pouring chlorine bleach into the vent.
2. A fitting should also be provided on the pressure side of the
pumps between the pumps and the pressure tank if any. This same tap may
be used for continuous chlorination of the water as described in Chapter
9, Chlorination. To disinfect the system, determine the amount of 5.25%
chlorine bleach required for disinfection using Table 5-4 in Chapter 5
and, pump or inject this amount of bleach while filling the system, using
a high capacity hypochlorinator. The chlorine bleach may also be added
to the well casing to disinfect the entire well pump system as described
in Chapter 5.
After disinfection at the proper contact period, and after thorough
flushing to flush out the chlorine, a sample should be collected for
coliform bacteria testing to verify that disinfection is complete.
6-31
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Disinfection of Gravity Storage Tanks
After construction and before use, the storage tank must be disinfected
to destroy micro-organisms which may be present. The tank interior mut,t
first be cleaned to remove dirt and loose material.
Large tanks may be disinfected by the direct application of a chlorine
solution to the inner surface by means of a thoroughly cleaned garden type
spray can. A spray can which has been previously used for spraying toxic
chemicals, must not be used. Spray all inner surfaces with a 200 mg/1
solution of chlorine made by adding 2 fluid ounces (59 ml) of 5.25%
chlorine bleach (common household sodium hypochlorite bleach) Lo 4 gallons
(30 liters) of clean water. The solution may also be brushed on the sur-
faces. The chlorine solution should remain on the surface for at least 2
hours. The tank should be ventilated to avoid inhalation hazards. After
that the tank may be filled and tested as stated below.
Disinfection may also be accomplished by adding chlorine solutions to
the structure as it is being filled. First determine the capacity of the
tank in gallons. Add 2 quarts of 5.25% chlorine bleach for each 100
gallons of capacity for a 200 mg/1 dose. High test calcium hypochlorite
70% available chlorine may also be used. Common forms are HTH and
Perchloron. Use 1/2 lbs. for each 1000 gallons of tank capacity. Mix a
slurry in a plastic pail and add to the tank as it is being filled. After
at least 2 hours of contact, the tank may be drained. Cut the dose in
half for 100 mg/1 dose and increase the contact time to 12 hours. A 50
mg/ml dose (1/4 of above) may be used with a 24 hour retention time.
After disinfection, drain the tank and refill. A sample of the water
in the tank should be collected and submitted to an approved laboratory for
a coliform bacteria test. If the report is satisfactory, the tank may be
used. If not, repeat the disinfection until the bacteria test is satisfactory.
6-11
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Disinfection of the Distribution and Piping System
See Chapter 11 for details on the disinfection of the distribution and
piping systems.
Discharge of Heavily Chlorinated Water to Streams
After the disinfection of a water supply system with chlorine, it is
necessary to flush the system to remove the chlorinated water prior to
re-sampling for testing and prior to placing the system back into service.
Discharging the heavily chlorinated water to small streams or bodies of water
may result in fish kills or damage to aquatic life. V/hen this possibility
exists, it may be necessary to flush gradually over an extended period of
time. The flushed chlorinated water may also be stored in temporary pondb
until the chlorine dissipates to less than 1 mg/1.
6-33
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CHAPTER 7
DEVELOPING SPRINGS
Types - Development - Storage Systems - Disinfection
INTRODUCTION
In order to properly develop a spring supply, it is necessary to capture
the natural flow of ground water as it issues at the surface of the ground,
in a manner which excludes contamination of the water. Springs are subject
to contamination by sewage disposal systems, animal wastes and surface drain-
age, Springs are also susceptible to seasonal flow variations and the yield
may be reduced by the pumping of nearby wells.
Like wells, springs may be gravity or artesian.
Gravity springs occur where the water bearing stratum overlays an imner-
meable stratum and outcrops to the surface. They also occur where the land
surface intersects the water table. This type of spring is particularly
sensitive to seasonal fluctuations in ground water storage and frequently
dwindles to a seep or disappears during dry periods. Gravity springs are
characteristically low-yielding sources, but when properly developed they
may be satisfactory for small water supply systems
Artesian springs discharge from artesian aquifers. They may occur
where the confining formation over the artesian aquifer is ruptured by a
fault or where the aquifer outcrops a lower elevation. 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 con-
sequence, artesian springs may be dried by nearby well pumping.
7-1
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DEVELOPMENT OF SPRINGS(1)
There are three important criteria in the selection and development of a
Spring: (1) selection of a spring with acceptable water quality, (2) develop-
ment to the required quantity of water, and (3) sanitary protection of the
spring collection system. The measures taken to develop a spring must be
tailored to the prevailing geological conditions.
The main features of a spring collection system are as follows
(See Figure 7-1).
- The spring flow is intercepted by a system of perforated pipes
driven into the water bearing stratum or layed in gravel packed
trenches. The flow is directed into a storage tank. As an alter-
nate, a watertight concrete collection chamber is constructed with
openings in the bottom and/or a side wall to intercept the flow.
This chamber may also serve as the storage tank. The storage tank
or chamber may be sized to provide gravity storage to meet the daily
water requirements as described in Chapter 3 or the flow may be
piped to a separately located storage reservoir. Where possible,
the walls of the collection chamber should extend to bedrock or the
impervious stratum. The watertight walls should extend 8 or more
inches (20centimeters) above ground to prevent entrance of surface
water. An. overlapping (shoe box) cover will prevent entrance of debris.
- A valved drain is necessary to permit draining, cleaning and mainte-
nance.
- A screened over flow is essential.
- The valved supply pipe is inserted a few inches above the chamber or
tank floor. If the supply pipe serves the distribtuion system
directly, it must be sized to meet peak demands. See Chapter 3.
(1) Consult with the State agency for special requirements.
7-2
-------
The tank is usually constructed in place with reinforced concrete so
as 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 insure 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 in the vicinity of 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 holding back the aquifer material. Spaced or open concrete blocks
work good. Backfilling with graded gravel will aid in restricting movement
of aquifer material.
The tank cover should be cast in place to insure a good fit. Forms
should be designed to allow for shrinkage of concrete and expansion of form
lumber. The cover should extend down over the top edge of the tank at
least 2 inches. The tank cover should be heavy enough so that it cannot be
dislodged by children and should be equipped for locking.
A drain pipe 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 the pipe should be screened to prevent
nesting by animals and insects.
The overflow is usually placed slightly below the maximum water-level
elevation. It should have a free discharge to a drain apron of rock to pre-
vent soil erosion at the point of overflow and should be screened.
The supply outlet should be located about 6 inches above the floor and
should be screened. Care should be taken to insure good bond between pipes
and the concrete structure.
7-3
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SANITARY PROTECTION
Springs may become contaminated when barnyards, sewers, septic tanks,
cesspools, or other sources of pollution are located on higher adjacent
land. In limestone formations, however, contaminated material may enter
the water-bearing strata through sink holes or other openings and may be
carried along with ground water for long distances.
The following precautionary measures will help to insure spring
water of a consistently high quality:
1. Provide for the diversion of surface drainage from the site. A
surface drainage ditch should be located uphill from the source so as to
intercept surface water runoff and carry it away from the source.
2. Construct a fence to prevent entry of livestock in the area
which contributes drainage to the water bearing strata and the spring
collection system.
3. Protect the spring collection system from human tampering by
fencing, locked covers, and warning signs.
4. Monitor the quality of the spring water. A marked increase in
turbidity or flow after a rainstorm is a good indication that surface runoff
is reaching the spring.
SPRING STORAGE SYSTEMS
Gravity Storage Systems
Spring sources are quite often located at elevations considerably
above the points of water use. If the elevation difference is sufficient
to provide adequate pressures (35 to 100 psi, 81 to 231 ft,) at the points
of consumption, a gravity supply system may be used. Since the storage
capacity of the spring collection chamber will generally not have sufficient
capacity to serve as an effective storage reservoir (except for very small
systems), water from the spring chamber may be piped to a conveniently
1-h
-------
located gravity storage reservoir. The spring flow should be sufficient to
meet the maximum daily water demands. The storage reservoir should have a minimum
capacity of one day's storage calculated on the basis of the average daily
demand (See Chapter 3).
Occasionally springs may require pumping to overcome elevation dif-
ferences. Properly sized centrifugal pumps may be used to pump water from
the spring basin and pump the water to a gravity reservoir placed at a
convenient location to provide gravity distribution. The pump may be con-
trolled by a float or pressure switch.
The design of separate gravity storage tanks (reservoirs) is discussed
in more detail in Chapter 6, Well Pump Systems.
Hydropneumatic Systems
Where gravity storage reservoirs are not possible or desirable, a
pressure pneumatic system may be used. The pump (usually a centrifugal
pump selected for the prevailing conditions) may draw water directly from the
spring collection chamber or a spring storage tank. The design details are
similar to that discussed in Chapter 6, the section on Hydropneumatic Systems.
DISINFECTION
Spring collection chambers should be disinfected prior to use. Deter-
mine the capacity of the spring chamber and storage tank. For each 100
gallons of capacity, the following quantities of chlorine disinfectant should
be added for a chlorine concentration of 200 mg/1 (ppm). Pre-mix the chlo-
rine compound in a pail of water and pour into the chamber or tank and mix.
Calcium Hypochlorite (HTH) Sodium Hypochlorite Bleach
70% Available Chlorine 5.25% Available Chlorine
Metric Units English Units Metric Units English Units
300 grams 4 ounces per 5 liters per 2 quarts per
per cubic 100 gallon cubic meter 100 gallons
meter of capacity capacity of capacity
capacity
7-5
-------
Mix and wash interior walls above the water level using a clean broom
or brush. Run water through the overflow and drain. Allow at least 2
hours of contact and then drain until the strong chlorine odor disappears.
The chlorine dose may be reduced to 100 mg/1 dose and the retention time
increased to 12 hours.
After disinfection and flushing to remove the chlorine, collect a
sample for coliform testing at an approved laboratory. If the results are
unsatisfactory, repeat the disinfection process until coliform tests are
acceptable.
7-6
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Figure 7-1: Spring Protection
Surface Water'.
Diversion
Ditch
Overflow
Valve & Box
Perforated Pipe-
PUN
Surface Water
Diversion Ditch
lock
Clay
Overflow,
Maximum Water level^lf!
Steps
¦Valve &
• : Box ~
jo Storage
Water-Bearing Gravel
Water Stop
Cleanout Drain
(Reproduced from EPA Manual of Individual Water Supply Systems,
Figure 10, Page 57)
7-7
-------
CHAPTER 8
DEVELOPING SURFACE WATERS
Streams-Lakes-Ponds-Reservoirs - Infiltration
Galleries - Storage Systems
SURFACE WATERS
Surface waters are exposed to both natural and man induced pollution.
Unlike properly developed ground waters which maintain a fairly constant
quality, surface waters vary greatly in quality depending upon natural and
man made events. Therefore, all surface water supplies require treatment
to a greater or lesser degree depending upon the circumstances. Invariably,
the treatment is more sophisticated than with ground waters and requires
more diligent operation and maintenance and more costs. Also, the legal
aspects involving surface water rights must be carefully considered. A
professional engineer should be engaged to plan and design surface water
sources.
Notwithstanding, there are occasions when the use of surface waters
for a small water supply is unavoidable due to the poor quality of local
ground water or the lack of adequate ground water. Under these conditions,
surface supplies may be considered. Because of the more detailed require-
ments which must be met, it is advisable to consult with State authorities
early in the considerations.
Other factors being equal, impoundments including lakes, ponds,
reservoirs, etc. are preferred over streams as the quality of the water is
usually less variable, reducing the extremes in quality. Treatment facili-
ties may then be designed for these less extremes, thus reducing the
sophistication of treatment and costs.
8-1
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As described in Chapter 2, a complete sanitary survey of the pertinent
part of the watershed must be made before proceeding with the design.
Assuming that the sanitary survey shows favorable conditions and the source
will provide an adequate quantity of water to meet needs, the required
treatment processes can be determined, after consultation with the State
agency. The design features related to the development of the source itself
should include:
- Intake structure and screens.
- Pump stations or gravity flow (whichever is appropriate) to the
treatment plant.
- Treatment plant design. Filtration, most likely preceded by
pre-conditioning, and chlorination are usually necessary.
- Treated water storage, pumping facilities and distribution storage,
as needed.
- Chemical storage, as needed.
- Waste water disposal as required by the State agency.
- Plant operating procedures and operating reports and records.
- Sampling and testing, including on-site laboratory facilities for
treatment plant operation control.
- Qualification of operators (consult State authorities for requirements).
- Metering devices as appropriate.
Pre-packaged treatment units are available and are often suited for
small surface water supplies. Some are highly automated and may reduce
(but not eliminate) the need for manual operation.
3-2
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INFILTRATION GALLERIES
Recreational or other developments located in the mountains may have
access to a head water mountain stream where the watershed is generally heavily
forested and uninhabited by man. However, following periods of heavy rainfall
or spring thaws, debris and turbidity may cause problems at the water intake
and will materially increase the required degree of treatment. If the con-
ditions 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.
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.
A typical installation generally involves the construction of an under-
drained, sand filter trench located parallel to the stream bed and about 10
feet from the high water mark. The sand filter is usually located in a
trench with a minimum width of 30 inches and a depth of about 10 feet,
sufficient to intercept the water table. At the bottom of the trench, per-
forated or open joint tile is laid in a bed of gravel about 12 inches in
thickness, with about 4 inches of graded gravel located over the tile to
support the sand. The embedded tile is then covered with clean, coarse sand
to a minimum depth of 24 inches, and the remainder of the trench 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. Chlorination will be necessary
and may be done in the chamber or at another place, but prior to any use.
Where soil formations adjoining a stream are unfavorable for the loca-
tion of an infiltration gallery, the debris and turbidity which may be
occasionally encountered in a mountain stream may be controlled by con-
structing a modified infiltration gallery, constructed in the stream bed.
8-3
-------
If a natural pool is not available in the stream bed, it will be necessary
to construct a dam 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 llie 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 where the water is diverted to chlorination facilities.
RAW WATER STORAGE
Surface water sources are often located at higher elevations which may
permit gravity storage and distribution to the points of consumption. Where
these conditions exist, a gravity system may be used.
If the surface water source has a safe yield equal to at least the
maximum daily demand, a raw water (water prior to treatment) reservoir may
not be necessary. A large lake or impoundment used as a small water supply
source usually has sufficient storage to meet daily needs. However, an
analysis should be made to remove any doubt.
If the surface water source cannot meet maximum day demands, a raw water
reservoir must be provided. The reservoir should have sufficient capacity to
insure maximum daily demands during dry periods. A detailed analysis is
necessary to determine the proper capacity.
Surface water sources may require pumping to overcome elevation dif-
ferences. Centrifugal pumps are often used to pump water from the intake
structure to the treatment plant.
8-4
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TREATMENT
Surface waters must be treated. Consult the State agency for require-
ments (also see Chapters 9 (Chlorination) and Chapter 10 (Treatment and
Conditioning).
The treated water storage and distribution design is essentially the same
as described in Chapter 6, Hydropneumatic and Gravity Storage Systems, and
Chapter 11, Distribution System.
8-5
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CHAPTER 9
CHLORINATION
Chlorination Principles - Terminology - Influencing Factors
Contact Time - Chlorinator Capacity - Preparing Stock
Solutions - Residual Tests
INTRODUCTIONS
Micro-organisms are ever present in the environment. Since water is a
product of the environment, it must be considered to be contaminated unless
a series of biological tests prove otherwise. By no means are all micro-
organisms in the water environment harmful to people, but some are pathogenic
(disease producing), particularly those associated with the intestinal
discharges of man or animals infected with enteric (intestinal; diseases.
Pollution by sewage is by far the greatest risk but animal wastes cannot be
discounted. Surface waters are highly susceptible to pollution and the
normal "cleansing action" of streams and impoundments cannot be relied upon
to rid the water of these pathogens. Ground waters are also subject to
pollution from subsurface sewage disposal systems and leaking sewers. How-
ever, the cleansing action of water moving slowly through soil and some rock
formations does have a significant affect in straining and eliminating
pathogens and coliform organismsin general. Therefore many well supplies,
after thorough testing, may be used without disinfection. Surface waters
must always be disinfected before public use. The prudent water purveyor
will always provide disinfection, even^-if not required by the State agency.
(1) See explanation and significance of coliform organisms in Chapters 1 and 11.
9-1
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Disinfection is the process of destroying a large portion of the
micro-organisms in water with the probability that all pathogenic bacteria
are killed in the process. In water treatment, disinfection is almost
always accomplished by adding chlorine or chlorine compounds. The practice
is so effective and has such wide acceptance that the term "chlorination" is
used synonymously with disinfection. Without a doubt chlorination is the
most widely practiced unit treatment process, and for good reason. Disinfec-
tion is often required by State agencies where the water is of questionable
bacteriological quality or where there is a potential for contamination.
In other instances, the water purveyor may wish to provide disinfection as
a measure to reduce risks, increase reliability, control growths in the
system, oxidize odors and taste producing substances and provide a residual
protection against inadvertent contamination within the distribution system.
The cost of effective chlorination is surprisingly modest compared to the
advantages. It is highly recommended that every public water system be con-
tinuously disinfected.
A number of chemicals and methods are available for disinfection, but
none have achieved the success of chlorination. If the water purveyor
wishes to consider other methods, the State agency should be consulted.
The interested reader is referred to the American Water Works Association
publication entitled "Water Quality and Treatment" for further discussion
on the advantages and limitations of disinfectants other than chlorine.
CHLORINATION METHODS
Chlorine may be applied by two basic methods: (1) gas chlorination
employing compressed chlorine gas or (2) hypochlorination employing a
chemical feed pump to inject a water solution of chlorine compounds.
9-2
-------
Gas Chlorination
Chlorine gas is available in compressed liquid form stored in steel
pressurized cylinders, generally available in 100 lbs., 150 lbs. and ton
containers. A gas chlorinator must be employed to meter the gas flow
and mix it with water which is then injected as a water solution of pure
chlorine. Small water supplies can effectively handle the 100 or 150 lb.
container but the larger containers are not recommended for small systems
as special hoists and cradles are required for handling. Chlorine gas is
a highly toxic lung irritant and special facilities are required for
storing and housing gas chlorinators. Chlorine gas dealers and chlorinator
manufacturers will supply details. The advantage of this method is the
convenience afforded by a relatively large quantity of chlorine available
for continuous operation for several days or weeks without the need for
mixing chemicals. Gas chlorinators have an advantage where variable water
flow rates are encountered as they may be syncronized to feed variable
rates of chlorine feed. Capital costs are somewhat greater but chemical
costs may be less.
Although gas chlorination is used extensively in larger water systems,
most small system operators will find the use of chlorine compounds mixed
with water and fed into the system with inexpensive hypochlorinators,
completely satisfactory. Gas chlorinators require special safety precau-
tions and should not be used until the plans of a facility are approved by
the State agency. (Suggested reference, Safety Practices for Water Utilities-M3,
American Water Works Association, Reference No. 33.)
9-3
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Hypochlorination
Chlorine compounds come in a variety of forms. They are readily
available throughout the country because of their common household and
swimming pool use.
- Chlorine solutions of sodium hypochlorite (NaOCl), are available
as 5.25% chlorine (common household chlorine bleach) and 15%
solutions available in 5 gallon carboys and larger quantities.
- 1 gallon of 5.25% contains 0.42 lbs. of available chlorine
- 1 gallon of 15% contains 1.25 lbs. of available chlorine
The chlorine solution mixes easily with water to make stock water
solutions of the desired strength.
- Granular form as high test calcium hypochlorite containing 65-70%
available chlorine, commonly marketed as HTH, PitChlor, Perchloron,
etc.
The dry forms of chlorine require mixing with water to make a stock
solution of the desired strength. Mixing is somewhat tedious and
precipitates of calcium salts in the stock solution and chemical
feeder requires regular maintenance. The dry forms can be stored
for considerable periods in the original container, in cool dry
places.
The water solutions of either the liquid or granular dry forms are
prepared in predetermined stock solution strengths and are injected into
the water supply using special chemical metering pumps called hypochlori-
nators. The positive displacement types are highly accurate and reliable
and are preferred over hypochlorinators employing other feeding principals,
usually based on a suction principal. Because these latter units are not
accurate and reliable, State agencies generally do not approve their use
where disinfection is required to insure a safe water.
9-4
-------
Positive displacement type hypochlorinators are readily available
from water conditioner suppliers at relative modest costs. These small
chemical feed pumps are designed to pump (inject under pressure) an
aqueous solution of chlorine into the water system. They are designed to
operate against pressures as high as 100 psi but may also be used to Inject
chlorine solutions at atmospheric or negative head (suction side of water
pump) conditions. In the latter cases, anti-siphon devices are necessary
(usually built into the unit). Hypochlorinators come in various capacities
ranging from 1.0 to 60 or more gallons per 24 hours. Most manufacturers make
an intermediate range unit adjustable from 1 to about 24 gallons per 24 hours.
This size is usually adequate for small systems.
The pumping rate is usually manually adjusted by varying the stroke of
the piston or diaphragm. Once the stroke is set, the hypochlorinator feeds
accurately at that rate, maintaining a constant dose. This works effectively
if the water supply rate is fairly constant, as with the output of a pump.
If the water supply rate varies considerably, a metering device^^may be used
to vary the hypochlorinator feed rate syncronized with the water rate. Where
a well pump is used, the hypochlorinator is connected electrically with the
on-off controls of the pump. If two or more wells are designed to operate
independently, a hypochlorinator may be required for each pump output.
Figure 9-1 shows a typical setup with one well pump.
In instances where chlorination is required by the State agency, spare
repair kits and preferrably a standby hypochlorinator should be available
at all times.
(1) Metering devices are available to vary the feed rate of both electrically
powered and water powered hypochlorinators. The latter may be used where
electric power is not available at the chlorination site.
9-5
-------
Figure 9-1: Typical Hypochlorinator Installation
CHEMICAL
SOLUTION
PUMP
MANUAL
VALVE
WELL
PUMP
TO*-
CHECK
VALVE
CHEMICAL
SOLUTION
CONTAINER
FROM
WELL
PRESSURE
TANK
CHLORINATION TERMINOLOGY
Regardless of the form of chlorination, chlorine gas or chlorine com-
pounds, the reaction in water is basically the same. The standard terra for
the chlorine concentration is either milligrams per liter (mg/1) or parts
per million (ppm). The latter seems to be more acceptable to water plant
operators and will be used in the. discussion that follows:
1. Chlorine Fed or Dose: The total amount of chlorine fed iato the water
system by the chlorinator.
- With gas chlorination, the dose is often expressed as pounds of
chlorine per day as measured with weight scales which show che
daily loss in weight of the chlorine cylinder. The pounds per
day dose may be converted to ppm as follows:
ppm = lbs, chlorine fed/day x 83 or lbs, chlorine fed/day x 5000
gallons per minute gallons per hour
- When chlorine compounds are injected as a water solution by means
of a hypochlorinator, the number of gallons of stock solution fed
per day is recorded. The solution strength is usually expressed
as a percentage of chlorine or simply the number of gallons of
chlorine bleach (%) per gallon of water to make up the stock solution.
9-6
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2. Chlorine Demand: Chlorine is a very active chemical oxidizing agent.
When injected into water, it combines readily with certain inorganic
substances which are oxidizable (hydrogen sulfide, nitrites, ferrous
iron, etc.) and with organic impurities including micro-organisms and
their decay products. These reactions consume or use up some of the
chlorine before it can fully destroy micro-organisms. This amount used
up is the chlorine demand.
Chlorine Demand = Chlorine Dose - Chlorine Residual
3. Chlorine Residual is the amount of chlorine (by test) present in the
water after the chlorine demand is satisfied. The presence of a "free"
(2)
residual of at least 0.2 - 0.4 ppm (in relatively unpolluted, low
turbidity water) after the chlorine demand is satisfied, usually provides
a high degree of assurance that the disinfection of the water is complete.
However, several other factors must be considered, including the factors
discussed on page 9-11.
A free residual also provides some protection against any chance con-
tamination which may inadvertently enter the system. The chlorine resi-
dual test sample is usually collected before the first point in the
distribution system where water is consumed. However, it is also advis-
able to take the test at the furthest point in the system to insure that
a residual exists throughout the whole system. The residual test is the
basis for increasing or decreasing the chlorinator feed rate to achieve
the desired value. Too much chlorine residual will be offensive to some
consumers.
Chlorine Residual = Chlorine Dose - Chlorine Demand
(2) See Table 9-1.
9-7
-------
Chlorine Contact Time: The contact time is the time interval (usuaJly
minutes) 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 is required for the disinfecting
action to become completed. The minimum required time depends on severaJ
factors.
(a) The chemical form of the available chlorine residual (See
Item 5). "Free available chlorine" is faster acting than
"combined chlorine."
(b) The magnitude of the residual - The higher the residual, the
more active and faster the disinfection.
(c) The pH of the water - The higher the pH, the longer the time
required.
(d) Water temperature - The lower the temperature, the longer the
contact time required.
The contact time is usually a fixed condition dependent upon the rate
of flow of the water and the time it takes the water to pass through the
piping and storage facilities. Generally speaking, it is preferrable
that the contact period be not less than 30 minutes, under the peak
demand flow conditions. However, even more may be necessary under
unfavorable conditions. Under those conditions it may be necessary to
add a contact tank of sufficient capacity to provide the necessary
contact time. Consult the State agency for further advise.
Chemical Forms of Chlorine Residual: Most waters contain some organic
matter and the products of organic matter decay, particularly ammonium
compounds, more so for surface waters but also true of ground waters.
They may be of recent time origin or have an origin in the distant past
history of the water. These compounds react with chlorine and often
9-8
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form so-called "combined chlorine," including chloramines (ammonia
compounds plus chlorine). These combined forms of chlorine are more
or less weak disinfectants and they may show up as chlorine residual
in some testing procedures. The excess chlorine (over and above that
combined with ammonia or organics) is called "free available chlorine"
and is a highly desirable, active disinfectant. The "total chlorine
residual" is the sum of the combined plus free chlorine.
Total chlorine residual = combined + free chlorine
These various chemical forms of chlorine residual can be distinguished
by tests.
FACTORS INFLUENCING CHLORINATION PRACTICE
1. Suspended matter (turbidity) may shield bacteria from the action of
chlorine. Therefore other factors being equal, chlorination is more
effective in low turbidity waters.
2. Organic matter reacts with and consumes chlorine to form weak disin-
fectants, which may not be effective.
3. Ammonia reacts with chlorine to form a chlorine compound having lower
disinfecting qualities than free chlorine itself.
A. The pH value. Waters having pH values less than about 7.2 are more
effectively disinfected than higher (alkaline) pH values. (See Table 9-1).
5. Nitrites react with and chemically remove free chlorine. Thus, more
chlorine is needed to insure disinfection.
6. Hydrogen sulfide, a malodorous gas sometimes found in water, also
reacts with and consumes chlorine.
7. Iron and manganese when in the reduced dissolved state also reacts with
and consumes chlorine, increasing the chlorine dose required for disin-
fecting purposes.
8. Temperature. The higher the temperature, the more effective the dj sinfe.< Hon.
9-9
-------
9. Contact time. The longer the time, the more effective the disinfection.
10. Type of chlorine residual. Free chlorine is much more effective as a
disinfectant than combined chlorine.
11. Chlorine concentration. The higher the concentration, the more effec-
tive the disinfection and the faster the disinfection rate.
Table 9-1: Recommended Minimum Concentrations of Free Chlorine Residual
pH Value
Minimum Concentration of Free
Chlorine Residual, Contact Time
at least 30 minutes.
6.0
0.20 mg/1
7.0
0.20
8.0
0.40
9.0
0.80
10.0
0.80
The above table shows the very significant effect of the pH value on the
amount of chlorine residual required for effective disinfection.
CHLORINATOR CAPACITY
The chlorinator should be sized for the maximum expected conditions,
but should also be capable of handling minimum conditions. The capacity of
a gas chlorinator is often expressed in pounds of chlorine per 24 hours of
operation. Hypochlorinatoirs are usually rated in gallons of solution which
can be pumped (injected) per 24 hours of operation. Both types of chlorina-
tors can b£ regulated over a considerable practical range below the maximum.
The stock solution bLrength of hypolchlorinators may also be vancd to cover
a wide range of conditions.
9-10
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Gas chlorinators rated at 10 pounds of chlorine per day are capable
of chlorinating over a million gallons per day at a 1.0 ppm (mg/1) chlorine
dose. This is more than adequate for most small systems. It may be diffi-
cult to obtain a gas chlorinator to meet the low flow conditions of some
small water systems, another reason to consider the hypochlorinator for
most installations.
Positive displacement hypochlorinators with an adjustable output range
of 1.0"to about 24 gallons per 24 hours of operation will effectively handle
just about any dose range encountered in small water systems. Larger and
smaller units are available.
DETERMINING HYPOCHLORINATOR FEED RATE AND SOLUTION STRENGTH
In order to simplify the initial determination of a hypochlorinator
feed rate and the chlorine solution strength to achieve disinfection, a
dose rate of 1.0 ppm (mg/1) may be tried as a practical starting point.
This dose rate is usually adequate for most situations, particularly as a
first trial. With this assumption, the chlorinator setting and solution
I
strength may be determined for chlorine bleach solutions (5.25%) by using
Figure 9-2.
Procedure Using Figure 9-2 (5.25% chlorine bleach)
1. Assume dose rate of 1.0 ppm (1.0 mg/1)
2. Determine well puinp capacity (or other source flow rate) in gallons per
hour. If two or more well pumps operate independently, and sometimes
together, each may require a separate hypochlorinator setup. Make
separate calculations for each if the pump capacities are different.
3. Figure 9-2 has 3 scales.
- The scale on the righc is the water pump capacity in gallons
per hour.
<)-]!
-------
- The scale on the left is the hypochlorinator (chemical pump) feed
rate for a 1.0 ppm dose. It is also the amount of solution that
will be used if the system is pumped continuously for a full 24
hours, highly unlikely.
- The center scale is the number of gallons, quarts or ounces of
5.25% bleach which must be added to make each 5 gallons of solution.
As a first trial, assume a setting for the hypochlorinator at
about the midrange scale of the unit. This will permit adjust-
ments up or down the scale as necessary.
To use Figure 9-2, place a ruler at the proper well pump capacity (gph)
and the mid-range scale of the hypochlorinator and draw a light line.
The point where this line crosses the center scale, represents the
amount of bleach necessary to prepare 5 gallons of solution of Lne
proper strength to insure a 1.0 ppm dose.
Determine the number of hours that the well pump will operate in an
average day. An electric clock (with compatible voltage) may be con-
nected to the pump circuit as a simple means of determining this. If
the well pump operates for 6 hours a day, the hypochlorinator will feed
6/24 or 1/4 of the amount indicated in gallons per day.
After the initial setting, determine the actual chlorine residuals by
tests and compare with those shown in Table 9-2. If they compare
favorably, the settings are about right. If not, try adjustments of
the chlorinator settings or change the solution strength.
9-12
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Coliform bacteria tests should be made to insure satisfactory disinfection.
Example:
Given: - Well pump capacity = 6000 gallon per hour (100 gpm)
- Well pump operates 6 hours per day
- Hypochlorinator setting = 10
Solution: From Figure 9-2, it will take 1.0 gallons of 5.25% bleach added
to every 4.0 gallons of water to produce 5.0 gallons of solution
of the proper strength to dose at 1.0 ppm. If the well pump
operates for 6 hours per day, 6/24 x 10 = 2.5 gallons of solution
will be used per day, or 17.5 gallons per week. A 20 gallon solu-
tion tank will last for a week, which is a convenient and saLis-
factory arrangement.
Figure 9-2: Determining Required Amount of 5.25% Bleach to Make Solution
for 1.0 PPM Feed Rate for Hypochlorinators.
3
6
7
e
9
10
— IS
— 30
— 40
50
60
70
60
90
100
>-
<
o
<
o
<
cr
a.
2
3
a.
<
0
1
id
X
o
— 130
^ 200
CHEMICAL PUMP
3 -
z
4 -
o
3 -
.J
2 -
<
o
1 _
CO
— 3 -
H
=- 1300
6
o
—
4
— 1000
3 —
—
— 800
— 600
— 300
— 400
— 300
— 200
WELL PUMP
Mi
2
Source: Bruner-Calgon Water Treatment Equipment, by permission.
9-13
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TESTING FOR CHLORINE RESIDUALS
The amount of chlorine remaining in the water system (chlorine
residual) is determined by a relatively simple test commonly called the
DPD colorimetric test, short for the chemical name Diethyl-p-phenylene-diemine.
The test may be done under "field" conditions using pill reagents which are
placed in a special test tube provided with DPD kits. The presence of free
chlorine residual produces a violet coloi? which is compared with celor standards
to determine the quantity present. The kits are readily available from firms
which specialize in the manufacture of water testing materials. A combina-
tion DPD chlorine and pH kit is available and Is a worthwhile investment at a
modest price. The State agency will supply a list of acceptable kits on
request.
The tests must be made at least daily at a point in the system repre-
sentative of the full required contact time. A residual at the extreme end
of the system will assure that the chlorine residual remains in the entire
system in effective amounts. This will provide good assurance that the system
water is properly disinfected and will reduce the possiblity of slime growths
in the system.
Excessive chlorine residuals may be objectionable to consumers. Resi-
duals of 0,75 ppm or less are not,usually objectionable. Regardless, the
operator must adjust the chlorine feed to achieve effective disinfection as
the primary consideration.
9-14
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CHAPTER 10
TREATEMENT AND CONDITIONING
Softening - Iron and Mangenese Control - Other
Ion Exchange Systems - Taste and Odors -
Corrosion Control - Color - Turbidity
INTRODUCTION
Depending on the source, ground waters may often be used without
treatment. Nevertheless, chlorination for disinfection is always jusLifjed
Due to the nature of surface waters, they will almost always require treat-
ment, including chlorination.
Impurities in natural waters depend largely on the source and its
past history. Water destined for a ground aquifer picks up impurities as
it seeps through soil and rock, including possible sewage pollution. Onlak
of minerals is common. The natural straining action is significant in
removing particulate matter and this combined with the relatively long
retention period in the ground, has a significant effect in removing micro-
organisms. Ground waters have a fairly stable quality usually not nighly
affected by season changes.
Surface waters, on the other hand, are highly affected by land run-off
and natural pollution from the land including organic debris, clays and
silts. The potential for sewage and other waste pollution is ever present.
Therefore, the quality of surface water is highly variable depending upon
a host of factors.
The purpose of water treatment is to condition, modify or remove
undesirable impurities to obtain a water which is safe, palatable and
acceptable to consumers. Those impurities which are considered important
(1) See Chapter 9, Chlorination.
10-1
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to the health of consumers are specified in the National Primary Drinking
(2)
Water Regulations with maximum contaminate levels. If these contami-
nates are present in excess of the established limits, the water must
be treated or modified to reduce the levels. Those impurities which effect
theaesthetic qualities of the water are listed in the Secondary Drinking
Water Regulations as guidelines. Treatment or modification of the water
to achieve these desirable levels is highly recommended. Individual State
agencies may establish maximum permissible levels.
The U.S. Environmental Protection Agency has commissioned a study
on the "State-of-the Art of Small Water Treatment Systems." The
report provides valuable assistance in evaluating the various methods of
removing or reducing impurities in water supplies serving small public
systems and the costs. This publication is available through the U.S.
Government Printing Office. Consult the State agencies for further infor-
mation.
The information on water treatment and conditioning in this Chapter
is rather general and is designed to provide the water purveyor with the
basic understanding of equipment and methods of treatment which are com-
monly available. Several water treatment and conditioning equipment firms
produce a wide variety of equipment applicable to small public water systems,
and a wide choice of equipment and processes are available. Some manufac-
turers provide related engineering service. Professional engineers should
be consulted for further advice.
Chlorination for disinfection is the most widely practiced treatment
process and is covered in some detail in Chapter 9.
(2) See Chapter 12.
10-2
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Surface waters of highly variable quality require extensive treatment
including coagulation, sedimentation, filtration and chlorination. These
treatment plants must be custom designed for the prevailing conditions by
skilled design engineers. Skilled operators are required for operation and
maintenance to meet the day to day (sometimes hour to hour) conditions of
the raw surface water. Surface water supplies should only be considered
after consulting the State agency.
Listed below are the common "contaminate groupings" which influence
the quality of water and which may require treatment, removal or conditloiung.
The contaminates in each group are often treated by the same or similar unit
processes. However, treatment to control one grouping may also improve
another grouping.
1. Micro-organisms which will affect the sanitary quality--usua11v of
•i . (3)
human or animal origin.
2. Inorganic and organic contaminates for which maximum permissible
(3)
limits have been established , and others for which guideline
(A)
limits have been set.
3. Particulate matter^ and color^ which may affect the saniLarv
quality and the physical appearance—including soil, insolubJe
minerals, organic leachates, and certain aquatic organisms.
(4)
A. Substances which impart tastes and odors including hydrogen
sulfide, high concentrations of minerals, organic substances and
certain micro-organisms.
5. Minerals which produce hardness and scales (calcium and magnesium
(4)
salts) or stains (iron and manganese salts).
6. A combination of chemical factors which result in corrosion and
(4)
red water problems.
(3) Primary Drinking Water Regulations, Chapter 12.
(A) Secondary Drinking Water Guidelines, Chapter 12.
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CHEMICAL, PHYSICAL AND BACTERIOLOGICAL EXAMINATION TO HELP ESTABLISH
TREATMENT REQUIREMENTS
Early in the source development phase, representative samples of water
should be collected for a complete bacteriological, chemical and physical
examination at an approved water laboratory. Collection should be done in
accordance with techniques furnished by the laboratory. The required tests
may vary in different States based upon local experience but will generally
include those Primary Contaminates listed as a requirement for the type of
water system in question (see page 12-4 for a summary) and those Secondary
Contaminates listed on page 12-22 which are specified by the State agency.
Although not lised, the alkalinity and hardness of the water should also
be determined.
A complete interpretation of the results should be obtained from the
laboratory or others qualified to make the interpretations. The results
will determine the necessary treatment of the water and the limitations on
the use of the water, if any.
WATER SOFTENING
Well waters often exhibit hardness characteristics as a result of
dissolved calcium and magnesium salts. Water softening is the process of
removing some of the calcium and magnesium. Softening of hard water is
desirable if:
1. Excessive amounts of soap are needed to produce a lather.
2. Hard scale is formed on cooking utensils or laundry basins.
3. Hard, chalklike formations coat the interiors of piping or
water tanks.
4. Heat-transfer efficiency through walls of hot water heaters or
heat exchange units is reduced.
10-4
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No specific limits have been established for hardness but the fol-
lowing guidelines may be helpful: Soft water - less than 75 mg/1 as
calcium carbonate; Moderately soft or moderately hard - 75-150 mg/1;
Hard - 150-200 mg/1; Very hard - over 200 mg/1.
The buildup of scale will cause an appreciable reduction in pipe
capacities and pressures. The appearance of excessive scale from hard
waters will also be aesthetically objectionable. Water hardness can be of
two general types. One type, called carbonate hardness, is due to Lhe
bicarbonates of calcium and magnesium; the other type, called noncarbonaLe
hardness, is due to salts of calcium and magnesium other than bicarbonate,
usually chlorides and sulfates.
Softening or hardness removal can be accomplished by any method which
will remove calcium and magnesium. Two major softening methods are used:
(1) chemical precipitation (Lime-Soda Ash Process), and (2) Ion exchange.
Both processes increase the sodium content of the w£ter which may make it
undesirable for people on a low-sodium diet.
Lime-Soda Ash Process
The use of the lime-soda process is not practical for a small water
supply system.
Ion Exchange Process
The ion exchange method is particularly suitable for small water
systems. The cylinderical units take up little space and operate under
normal system pressures. No double pumping is necessary. The units
remove both forms of hardness. Most units will tolerate up' to 4 rag/1
of iron and manganese or hydrogen sulfide in the water but manufacturers
should be consulted for advice.
10-5
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Softening by ion exchange removes calcium and magnesium ions by
exchanging or replacing them with other ions such as sodium. Since these
ions all have a positive charge, they are called "cations" and this ion
exchange process is often called "cation exchange."
Removal of hardness by cation exchange is effective only as long as
sodium is left on the exchange media (resin). When the sodium is all used
up, it is necessary to regenerate the resin. The regeneration may be done
manually or automatically. The steps are as follows:
Backwashing is the first step of the regeneration process. Clean
water is forced through the bed in reverse direction at rates of 5 to 7
gpm/sq. ft. for about 10 minutes to remove any accumulated dirt and to
loosen and regrade the resin material to prevent packing and channeling in
subsequent re-use.
A strong brine solution is then forced through the exchange unit.
This reverses the exchange reaction, and sodium from the brine displaces
the accumulation of calcium and magnesium attached to the exchange media.
Rinse water is then flushed through the unit to remove the calcium
and magnesium and the excess brine. The rinse water is wasted tc a sewer.
The entire regeneration process takes about one hour. Fully automatic
units are available. Two or more units may operate in parallel to maintain
a continuous flow of treated water. Regenerations may be staggered so that
only one unit at a time is off the line. The softened water has little
hardness but has increased sodium content. Total solids are not reduced
by sodium cycle softening.
Water from the cation exchanger will have practically zero hardness
until the exchange capacity is approached. Since a water withouL hardness
is corrosive, the exchanger water may be blended with bypassed water to pro-
duce a resultant water of desirable hardness, usually between 70 and 100 ppm.
10-6
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Water from the cation exchanger should be tested and when the hardness
increases, the unit needs to be regenerated. Some units have sensors and
regenerate automatically. The approximate interval between regenerations
i
may also be calculated if the following are known and a water meter is.
available: natural water hardness, volume of exchanger media in cubic
feet, and softening capacity per cubic feet. For example:
Raw water hardness = 170 ppm or 10 grains/gallon
(1 grain/gal. = 17.1 ppm)
Softening capacity - 5000 grains/cubic feet (manufacturers specification)
Volume of medium - 50 cubic feet
Total hardness removed between regenerations = 50 x 5000 = 250,000 grains
Volume of water treated between regenerations2 250,000 = 25,000 gallons
10
Therefore, the unit must be regenerated after conditioning about
25,000 gallons of water.
IRON AND MANGANESE CONTROL
Iron and manganese problems are more common in well supplies than in
surface supplies. They are common constituents in many soils and rocks, in
varying quantities. Iron and manganese may be objectionable in concentra-
tions greater than 0.3 mg/1 and 0.05 mg/1, respectively. They cause stains
in laundered clothes and fixture surfaces. When the iron content of water
is high, tea or coffee may turn dark (like ink) and the taste is impaired.
Iron problems may also occur as a result of corrosion of iron pipes in
the distribution system. If this occurs, the water may be treated to make
it less corrosive. (See the Section on Corrosion Control.) Slime growths
of iron bacteria may aggravate the situation.
Although several processes are available for iron and manganese removal,
the ion exchange method is perhaps the most applicable to small water systems.
Most softening units are capable of removing small amounts, but it is best
to employ special ion exchange resins designed for iron and manganese.
10-7
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Iron Stabilization - Iron in the soluble form may be stabilized or
sequestered by adding polyphosphates or organic sequestering agents. Sodium
hexametaphosphates at dosages of about 5 mg per mg of iron may be used for
this purpose. While this treatement will stabilize iron and manganese in
suspension, it may not be suitable where iron concentrations of 1 mg/1 are
exceeded. Moreover, when the water is heated, the polyphosphate will lose
its stabilizing properties. The application of the polyphosphate must take
place ahead of any aeration or chlorination, otherwise it will not be
effective.
Polyphosphate dosages should be limited to less than 10.0 mg/1, because
excess phosphorous may stimulate bacterial slime growths in distribution
systems. Chlorination, following the addition of polyphosphates, will
help control these growths. Polyphosphates may be mixed with water and fed
into the system by means of a hypochlorinator type chemical feeder. Manu-
facturers of polyphosphates and the State agency should be consulted for
details.
Other Use of the Ion Exchange Resins and Adsorbents
Ion exchangers are quite versatile and have several other applications
in water conditioning, in addition to softening and iron and manganese
removal.
- Ion exchange resins may be used for partial demineralization to
reduce the total mineral content (total dissolved solids).
- Resins mixed with activated carbon are effective in controlling some
taste and odor problems including dechlorination (removal of chlorine)
where necessary. Activated carbon filters are also available for
greater effectiveness.
- If fluoride concentrates exceed maximum permissible limits, they may
be reduced with special activated bone char resins.
10-8
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- Organic adsorbents are capable of removing certain organic substances.
- Foaming substances, principally from household detergents, may also
be removed by carbon adsorption filters.
- Resins are available which will tolerate and remove low concentrations
of hydrogen sulfide gas.
TASTE AND ODOR CONTROL
Tastes and odors are aesthetically objectionable and in the case of
food establishments, etc., may have an economic impact from dissatisfied
customers. Taste and odors may be natural to the water (hydrogen sulfide
gas, the rotten egg odor; iron and manganese, etc.) or may result from
man-made contamination of chemical or sewage origin.
If the cause of the taste and odor can be determined, a specific treat-
ment may be designed. Hydrogen sulfide may be removed by chlorination which
converts (oxidizes) the odorous gas to free sulfur. The free sulfur has
practically no taste but may make the water cloudy (milky color) . If so,
filtration may also be indicated. Sufficient chlorine must be added to not
only react completely with the hydrogen sulfide, but also to produce a resi-
dual which will be effective as a disinfectant. Some ion exchange filters
are also effective.
The tastes resulting from iron or manganese may be removed by ion
exchange units as previously discussed.
Activated carbon filters (or resins mixed with activated carbon) are
often effective in removing taste and odors attributed to some chemicals
or organic decay tastes. Carbon filters will also remove chlorine tastes
if this is objectionable for some special reason. It is, however, highly
desirable that the water has a measurable residual throughout the system for
safety purposes (See Chapter 9).
10-9
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CORROSION CONTROL
Corrosivity is a complex characteristic of water related to pH,
alkalinity, dissolved oxygen, total dissolved solids and other factors.
Water is said to be corrosive to a metal if it dissolves the metal
or furnishes substances that react with it at the metal-water Interface.
In the case of iron and copper, the dissolved metals often re-precipitates
to form reddish brown stains (red water) with iron and bluish-green stains
with copper. These have both aesthetic and economic significance. Corro-
sive water may also dissolve lead and cadmium and these have health
implications (See Chapter 12, Primary Regulations).
The effects of corrosive water are easily recognized but there is no
completely acceptable index for measuring the corrosivity. Nevertheless,
certain treatment and conditioning processes may be effective in reducing
the corrosive tendency of water in varying degrees. Where evidence exists
of red water problems (tuberculation or pitting of the interior of iron
pipes or other indicators) an evaluation should be made to determine pos-
sible effective remedial actions.
Although the discussion of corrosion in this chapter is limited to
the interior of metal pipes, tanks, etc., exterior metal surfaces may be
corroded by exposure to certain soils. The resulting corrosion may also
warrant remedial steps.
Figure 10-1 may be useful to assess the corrosivenes of water. The
Figure shows the relationship of pH and alkalinity and the conditions
which may result in reduced corrosion for a given water. To use the chart,
determine the pH and alkalinity of the water over a period of a few days.
From the curves, determine if the water falls within the zone of serious
corrosion or the intermediate corrosion zone. If so, corrosion control may
be necessary and a water engineer and the State agency should be consulted.
10-10
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Figure 10-1: Alkalinity and pH. Adapted from Water Supply Control,
New York Department of Health.
AeCurvc of Values Necessary lo Produce
a Coaling ol Ctoum Carbonate
B s Curve of Calcium Carbonate Equilibrium -
C ¦ Curve of Values Neceuary to Prevent
Iron Stains
> Intermediate Zones
of Possible Corrosion
Zone of
No Corrosion
Y/ Zone ol //,
Senous Corrosion
7Z
250
300
ISO
Maalimly. in Milligrams per liter
2G0
350
100
Factors Influencing Corrosion
The water characteristics which significantly influence the rate of
corrosion of a metal include (1) the amount of dissolved oxygen; (2) the
pH (hydrogen ion concentration); (3) the concentration of carbon dioxide;
(4) the absolute and relative concentrations of other inorganic ions in
the water, particularly calcium bicarbonate, chloride and sulfate; (5)
increasing the temperature tends to increase the speed of chemical reac-
tions in general; and (6) the velocity, i.e., the rate of flow of the
water past the metal surface governs the rate at which the dissolved oxygen
essential to corrosion is replenished at the metal surface.
Corrosion Control Methods
Corrosion control methods commonly used in waterworks practice include:
A. The choice of non-metallic materials or corrosion-resistant metals
in construction.
(1) Non-metallic materials include asbestos-cement and plastics.
(2) Corrosion-resistant metals such as aluminum, stainless
steel, nickel, silicon, copper, brass and bronze.
10-11
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B. The choice of metallic coatings, such as zinc (galvanizing) or
aluminum, to protect metals.
C. The choice of non-metallic coatings to protect metals. Appro-
priate materials include coal tar enamels (bituminous), asphaltics,
cement mortar, epoxy resins, vinyl resins and paints, coal
tar-epoxy enamels, inorganic zinc, silicate paints and organic
zinc paints. Consult the State agency for approved paints.
D. The choice of the chemical treatment process to reduce corrosion.
(1) Deposition of protective coating or film on the metals
by use of calcium carbonate, sodium hexametaphosphates
and silicates.
(2) Removal of oxygen (generally not practical).
(3) Removal of free CO^.
(4) pH adjustment.
E. Electrical Control (Cathodic Protection)
This process involves the application of a low voltage current
which flows through the water (usually m a steel water tank) so
that the external voltage renders the tank cathodic and concen-
trates corrosion on anodic metals which are designed to corrode,
instead of the tank.
Some proprietary water conditioning units are available which may be
applicable for small water systems. They are usually quite simple to
install, operate and maintain and may prove effective in some situations.
Manufacturers catalogs provide some details.
COLOR REMOVAL
Color in water may be indicative of dissolved organic materials such
as the leachate from woodlands and wetlands. Color can also be caused by
inorganic substances such as iron and manganese, previously discussed.
10-12
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Color becomes objectionable to most people when levels approach 15 color
units (C.U.) or more but may be detectable to the naked eye at about 5 C.U.
Organic color may also affect chlorination as the organic color combines
with chlorine to form chloro-organic compounds which uses up chlorine Co
form weak, disinfectants. Sufficient chlorine must be added to insure free
type residuals (See Chapter 9). The oxidation effect of chlorination may
assist in removal of color.
In larger water systems employing coagulation and filtration, color
is removed along with turbidity. However, small well supplies are limited
for practical reasons to less sophisticated treatment such as carbon pres-
sure filters and perhaps chlorination.
TURBIDITY REMOVAL
Properly developed well waters usually have turbidity levels below
the turbidity units listed as the maximum contaminate level in the
Primary Regulations (See Chapter 12). But occasionally, turbidity may
become a problem. Surface waters will normally require filtration treat-
ment to remove turbidity. Turbidity is suspended, visible matter, often
caused by silt or clay extracted from soil, insoluble minerals, and sus-
pended organic material including micro-organisms. These substances nave
the following significance:
1. Suspended solids may shield bacteria and thus reduce the reliabi-
lity of chlorine disinfection.
2. In well supplies, turbidity may be indicative of the entrance of
surface or shallow subsurface water and potential contamination.
3. In supplies employing filtration, it is indicative of inadequate
treatment.
10-13
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4. Turbidity may be the result of iron or manganese precipitates
(reddish brown or chocolate brown) in the distribution system,
either from the well source or from corrosion of the distribution
system (iron pipes). Lime deposits on pipes from hard water and
may subsequently flake off, resulting in turbidity.
5. Turbidity may be the result of sewage or other waste pollution,
particularly if it is also associated with increased coliform
bacteria counts.
6. Surface waters are highly susceptible to turbidity and will
require continuous treatment.
Where turbidity is present in the water at its source, filtration
(usually pre-conditioned by coagulation with alum or other coagulants and
subsequent settling) is the indicated treatment. If the turbidity is the
result of iron or manganese, the ion exchange system (previously des-
cribed) may be used. Hard water scaling may be controlled by ion exchange
softeners.
Small water systems may find the pressure sand (or other approved
media) filter effective. These filters operate under system pressure and
do not require double pumping. They are fabricated in both vertical and
horizontal cylinderical vessels. Flow rates of 2 to 3 gallons per square
foot are common. As the filter media becomes clogged, the pressure re-
quired to force water through it increases. At a pre-selected pressure
drop, the filter is backwashed by reversing the flow but at a rate of 3
to 5 times the filter rate. The backwash water is discharged to waste.
Care must be taken to avoid a cross-connection with a sewer (See Chapter
15). Activated carbon is> sometimes mixed as part of the filter media to
help remove tastes and odors. Pre-conditioning with coagulants may be
necessary.
10-14
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Diatomaceous earth filters are commonly used to clarify swimming pool
waters but are generally not acceptable for public water supplies where
turbidity is a significant problem. These filters rely on a filter cake
formed on rigid porous filter elements by feeding a water mixture of
diatomaceous earth. The process is not always reliable and the State
agency should be consulted before its use.
10-15
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CHAPTER 11
DISTRIBUTION SYSTEM
Pipe Sizing - Pipe Types - Accessories
Construction - Disinfection
INTRODUCTION
The distribution system, as the name implies, includes the network of
pipes, valves, fire hydrants, meters and other associate appurtenances.
Distribution storage reservoir and booster pumps are often included and
are discussed in Chapter 6. This Chapter discusses the basic elements
of the system design and construction.
The distribution system must be designed to meet the special condi-
tions of each water system. Small water supply systems will vary from
the single building establishment to the rather extensive system servicing
mobile home parks and small communities. There are no "packaged"
distribution systems. Each must be designed specially. Therefore, the
services of a consulting engineer are particularly important. Furthermore,
most of the distribution system is buried and replacement will be costly.
It should be designed and constructed to meet long range needs, up to 50
years. Poor quality materials and/or construction is not a wise investment.
Preliminary design data and decisions should include:
- Determination of water demands in the various segments of the
system. See Chapter 3 for discussion of water demands.
- Will fire flows for fire protection be provided? If so, the design
must take this into account.
- Determine the elevation differences throughout the service area
and the static head conditions. Assess the various options
available for pumping (or gravity flow) and storage in relation to
the head requirements.
1J-1
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- Assess the advantages and disadvantages of various piping materials
and select most appropriate pipe for the system conditions.
- Assess physical characteristics of soils, depth to rock and ground
water, required depth for frost protection, etc. Corrosive soils
may require special considerations and may affect the choice of pspe.
- The characteristics of the water may also affect the choice of pipe
and appurtenances. Water which tends to be corrosive to piping may
suggest the use of plastic or asbestos cement pipe.
SITE CONDITIONS
Prior to selecting pipe materials, consideration should be given to
the physical characterists of the soil as mentioned above. The assessment
should include anticipated unusual earth and surface loads on the pipe as
these loads will affect pipe selection. Local soil survey publications
will be helpful in identifying soil types, characteristics and limitations.
Consult the local Soil Conservation Service agent for information and
advice. Unstable conditions may warrant special means of support.
Clay soils in some areas are severely affected by extremes of wetness
and dryness, and are subjected to extraordinary shrinkage on drying. This
shrinkage usually results in deep cracks in the earth's surface and may
result in damage to underground structures, including pipe materials. The
clay forms a tight gripping bond with the pipe structure, subjecting it to
severe stresses as the clay shrinks. In such situations it is good engine-
ering practice to bed the pipe in an envelope of several inches of tamped
sand.
The depth of frost penetration will determine the minimum depth of
the pipe below ground surface. Accepted local experience should be prac-
ticed. Ground water within the pipe trench will increase the cost of
construction.
11-2
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SELECTION OF PIPE SIZES
Selection of adequate piping sizes is important to insure an adequate
supply of water to the consumers at satisfactory pressures. If the piping
is undersized, large head losses will result with a corresponding reduction
in water flow, reduced pressure, and an increased potential for inadvertent
back siphonage from cross-connections. See Chapter 15.
A water distribution network analysis must be performed to determine
proper pipe sizes for new systems or to evaluate the adequacy of an existing
system. Before performing the analysis, the designer must determine the
water demands throughout the system (See Chapter 3). These data, together
with data on the elevation of the various components and the pressure require-
ments, will enable the engineer to perform the analysis.
It is a relatively simple process to determine the required pipe size
for a single pipe conveying water between two points. The process becomes
more complex as the single pipe becomes a network of pipes. It is not
within the scope of this manual to provide the reader with sufficient
technical information to perform the complex analysis. That is a job for
the professional engineer. The information that follows will provide a
basic understanding of the process, as it relates to a single pipe.
When water flows through a pipe, it must overcome the resistance
caused by its own turbulence and the friction of the interior pipe surface.
Valves, elbows and other fittings also add friction. The sum of these
frictions are called "head losses" or "pressure losses" or "head drops" or
simply "friction losses." The greater the water flow, the greater the
friction losses. If the flow of water in gallons per minute (gpm) is
doubled, the friction losses increases by about 4 times. At a given flow
rate, smaller pipes have greater friction losses than larger pipes.
11-3
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In addition to the friction losses which consume or use up pressure
head, additional work must be supplied to lift water to a higher level and
impart a velocity to the water, called velocity head. The pressures
created in a flowing water system are called the "dynamic pressures."
The pressures exerted when no water is flowing are called "static
pressures." Moving water is the job of pumps and/or gravity and is covered
in more detail in Chapter 6.
Experience has shown that the minimum water pressure at water use
fixtures should not be permitted to drop below 20 psi under peak flow
conditions in the system. System operating pressures in the range of 40 to
60 psi are adequate for most uses. Pressures should generally not exceed
100 psi to reduce the risk of damage to water heaters and other appurtenances.
Pressure reducing valves may be used in those parts of the system where high
pressures cannot be avoided.
Pipe Flow and Friction Loss-Tables and Graphs
The solution of problems dealing with pipe flow and the ensuing
friction losses has been reduced to simple tables and graphs for convenience.
A variety of tables and graphs are available in hydraulic text books and
handbooks. These tables and graphs are suited to small network analysis but
more complex problems are solved by computer techniques. Appendix C lists
some references for more detailed information.
The tables that follow are intended to show the process involved in
simple pipe sizing problems and are not intended for the serious reader who
may wish to actually design a system.
The tables assume new pipe and the friction losses do not take into
account the increased friction which will result from corrosion, tubercu-
lation, slime growths and encrustations. A design engineer takes this
11-4
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"aging" of pipe into consideration in the actual design of systems. Further-
more, the tables do not take into account the loss in pressure (usually quite sntaL
required to create the velocity of the water, called "velocity head."
Hydraulic handbooks will provide detailed information.
Table 11-1 shows a typical chart which lists:
- Quantity of water in gallons per minute (gpm)
- Various pipe sizes and pipe types, in this case 1 1/4", 1 1/2",
and 2" pipes, steel and plastic.
- The corresponding friction loss when water flows through the
pipe, in feet of water and also in lbs. per square inch (psi),
per 100 foot length of pipe.
If any 2 of the above variables are known, the 3rd may be determined
from the chart.
Table 11-2 lists several pipe fittings of various sizes and the allow-
ance which must be added in the form of equivalent length of pipe to account
for friction and head losses in each fitting. Charts are available for a
variety of fitting sizes and types. See Chapter 3 for estimation of peak deuceKk.
With the two charts, simple pipe hydraulic problems may be solved.
Example 1
Given: - Desired minimum water quantity = AO gpm
- Type of pipe; galvanized steel
- Length of pipe (distance between two points) = 500 feet
- Fittings; straight couplings - 21
90° ells - 2
45° ells - 2
Gate Valves - 1
- Desired maximum head or pressure loss = 25 feet or 10.8 psi.
Note: 2.31 feet of head = 1 psi
11-5
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Example 1 (continued)
To Find: Best pipe size.
Solution: The head losses in Table 11-1 are based upon 100 foot lenghts
of pipe.
1st trial: Move along chart from 40 gpm to head loss for 1 1/2"
(inside diameter) steel pipe. The head loss per 100' of pipe =
10.8 feet or A.7 psi. Since 500' of pipe are required, the
total head loss is 10.8 x 500/^qq = 54 feet
The head loss is obviously too great as only 25 feet is desirable.
2nd trial: Try a 2' pipe. The head loss is 3.1 feet per 100'
or 5 x 3.1 = 15.5 feet for the 500 foot pipe.
Now add the allowance for fittings in terms of extra length of
pipe. From Table 11-2, select the extra lengths as follows:
21 - 2" couplings at 2 feet each = 42 feet of equivalent pipe
2 - 2" 90° ells at 7 feet each = 14 feet
2-2" 45° ells at 4 feet each = 8 feet
1 - 2 " gate valve at 1.3 feet = 1.3 feet
Allowance for fittings = 65.3 feet
= assume 100 feet
From Table 11-1, the fittings will add an additional 3.1 feet
of head loss.
Total head loss = 15.5 feet for 500 foot of pipe
3.1 feet for fittings
18.6 feet
This is less than the desired maximum 25 feet of head loss and
is satisfactory. Therefore, a 2 inch pipe is the proper size.
11-6
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Example 2: Turn the problem around as follows:
Given: - Same pipe and fittings
- Diameter - 2"
- Maximum head loss = 25 feet
To Find: How much water will the pipe deliver at 25 feet head loss
Solution: Before using Table 11-1, the head losses attributable to the
fittings must be first subtracted to find the head loss
attributable to the pipe only. From Example 1:
25 feet - 3.1 feet = 21.9 feet (head loss of 500' of pipe)
Headloss per 100 foot of pipe = 21.9/5 = 4.4 feet
From Table 11-1, the system will deliver about 48 gpm.
11-7
-------
Table II -1: Friction Loss in Feet Per 100 Ft for Various Pipes at Various Water Flows
lk" ID IV'ID 2"ID
GPM
Stael
Plastic
Steel
Plastic
Steel
Plastic
Ft
Psi
Ft
Psi
Ft
Psi
Ft
Psi
Ft
Psi
Ft
Psi
10
1.8
.8
1.7
.7
12
2.5
1.1
2.3
1.0
1.2
.5
1.1
.5
14
3.3
1.4
3.1
1.3
1.5
.7
1.4
.6
16
4.2
1.8
4.0
1.7
2.0
.9
1.9
.8
18
5.2
2.3
4.9
2.1
2.4
1.1
2.3
1.0
20
6.3
2.7
o.O
2.6
2.9
1.3
2.8
1.2
25
9.6
4.2
9.1
3.9
4.5
2.0
4.3
1.9
1.3
. 6
1.3
.6
30
13.6
5.9
12.7
5.5
6.3
2.7
6.0
2.6
1.8 '
.8
1.8
.8
35
18.2
7.9
16.9
7.3
8.4
3.6
8.0
3.5
2.4
1.0
2.4
1.0
40
23.5
10.2
21.6
9.4
10.8
4.7
10.2
4.4
3.1
1.3
3.0
1.3
45
29.4
12.8
28.0
12.2
13.5
5.9
12.5
5.4
3.9
1.7
3.8
1.6
50
36.0
15.6
32.6
14.1
16.4
7.1
15.4
6.7
4.7
2.0
4.6
2.0
60
51.0
22.1
45.6
19.8
23.2
10.1
21.6
9.4
6.6
2.9
6.4
2.8
70
68.8
29.9
61.5
26.7
31.3
13.6
28.7
12.5
8.9
3.9
8.5
3.7
80
89.2
38.7
77.9
33.8
40.5
17.6
36.S
16.0
11.4
5.0
10.9
4.7
90
112.0
48.6
96.6
41.9
51.0
22.1
45.7
19.8
14.2
6.2
13.6
5.9
100
138.0
59.9
62.2
27.0
56.6
24.6
17.4
7.6
16.5
7.2
120
88.3
38.3
24.7
10.7
23.1
10.0
140
119.0
51.6
33.2
14.4
30.6
13.2
160
156.0
67.7
43.0
18.7
39.3
17.1
180
54.1
23.5
48.9
21.2
200
66.3
28.8
59.4
25.8
220
Areas
above the heavy lines are recommended
80.0
34.7
240
for normal operation
•
95.0
41.2
260
111.0
48.2
From: Water Systems Handbook, Water Systems Council
Table if-2: Allowance in Equivalent Length of Pipe for Friction Loss in Valves
Diameter
90° std.
45° std.
90° side
Coupling
Gate
Globee
Angle
of fitting
ell
ell
tee
or straight
valve
valve
valve
.
run
Inches
Feet
Feet
Feet
Feet
Feet
Feet
Feet
3/8
1
0.6
1.5
0.3
0.2
8
4
1/2
2
1.2
3
0.6
0.4
15
8
3/4
2.5
1.5
4
0.8
0.5
20
12
1
3
1.8
5
0.9
0.6
25
15
1 1/4
4
2.4
6
1.2
0.8
35
18
1 1/2
5
3
7
1.5
1.0
45
22
2
7
4
10
2
1.3
55
28
2 1/2
8
5
12
2.5
1.6
65
34
3
10
6
15
3
2
80
40
3 1/2
12
7
18
3.6
2.4
100
50
4
14
8
21
4
2.7
125
55
5
17
10
25
5
3.3
140
70
6
20
12
30
6
4
165
80
From: Manual of Individual Water Supplies, EPA
11-8
-------
PIPE MATERIALS
There is a wide choice of pipe materials available for the small
distribution system. These materials include cast iron, steel, asbestos
cement, wrought iron, copper, and plastic. Plastic pipe^^ is popular
for the small water supply system due to its resistance to corrosion, low
head loss, ease of installation and low cost. There are four principal
types of plastic available for water pipe: polyethylene, acryonitrile
butadiene styrene (ABS), polyvinyl chloride (PVC), and polybutylene.
Polyethylene. Polyethylene is an extruded semiflexible tubing manu-
factured in diameters up to 12 inches. The larger sizes are not economical
to produce as polyethylene's low tensile strength requires a thich wall.
It is supplied in coils of most any desirable length. The tubing should be
unpacked upon delivery and stored out of the ultraviolet rays of the sun-
light. Its flexibility permits it to be bent to make gradual curves.
Two types of fittings, insert and flared, are commonly used with
polyethylene pipe. Flaring is accomplished by heating and softening the
tubing until it can be flared with special tools. The simplest and surest
connection is made with insert fittings. The fitting is inserted in the
pipe endings and a stainless steel clamp is placed around the outside of
the tubing and tightened to compress the tubing around the fitting.
Acryonitrile Butadiene Styrene. ABS pipe is noted for its high
impact strength and is much more rigid than polyethylene. It first attracted
the interest of rural water districts, parks, and small towns where there
was a need for small diameter distribution pipes.
(1) Plastic piping used in water systems must meet the standards of the
National Sanitation Foundation (NSF). The American Water Works Associa-
tion (AWWA) established standards for larger diameter metal pipes.
11-9
-------
The pipe is manufactured in 20 foot lengths and is joined by solvent
welding the pipe ends to molded couplings. It can be mated with iron and
copper pipes using special adaptors.
Polyvinyl Chloride. Polyvinyl chloride (PVC) is mostly grey in
color, very rigid, and has one of the highest tensile strengths among the
thermoplastic pipes. It is used extensively for water distribution pipes,
replacing ABS in popularity.
PVC is manufactured in a variety of inside diameters and lengths but
usually 20 or 25 feet. Joints are made by using solvent welded fittings
as with ABS or rubber gasketed bell joints.
Polybutylene. Polybutylene pipe is used in municipal water systems
as a substitute for copper service lines. It should prove effective in
similar situations for small water systems.
Other Pipe Materials. Cast iron, steel pipe, asbestos-cement and
ductile iron, are used extensively in the larger water systems. Standards
for these piping materials are available from the American Water Works
Association, 6666 West Quincy Avenue, Denver, Colorado 80235.
Pipe Working Pressure
Pipe is rated according to its safe working pressure. Pipe with rated
working pressures of less than 150 psi should not be used in public water
systems. If operating pressure of the system exceeds 100 psi, pipes with
even greater working pressures than 150 psi should be considered.
Table 11-3 shows a comparison of plastic, copper and galvanized steel,
the piping materials most commonly used in the small non-municipal dis-
tribution systems.
11-10
-------
Table 11-3: Characteristics of Piping
Item
Plastic Pipe
Copper
Calvanized Steel
LffecL of Soil
Interior Corrosion
Water Pressure
l.ase of Installation
Cost
Codes
Limitations
Generally unaffected by
any type of soil.
Very resistant to inside
pipe corrosion.
Recommended water pres-
sures depend on type of
plastic. Use pipe with
pressure rating at
least 150 psi.
Easiest to install.
Affected by some soils.
Will be affected by water
containing free carbon
dioxide, high SO^.
Will withstand high water
pres sures.
Rigid tubing requires
sweated joints which are
easier than threaded.
Flexible tubing requires
flaring and fitting.
Deteriorates rapidly in
acid soils.
Will corrode if water is
acidic, alkaline, or hard.
Will withstand high water
pressures.
Requires the most time and
effort. Joints must be
fitted and threaded.
Usually the least expen-
sive in materials and
labor.
Usually the most expensive Moderate material cost, but
in materials, but has usually requires high labor
moderate labor cost. cost.
Codes vary from one area to another. Some codes may limit the use of,
or make it mandatory to use, one kind of pipe. Be sure to check local
codes before starting construction.
Can be damaged by sharp
objects. Will flatten
under excessive external
pressures. Most kinds can-
not be used for hot-water
pipes. Will absorb gas
and oil which cause taste
in the water. May be dam-
aged by rodents. Also,
resistance heating using
an electric welder cannot
be used to thaw out non-
riiital lir nine.
Some soils may cause
deterioration.
Should not be used for
underground piping as soils
often cause deterioration.
Cannot be used for all kinds
of water.
-------
VALVES
Air Release Valves
Air can enter a pipeline in a number of insidious ways: through
packing glands, leaky joints, and even from the water itself. Unless
passage is fast enough to purge any buildup of air at high points along
the pipeline, air pockets may form which will impede the flow of water.
Properly located air-release valves will minimize the problem.
All air-release valves should be inspected periodically. It is best
to install them in a valve vault, and below the frost line in freezing
areas. Valve vaults should be properly ventilated and drained. An
improperly vented vault may become pressurized during the discharge of
air, and during periods of inflow the vault may be subjected to negative
pressures. Inadequate draining may result in a flooded vault and back
siphonage into the system resulting in a health hazard, Vault drains
shall not be connected directly to any storm or sanitary sewer, whether
installed in a pit, chamber, or by other means. Drainage should be made
to the ground if possible, or to approved underground absorption pits.
Outside vents should be screened to discourage the entrance of insects and
animals. In all installations, it is suggested that an isolating valve be
installed at the air valve to permit inspection and servicing.
Surge Control Valves
Surge pressures occur in systems whenever the water velocity is
suddenly changed (decreased or increased). Typical causes of sudden
changes of velocity are quick opening or quick closing of a line valve,
sudden starting or sudden stopping of a pump.
If flow in a pipe is changed suddenly, the built-up energy of the
flowing water produces a high pressure that may result in damage.
11-12
-------
Surge pressures can reach destructively high levels unless some type
of surge control is provided. The simplest form of a surge-contral valve
is the pressure-relief valve. This valve responds to pressure variations
at its inlet and is designed to open very rapidly at an increase in pressure
above the set point of the control. The pressure-relief valve is most
commonly installed on the side outlet of a tee at a specific point in a
system, and its discharge is to atmosphere.
Valves
Valves shall be uniformly located and mapped for ready use. A valve
box, with its cover at grade, should be placed in the distribution system
so that a short section of main may be repaired or serviced without inter-
ruption of service to more than one block. Valves should be located on all
branches from feeder mains and between distributors and fire hydranLs.
Three valves should be used at crosses and two valves at tees. On arterial
mains and minor distributors, valves should be placed at least every 1,200 ff«t.
Gate valve construction and materials should comply with the current
American Water Works Association Standard C500 - Gate Valves.
Dead Ends
Dead end lines should be avoided by looping where possible. Unloosed
mains should be equipped with a fire hydrant, flushing hydrant, or a blow-off.
The flushing hydrant or blow-off valve shall be at least the size of the main
or four inches, whichever is smaller. No flushing device shall be directly
connected to a sanitary sewer or storm drain.
11-13
-------
THRUST BACKING AND ANCHORAGE OF FITTINGS
Thrust backing is needed wherever a pipeline:
1. Changes direction as at tees, bends and crosses;
2. Changes size, as at reducers;
3. Stops, as at a dead end; and
4. Valves, at which thrust develops when closed.
Size and type of backing depends on pressure, pipe size, kind of
soil and type of fitting. The following steps are used to determine the
bearing area required for a thrust block
Example: A 90° bend for a 2" - 100 psi line. Soil is sand.
(1) Refer to the following and note that the thrust developed for
each 100 psi water pressure at a 2" - 90° bend is 645 lbs.
Table 11-4: Source: Johns Manville Pipes, Denver, Colorado 80217
Thrust
at Fittings in Lbs. at
100 Lbs. per
Square Inch, Water Pressure
Pipe
90°
45°
Tee and
Size
Bend
Elbow
Deadends
lh"
415
225
295
2 "
645
350
455
2V'
935
510
660
3 "
1395
755
985
4 "
2295
1245
1620
6 "
4950
2680
3500'
8 "
8375
4540
5930
(2) In Table 11-5, find the bearing power of sand as 2000 lbs.
per square foot. Dividing the total force of 645 lbs. by
2000 lbs., a total area of thrust backing required of 0.32
square feet.
11-14
-------
Table 11-5:
Safe Bearing Load of Soils
Soil Lbs./sq. ft.
Muck, peat and similar 0
Soft clay 1,000
Sand 2,000
Sand and Gravel 3,000
Sand and gravel cemented with clay 4,000
Hard shale 10,000
Note: Allowance in total bearing area should be made for possible water
hammer in the line.
Upward Thrusts at Fittings
Where a fitting is used to make a vertical bend, anchor the fitting
to a thrust block braced against undisturbed soil. The thrust block should
have enough resistance to withstand upward and outward thrusts at the fitting.
Anchorage of Pipe on Slopes
Anchors on slopes are needed only when there is the possibility of
backfill slipping downhill and carrying the pipe with it. Usually well
drained soil, carefully tamped in layers, will not slide and pipe anchors
will not be required. Where soil slippage is a possibility, anchors keyed
into undisturbed soil may be fastened to every other length of pipe.
Anchorage of Valves in the Line
Under pressure conditions, valves in sizes three inches or larger,
including those in hydrant run-outs, must be anchored against the
thrust created when the valve is closed. Area of undisturbed soil which
braces the thrust block must be large enough to withstand the thrust in
whatever direction it is exerted.
11-15
-------
SERVICE LINES AMD CONNECTIONS
A service line is the piping which delivers water from the mains to
the consumer or water use site. A service line of 3/4 inch to 1 inch may
be ample to serve a single family service. A larger service line may be
(2)
needed to furnish other needs . The service connection must be sized to
meet the peak demands. There is a wide choice of materials for service
line piping. The minimum size and material is often prescribed by estab-
lished local policy for the different types of services. Consult local
plumbing codes.
Galvanized steel pipe is widely used for service lines. It is strong
and reasonably priced. However, some waters and soils cause the galvanized
pipe to deteriorate rapidly due to corrosion.
Copper tubing is widely used and offers several advantages: Copper
tubing is easy to handle because of its flexibility. It does not corrode
readily, joints are easily made and its smoothness permits a high carrying
capacity.
Cast iron pipe is satisfactory for service lines. It is generally
used for larger sizes of from 1 1/4 inches upwards. Sizes above two
inches are the most satisfactory.
Plastic pipe is used for service lines. Manufacturers claim the
following advantages: (1) Ends of pipe may be heated, flared and used
with copper connections; (2) It is light in weight, therefore it can be
handled easily; (3) Withstands corrosion, so it has a long life carrying
capacity; (4) Withstands low temperatures; and (5) Costs less than metal
pipe. On the other hand, the pipe cannot be electrically thawed or heated
which mav be a disadvantage in colder climates. Plastic pipe is available
with adaptors to provide for simple connections to asbestos-cement, cast
iron, steel and other pipe materials.
I
(2) For details, consult "Sizing Warer Service Lines and Meters". Manual 22,
American Water Works Association, 6666 Quinsy Avenue, Denver, CO. 80235.
11-16
-------
SEPARATION OF WATER MAINS AMD SEWERS
Whenever possible, water mains shall be laid at least 10 feet,
horizontally, from any existing or proposed sewer. Should local conditions
prevent a lateral separation of 10 feet, a water main may be laid closer
than 10 feet to a sewer if the sewer is constructed with pressure pipe
specifications including joints and tested at 15 psi and:
a. It is laid in a separate trench.
b. It is laid in the same trench with the sewer, provided that the
water main is located on an undisturbed earth shelf above the
sewer and located on one side of the sewer.
c. In either case the elevation of the bottom invert of the water
main is at least 18 inches above the top (crown) of the sewer.
Whenever sewers cross under water mains, the water main shall be laid
so that the bottom of the water main is at least 18 inches above the top of
the sewer. This vertical separation shall be maintained for that portion of
the water main located within 10 feet horizontally of any sewer it crosses.
No water main shall pass through, or come into contact with any part
of a sewer manhole.
There shall be no physical connection between the distribution system
and any pipes, pumps, hydrants, or tanks which are supplied or may be supplied
with a water that is, or may be contaminated except as approved in writing by
the State regulating agency. See cross-connections in Chapter 15.
Water mains within 10 feet of railroad tracks or crossing under rail-
road tracks shall be equipped with clamps or other acceptable provisions to
minimize the affect of vibration. Mains crossing under waterways shall be
valved at both ends of the crossing to permit isolation for repair, and
testing of the section. Sampling taps shall be provided to facilitate sani-
tary control. These Laps shall nut be subject to flooding.
11-17
-------
DISINFECTION
Even under the best conditions, the construction of new water lines
subjects the interior of the pipes and fitcings to possible serious
contamination. The repair of faulty or ruptured water lines and fittings
usually occurs under adverse conditions and the threat of contamination
is ever present. Before these sections of water lines are placed into
service, they must be flushed, if possible, and always disinfected with
chlorine solutions. During construction, precautions should be taken to
avoid unnecessary contamination. When working under adverse conditions,
particularly in the repair of faulty or ruptured lines or fitting, it is
prudent to spread generous amounts of 70% calcium hypochlorite, either
in granular or tablet form in the working trench. The chlorine will go
into solution slowly and will significantly reduce gross contamination.
Disinfection is commonly accomplished by one of four methods. All
are described in an American Water Works Association manual on Water Main
Disinfection, AWWA C601-68, 2 Park Avenue, New York, NY 10016.
Continuous Feed Method
This method has an advantage for disinfection of long sections of
pipe. The disinfection is accomplished after construction by injecting
chlorine solutions (either a gas chlorinator or hypochlorinator may be
used) into the pipe through a corporation cock or other fitting. The
line is first flushed to remove accumulated material. The chlorine
dose is ususally 50 mg/1 with a 24 hour contact period. The chlorine
solution is injected as the line is being filled. This method requires
careful control and specialized equipment and should not be attempted by
inexperienced contractors or repair crews.
11-18
-------
Slug Method
This method is similar to the previous method but employs high
doses as high as 500 mg/liter with a 1/2 hour retention. It is par-
ticularly applicable for large diameter water mains and where the pipe
must be put into service without long delays.
Tablet Method
Calcium hypochlorite (70% available chlorine) is prepared by
several firms in tablet form under various labels. A swimming pool
supply store is a good source. These tablets provide a simple and popular
method for water line disinfection. The tablets are attached on the
inside of the pipe (top side) as the line is being laid with an adhesive.
Permatex No. 1 adhesive manufactured by the Permatex Company is recommended
by the American Water Works Association. The tabulation that follows
lists the doses suggested by AWWA. This method is considered superior to
the use of granular calcium hypochlorite which will flush away quickly
before dissolving. The water line should be filled slowly to reduce the
chance of flushing away the tablets. The method has some disadvantages:
(1) The line cannot be flushed before disinfection, (2) the tablets will
o c
not readily dissolve at water temperatures below 41 F (5 C), and (3) the
tablets are difficult to insert in small diameter pipes.
11-19
-------
Table 11-6: Chlorine Tablets Required to Produce 50 mg/1 Concentration of
Chlorine in Pipe Sections of Various Lengths and Diameters
(AWWA C 601-68).Retention Period of 24 Hours.
Length of Pipe Diameter in Inches
Section in Feet
2
4
6
8
13 or less
1
1
2
2
13
1
1
2
3
20
1
1
2
3
30
1
2
3
5
AO
1
2
4
6
Notes: - Based upon tablets of 3 3/4 grams of available chlorine.
- Retention period is 24 hours with above doses.
- Double the number of tablets for 100 mg/1 dose and 3 2 hours retention.
- Use 4 times the number of tablets for 200 mg/1 and 2 hours retention.
- For pipes less than 2 inches diameter, use the 2 inch diameter pipe
dose.
The water line should be filled slowly and tested at the extreme end
until a strong chlorine solution is present. Allow the chlorinated water to
stand in contact with the pipe for the full retention period. Then flush
until the chlorine residual by the DPD test (Chapter 9) shows a residual of
1.0 mg/1 or less. A sample of water from the disinfected line should be
collected for coliform test by an approved laboratory. If the test indicates
ineffective disinfection, it must be repeated.
Emergency Repairs and Disinfection
Where a short section of pipe or a fitting must be repaired and placed
into immediate service, the section may be thoroughly swabbed with full
strength 5.25% sodium hypochlorite (common household bleach) during the
repair before installation. Care should be taken to insure complete coverage
of all inner surfaces.
11-20
-------
Caution on the Storage and Use of Calcium Hypochlorite
Calcium hypochlorite is a highly reactive chemical when wet and should
be stored in dry places and away from organic substances as violent reac-
tions, including explosion and fire, may result. Potential contaminates
include soap products, cleansing oils, mineral oils, petroleum products,
food and beverages, paper and similar materials. Since the product is
readily purchasable, avoid storing large quantities.
State Agency Approval
The State agency will be the final authority on disinfection standards
and should be consulted for special requirements.
11-21
-------
PART II
OPERATION AND MAINTENANCE
CHAPTERS 12 through 15
-------
CHAPTER 12
NATIONAL DRINKING
WATER REGULATIONS
Applicability - Primary Regulationsi Maximum
Contaminate Levels, Monitoring, Reporting,
Public Notification and Record Keeping -
Secondary Regulations - Sampling Techniques
INTRODUCTION
As part of the National Safe Drinking Water Act (SDWA), the
Environmental Protection Agency has promulgated National Primary
Drinking Water Regulations, applicable to public water systems
throughout the nation. In addition, Secondary Regulations have
been prepared as guidelines. Designated counterpart State
agencies^^ which accept and qualify for enforcement responsibi-
lities will supervise and enforce the regulations and may also
enforce certain additional regulations of their own. While the
Primary Drinking Water Regulations are devoted to matters affect-
ing the health of consumers, the Secondary Regulations deal with
the aesthetic qualities of drinking water. Both are summarized in
this Chapter.
The Primary Regulations include«
- Siting requirements for new or expanded systems
- Maximum Contaminate Levels for inorganic and organic
chemicals, turbidity and microbiological (coliform) levels
- Monitoring and testing requirements
- Reporting, public notification and record keeping
- Record maintenance
The Primary Regulations apply to all public water systems but a
distinction is made between "community" and "non-community"
(l) See Listing of otate Agencies and EPA Regional Offices in
the Appendix B.
12-1
-------
systems. Since a community system supplies water to people at
the place where they normally live and stay for extended periods,
the consumers are subjected to whatever contaminates may be pre-
sent on a more or less continuous basis. Therefore, the full
range or maximum contaminate levels apply to community systems.
On the other hand, the non-community system serves mostly transients,
travelers and people with shorter term exposures and thus the re-
quirements are less stringent. A partial list of community and
non-community water systems is shown on Page 2, Purpose and Use of
the Manual.
The owners or operators of public water systems are responsible,
under the Safe Drinking Water Act, for establishing the procedures
necessary to meet the requirements of the Primary Drinking 'water
Standards. The water supplier should become thoroughly familiar
with the requirements. The State agency may be contacted for fur-
ther information.
The summary which follows is an outline of requirements under
the National (Interim)^*^ Primary Drinking Water Regulations as
they re]ate to the responsibilities of those who supply water to
the public.
SUMMARY OF PRIMARY DRINKING WATER REGULATIONS
SITING REQUIREMENTS (Sec. 141.5)
Before entering into a financial committment, or initiating
construction of a new public water system or increasing the capacity
of an existing public water system the owner must notify the State
agency.
(2) The regulations are considered interim at this time as they
will undergo refinement in the future as nev; pertinate infor-
mation becomes available.
12-2
-------
Where the term "owner," "supplier," "water purveyor" or
"operator" is used, it means the person, corporation, company,
association, partnership. State, municipality or Federal agency
which supplies water to the public.
Where the term "State agency" is used, it means the agency
of State government which has jurisdiction over water supplies
(See Appendix £).
APPLIES TO ALL PUBLIC WATER SYSTEMS
(3)
A "public water system" is defined *" as a system for the
provision to the public of piped water for human consumption,
if such system has at least fifteen service connections or regu-
larly serves an average of at least twentv-five individuals daily
at least 60 davs out of the year. A "community water system" is
defined as a public water system which serves at least fifteen
connections used by year-around residents or regularly serves at
least twentv-five vear-around residents. A "non-community water
system" is a public water system that is not a community water
1
system. Privately owned as well as publicly owned systems are
included.
13) National Interim Primary Drinking Water Regulation, U.S.
Environmental Protection Agency, Federal Register, Volume
*f0, No. 2^8, December 2k, 1975.
12-3
-------
SUMMARY OF MONITORING REQUIREMENTS
MICROBIOLOGICAL
Contaminant
Surface Source
Ground Source
Coliform Bacteria
Monthly, based on popu-
lation served.
Community systems of
less than 1000 pe°p]-e>
a mi n't mum of one per
ronth.
Non-community systems,
a minimum of one per
calendar quarter.
Same as for surface
sources, except that
State agency may re-
duce to one sample
per calendar quarter.
INORGANIC CHEMICALS (Applies only to community systems except for Nitrate
which applies to both community and non-community)
Contaminant
Surface Source
Ground Source
Arsenic
Barium
Cadmium
Chromium
Lead
Mercury
Selenium
Silver
Fluoride
Nitrate
Analysis completed June
24, 1978. Thereafter
at one year intervals.
Analysis completed
within two years after
effective date, There
after at three year
intervals.
ORGANIC CHEMICALS
(Applies only to community type systems)
Contaminant
Surface Source
Ground Source
Endrin
Lindane
Methoxychlor
Toxaphene
2,4-D
2,4,5-TP Silvex
Analysis completed June
24, 1978. Thereafter
at three year intervals
Analysis only if re-
quired by the State.
RADIOACTIVITY
Contaminant
Surface Source
Ground Source
Natural Radioactivity Analysis completed June Analysis completed
24, 1980. Thereafter within three years
at four year intervals. after effective date.
Thereafter at four
year intervals.
Note: There is also a requirement for man-made radioactivity, but this
applies only to surface source systems serving a population of
over 100,000.
12-4
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MONITORING AND ANALYTICAL REQUIREMENTS
C3>
MICROBIOLOGICAL (Sec. 141.14 and 141.21)
Water samples for coliform bacteria shall be collected»
1. At points representative of distribution system
conditions.
2. At regular time intervals and based on the popula-
tion served.
Sampling Freouencv
Surface waters - monthly, based on population served,
with minimum of one per month for systems serving between
2$ and 1000 people, except for non-community water systems
which shall be sampled a minimum of once each calendar
quarter during which it serves the public
Ground waters - same as surface water supplies. Systems
serving 25 - 1000 may, with written permission of the L>tate
agency, reduce sampling frequency based on a history of no
coliform bacterial contamination and on a sanitary survey
showing the water system is supplied solely by a protected
ground water source and is free of sanitary defects.
The State agency may require more frequent sampling.
12-5
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Maximum Contaminant Level
Fermentation tube method - ooliform bacteria shall not
be present in any of the following 10 ml standards portions:
1. more than 10 percent of the portions in any re-
porting period;
2. three or more portions in more than one sample when
less than 20 samples are examined in any reporting
period; or
3. three or more portions in more than five percent of
the samples when 20 or more samples are examined.
Membrane filter method - in a 100 ml sample, colifonn
bacteria shall not exceed:
1. one oolony as the arithmetic mean of all samples
examined in any reporting period;
2. four colonies in more than one sample when less
than 20 are examined in that reporting period;
3. four oolonies in more than five percent of the
samples when 20 or more are examined.
Determination of maximum contaminant levels for ooli-
form bacteria may, at the discretion of the State, be based
upon a three month reporting period, provided the system is
required to take less than four samples per month. This
flexibility allows the small system (serving not more than
3300 people) to average bacteriological samples over a more
representative time frame.
12-6
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Action By Purveyor
When colifbrm In a single sample exceeds four per 100
ml by the membrane filter method - the purveyor must oollect
et least two consecutive daily check samples from the same
point and additional needed samples until two consecutive
samples show less than one colifonn per 100 ml.
or,
When colifonn occurs in three or more 10 ml portions of
a single sample by the fermentation tube method - oollect et
least two consecutive daily check samples until results from
two consecutive daily samples show no positive tubes.
Check samples shall not be included in calculating the
total number of samples taken each month to determine com-
pliance with the number required based on population.
When coliform presence is confirmed by any check sample
the purveyor must report to the btate agency within ^8 hours.
When maximum contaminant levels are exceeded, the pur-
veyor must report to the btate agency and notify the public.
Chlorine Residual
Based upon a sanitary survey which has determined that a
community water system is free of sanitary defects and water
sources are adequately treated and/or protected, the purveyor
may request State approval for substitution of chlorine resi-
dual monitoring for not more than 75 percent of the micro-
biological samples required, provided chlorine residual
samples are taken at a frequency of at least four for each
substituted microbiological sample - and at least daily
12-7
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residual determinations are made - and that the system main-
tains no less than 0.2 mg/1 free chlorine residual throughout
the distribution system. If less than 0.2 mg/1, retest
within one hour. If original analysis is confirmed, report
to the State within 48 hours, collect sample for coliform
analysis and report the results to the State.
TURBIDITY SAMPLING - Applies Only to Surface Waters
(Sec. 141.13 and 141.22}
Sampling Frequency
Rjrveyor takes samples of water at representative entry
points to the distribution system at least once per day.
Maximum Contaminant Level (Measured by the Nephelometer Method)
1. One turbidity unit (TU) as a monthly average -
except five or fewer TU's monthly average may be
allowed by the State if the purveyor demonstrates
that it does not: (Averages are rounded to nearest whole
number)
a. Interfere with disinfection.
b. Prevent effective distribution disinfection.
c. Interfere with microbiological determination.
2. Five turbidity units based on an average for two
oonsecutive days. (Averages are rounded to nearest whole
number)
Action by Purveyor
If turbidity exceeds maximum oontaminant level - resample
within one hour - if repeat sample exceeds limit, report to
the State within 48 hours.
If monthly average exceeds limit or if the average of two
samples taken on consecutive days exceeds five TU the supplier
shall - report to the State and notify the public.
12-8
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INORGANIC SAMPLING (Sec. 141.11 and 141.23) - Applies only
to community systems, except for Nitrate which applies to
"both community and non-communitv systems.
Sampling Frequency
analysis
Surface waters - complete/by June 1978 and repeat yearly.
analysis
Ground waters - complete/by June 1979 and repeat at three
year intervals.
Maximum Contaminant Level Other Than Fluoride
Contaminant Level (mg/l) Contaminant Level (mg/l)
Arsenic 0.05 Mercury 0.002
Barium 1. Nitrate as N 10.
Cadmium 0.010 Selenium 0.01
Chromium 0.0$ Silver 0.05
Lead 0.05 Fluoride See below
Maximum Contaminant Levels for Fluoride
When the annual average of the maximum daily air temperature for
the location in which the community water system is situated is
the following, the corresponding maximum level for fluoride ares
Temperature (°F) Level (mg/l)
53•7 and below 2.4
53.8 - 58.3 2.2
58.4 - 63.8 2.0
63.9 - 70.6 1.8
70.7-79.2 1.6
79.3 - 90.5 1.^
12-9
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Action By Purveyor
If result of an analysis exceeds maxlinum contaminant
level - supplier shall report to the State within 7 days end
initiate three additional analyses within one month. When
the average of fbur analyses within one month exceeds maximum
level, report to the State within 48 hours and notify the
public.
Fbr nitrate only, when an analysis exceeds maximum
level, supplier shall take 0 seoond sample within 24 hours.
When the average of two samples exceeds the maximum level,
report within 48 hours and notify the public.
12-10
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Monitoring after public notification shall "be at a
frequency determined by the State agency and shall con-
tinue until two consecutive samples do not exceed maximum
contaminate level or until a schedule for enforcement action
becomes effective.
ORGANIC SAMPLING (Sec. 1^1.12 and lhl.2k - Applies only to
community systems.
Sampling Frequency
Surface sources - complete by June 1978 - repeat at
State agency specified intervals but no less than three
year intervals.
Ground water sources - analyses completed as specified
by the enforcing agency.
Maximum Contaminant Level
Contaminant Level (ug/l) Contaminant Level (ug/l)
Endrin 0.2 Toxaphene 5.0
Lindane.. 4.0 2,4-E. 100.
Methoxychlor 100. 2,4,5-TP Silvex.... 10.
Action By Purveyor
If analyses exceed limit, notify the enforcing agency
within seven days and initiate three additional analyses
within one month.
When average of four analyses exceeds maximum level,
report to the State agency within 48 hours and notify the
public. Monitoring after public notification shall be at a
frequency designated by the State agency and shall continue
until two successive samples do not exceed limit, or until
the State agency establishes a schedule for enforcement.
12-11
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APPROVED LABORATORIES (Sec. 141.28)
For compliance determination, water samples will be
considered only if analyzed by a laboratory approved by
the State agency - except that turbidity and chlorine
residual may be performed by any person acceptable to the
State agency.
MONITORING OF CONSECUTIVE COMMUNITY WATER SYSTEMS (Sec. 141.29)
When a purveyor supplies water to one or more other
public water systems - the State agency may modify the
monitoring requirements if the systems may be considered a
single system. The modified system will be monitored as
specified by the State agency and as concurred with by the
E.P.A.
Each of the separate water systems is responsible for
the modified sampling program applying to its system.
REPORTING. PUBLIC NOTIFICATION, RECORD K-EhriNG
REPORTING REQUIREMENTS (Sec. 141.31)
1. Report to the State within 40 days results of all tests.
2. Report to the State within 48 hours of failure to comply
with any primary water regulation including monitoring.
PUBLIC NOTIFICATION (Sec. 141.32)
When a community water'system fails to comply withi
1. An applicable maximum contaminant level.
2. An applicable testing procedure.
3. Scheduled corrections.
4. Required monitoring.
12-12
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A. Notify persons served by the system in first set of
water bills or by written notice within three months,
and repeat once every three months as long as unsatis-
factory conditions exist.
B. If the water system fails to meet an applicable maximum
contaminant level, the supplier in addition to A (above)
shall notify the public»
1. Within 7 days of learning of the failure - by copy
of notice to radio and television stations serving
the area.
2. Within 14 days of learning of the failure - by publi-
cation (three consecutive days) in a newspaper with
general circulation in the area served by the system.
If area is not served by a daily newspaper - publish
on three consecutive weeks in a weekly newspaper.
If no daily or weekly newspaper is available, post
in post offices in the area served by the system.
C. Notices will be written in a manner reasonably designed
to inform fully the users of the system.
Notice shall disclose all material facts regarding
the subject including the nature of the problem and,
where appropriate, a clear statement that a primary
drinking water regulation has been violated and any
measures that should be taken by the public.
Notices may include a balanced explanation of the
significance or seriousness to public health and a fair
explanation of steps taken to correct the problem.
12-13
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D. Notice to the public may be given by the State on behalf
of the purveyor.
E. When notification by mail is required by A (above) but
notification by newspaper, radio or television is not
required by B (above) the State may order the supplier
to provide notification by newspaper, radio and tele-
vision when circumstances make more immediate or broader
notice appropriate to protect public health.
F. Notifications to the oonsumer and the general public by
the water purveyor for non-compliance with regulations
covering maximum contaminant levels is the sole responsi-
bility of the water purveyor. Notification by the water
purveyor is necessary regardless of who carries out for
the purveyor the chemical, bacterial or other analyses:
a. the water purveyor itself,
b. a oounty or other local agency laboratory,
c. the State laboratory, or
d. a commercial laboratory.
In all cases for the analytical results to be
acceptable they must have been from a laboratory approved by
the State.
12-14
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RECORD MAINTENANCE (Sec. 1U1.33)
Each water purveyor must maintain the following reoords
of:
1. Bacteriological analyses - for at least five years.
Chemical analyses - for at least 10 years. Actual
laboratory reports may be kept, or data may be
transferred to tabular summaries, provided that
the following information is included:
a. Date, place, time of sampling, name of person
collecting.
b. Identification of routine distribution system
sample, check samples, raw or process water
samples, special purpose samples.
c. Date of analyses.
d. Lab and person responsible for performing
analysis.
e. Analytical method used.
f. Results of analysis.
2. Reoords of action taken to oorrect violations - for
at least three years after lest action was taken
with respect to particular violetion.
3. Copies of written reports, summaries or communice-
tions relating to sanitary surveys conducted by
itself, private consultant or local, state or
federal agency - for at least 10 years after com-
pletion of sanitary survey involved.
4. Records concerning scheduling of improvements - not
less than five years following expiration of sched-
uling time.
12-15
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NATIONAL SECONDARY DRINKING WATER GUIDELINES
While the Primary Regulations are devoted to constituents and regula-
tions affecting the health of consumers, Secondary Regulations are those
which deal with the aesthetic qualities of drinking water. The Secondary
Guideline "levels may not have a significant direct-impact on the
health of consumers, but their presence in excessive quantities may discourage
the utilization of a drinking water supply by the public.
The Secondary Guidelines are not Federally enforceable but are intended
as guidelines for the States. The State agency should be consulted.
SECONDARY MAXIMUM CONTAMINANT LEVELS
The Secondary Drinking Water Guidelines contain maximum contaminant
levels for chloride, color, copper, corosivity, foaming agents, hydrogen
sulfide, iron, manganese, odor, pH, sulfate, total dissolved solids and zinc.
Chloride in reasonable concentrations is not harmful to humans, but m
concentrations above 250 mg/1 chloride causes a salty taste in water which
is objectionable to many people. Chloride can be removed from drinking
water by distillation, reverse osmosis or electrodialysis. In some cases
the entry of chloride into a drinking water source can be minimized by
proper aquifer selection and well construction.
12-16
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Color may be indicative of dissolved organic material which may lead
to generation of trihalomethanes and other organohalogen compounds during
chlorination. Color can also be caused by inorganic substances such as
manganese or iron. Color becomes objectionable to most people at levels
over 15 C.U. (Color Units). In some cases, color can be objectionable at
the 5 C.U. level. Depending on the nature of the substances causing color,
conventional water treatment (flocculation and filtering), oxidation or
(4)
carbon adsorption are processes used for removing color.
Copper is an essential and beneficial element in human metabolism, bur
copper imparts an undesirable taste to drinking water. Small amounts of
copper are generally regarded as nontoxic. Copper can be removed from
(4)
water by ion exchange, and by proper control of pH, where the source of
copper is the corrosion of copper pipes.
Corrosivity is a complex characteristic of water related to pH,
alkalinity, dissolved oxygen and total dissolved solids plus other
factors. A corrosive water, in addition to dissolving metals with which
it comes in contact, also produces objectionable stains on pumbing fixtures.
Corrosivity is controlled by pH adjustment, the use of chemical stabilizers,
or other means which are dependent upon the specific conditions of the
(4)
water system .
Foaming is a characteristic of water caused principally by the pre-
sence of detergents and similar substances. Water which foams is definitely
objectionable and considered unfit for consumption. The foamability of water
is measured by the quantity of methylene blue active substances (MBAS)
present. Foaming substances can be removed from drinking water by carbon
adsorption, but it is preferable to prevent contamination of water by
(4)
foaming substances .
(4) See Chapter 10, Treatment and Conditioning
12-17
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Hydrogen sulfide is an odorous gas. Its presence in drinking water is
often attributed to microbial action on organic matter or the reduction of
sulfate ions to sulfide. In addition to its obnoxious odor, hydrogen
sulfide in association with soluble iron produces black stains on laundered
items and black deposits on piping and fixtures. Hydrogen sulfide is
(4)
removed from drinking water by aeration or chemical oxidation.
Iron is a highly objectionable constituent of water supplies for
either domestic or industrial use. Iron may impart brownish discolorations
to laundered goods. The taste that it imparts to water may be described
as bitter or astringent, and iron may adversely affect the taste of other
beverages made from water. The amount of iron causing objectionable taste
or laundry staining constitutes only a small fraction of the amount
normally consumed in the daily diet and thus does not have toxicologic
significance. Iron can be removed from water by water filtration treat-
ment processes or ion exchange and also by oxidation processes followed
by filtering. If the iron comes from the corrosion of iron or steel piping,
(4)
the problem can often be eliminated by practicing corrosion control-
Manganese, like iron, produces discoloration in laundered goods and
impairs the taste in drinking water and beverages, including tea and
coffee. At concentrations in excess of 0.05 milligrams per liter,
manganese can occasionally cause buildup of coatings in distribution
piping which can slough off and cause brown spots in laundry items and
unesthetic black precipitates. Manganese can usually be removed from
water by the same process used for iron removal.
Odor is an important aesthetic quality of water for domestic consumers
and process industries such as food, beverage and pharmaceutical manufacturers,
which require water essentially free of taste and odor. It is usually
12-18
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Impractical and often impossible to isolate and identify the odor-producing
chemical. Evaluation of odors and tastes is thus dependent on the individual
senses of smell and taste. In many cases, sensations ascribed to the sense
of taste are actually odors. Odors are usually removed by carbon adsorption
(4)
or aeration.
The range of £H in public water systems may have a variety of esthetic
and health effects. Corrosion effects are commonly associated with pH
levels below 6.5. As pH levels are increased to about 8.5 mineral incrusta-
tions and bitter taste can occur, the germicidal activity of chlorine is
substantially reduced and the rate of formation of trihalomethanes is
significantly increased. However, the impact of pH in any one water system
will vary depending on the overall chemistry and composition of the water
so that a more or less restrictive range may be appropriate under specific
circumstances.
Sulfate may cause detectable tastes at concentrations of 300-400 milli-
grams per liter; at concentrations above 600 milligrams per liter it may
have a laxative effect. High concentrations of sulfate also contribute to
the formation of scale in boilers and heat exchangers. Sulfate can be
removed from drinking water by distillation, reverse osmosis or electrodialysis.
The laxative effect noted above seldom affects regular users of the water
but transients are particularly susceptible. For this reason it is likely
that most States will institute monitoring programs for sulfate, and that
transients should be notified if the sulfate content of the water is high. Such
notification should include an assessment of the possible physiological
effects of consumption of the water.
Total Dissolved Solids (TPS) may have an influence on the acceptability
of water in general, and in addition a high TDS value may be an indication
of the presence of an excessive concentration of some specific substance
12-1*?
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that would be aesthetically objectionable to the consumer. Excessive hardness,
taste, mineral deposition or corrosion are common properties of highly
mineralized water. Dissolved solids can be removed by chemical precipitation
in some cases, but distillation, reverse osmosis, electrodialysis and ion
exchange are more generally applicable.
Zinc, like copper, is an essential and beneficial element in human
metabolism. Zinc can also impart an undesirable taste to water. At higher
concentrations, zinc salts Impart a milky appearance to water. Zinc can be
removed from water by water filtration treatment processes or ion-exchange.
But,since the source of zinc is often the coating of galvanized iron,
corrosion control will minimize the introduction of zinc into drinking water.
At the same time, corrosion control will minimze the introduction of lead
and cadmium into the drinking water, since lead and cadmium are often con-
tamiants of the zinc used in galvanizing.^
Contaminates Considered But Not Included In The Regulations
In addition to the above contaminants, hardness, alkalinity, phenols, and
sodium, were considered.
Since high levels of hardness have significant aesthetic and economic
effects, the removal of hardness (softening) can be considered beneficial
from a non-health standpoint. However, correlations between the softness
of water and the incidence of cardiovascular disease have been shown, in
some studies, so the practice of softening drinking water is being dis-
couraged by some scientists and physicians. Available information is not
sufficient at this time to balance the aesthetic desirability of setting a
(4)
limit for hardness against the potential health risk of water softening.
Phenols, particularly the chlorophenols, are esthetically objection-
able because of the taste and odor they produce. Some of the chlorophenols
produce a detectable taste or odor at concentrations as low as 1 ppb. While
11-20
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analysis for phenols in this concentration area might present some diffi-
culties, the odor test can easily detect the presence of these compounds
and thus makes the inclusion of a limit for phenols unnecessary.
The principal concern with respect to sodium relates to its potential
health significance rather than to aesthetic effects. However, existing
data did not support the establishment of a Maximum Contaminant Level for
sodium in the Interim Primary Drinking Water Regulations. It has been
recommended that the States institute programs for regular monitoring of
the sodium content of drinking water served to the public, and for
informing physicians and consumers of the sodium concentration in drinking
water. By this means, those affected by high sodium concentration can make
adjustments to their diets, or seek alternative sources of water to be used
for drinking and food preparation.
Monitoring
Since these regulations are not federally enforceable, there are no
associated uniform monitoring requirements. However, individual State
agencies may establish requirements.
12-21
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SUMMARY
Secondary Guideline Levels
The Secondary Maximum Contaminant Levels for public water systems are as follows;
Contaminant: Level
Chloride 250 mg/1.
Color 15 Color Units.
Copper 1 mg/1.
Corrosivity Non-corrosive.
Foaming Agents 0.5 mg/1.
Hydrogen Sulfide 0.05 mg/1.
Iron 0.30 mg/1.
Manganese 0.05 mg/1.
Odor 3 Threshold Odor Number.
pH 6.5-8.5
Sulfate 250 mg/1.
TDS (Total Dissolved Solids) 500 mg/1.
Zinc 5 mg/1.
SAMPLING RESPONSIBILITY AND TECHNIQUES
Sampling and testing of public water systems and the interpretation
of the results is a vilal part of the operation. The water purveyor is
responsible for arranging for all of the sampling requirements listed in
which
the Primary Regulations/are applicable to the particular water supply
system. The operator must arrange for the examination of the samples at a
laboratory approved by the State agency. Consult the State agency for
advice and details.
The operator must perform certain tests for operational information,
particularly the chlorine residual test. Chapter9 on Chlorination
discusses the chlorine residual test. This test may be performed by the
operator using commercial test kits, purchased from the manufacturer of the
chlorination equipment or firms which deal in water laboratory supplies. A
list of such firms may be obtained from the State agency. Other tests may
be necessary for plant operation. Tests to measure the pH are also avail-
able through water laboratory supply firms and are inexpensive. If treat-
ment other than chlorination is practiced, the manufacturer or supplier will
recommend the tests necessary to insure proper operation of the equipment.
12-22
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Some State agencies require that water systems employing chlorination
or other required treatment must employ operators who meet minimum qualifica-
tions. Some provide training courses. Consult with the State agency for
details.
Sampling Techniques
Only sampling containers furnished by the approved laboratory should
be used. This is necessary to insure proper cleaning and sterilization
(where necessary) of containers. The laboratory cannot distinguish between
contaminated water in the system and inadvertently contaminated containers
or for that matter contamination from poor sampling techniques. The
importance of good techniques cannot be overstressed.
Sampling taps should be strategically located to facilitate sampling.
Special taps are advisable where sampling must be done routinely. Taps
should be kept clean (may be covered where necessary with a clean paper cup
or plastic bag), and should be free flowing without slop. The tap should be
directed downward so that water does not leak or slop around the outside of
the tap. This is particularly important for samples collected for bacteriolo-
gical examination. Mixing faucets and rubber hose attachments must be avoided.
The tap should be flushed for a sufficient period of time to allow
clearing of the water which may have been standing for a long time. Taps
with short service lines or in heavy use areas are preferred. The sampling
container should be filled to a paint a about 1/2" below overflow. When filling
containers, do not allow water entering the container to contact the hands.
Sterile containers for bacteriological examination should never be rinsed.
On the other hand, it is advisable to rinse sampling containers used for che-
mical and physical tests with some of the water to be tested. This improves
reliability. Containers should be sealed immediately after collection with
the cap provided by the laboratory. Do not inadvertently contaminate the caps.
It is best to hold it in one hand by the top while collecting the sample.
12-23
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Samples collected for coliform bacteria testing should be delivered to
the laboratory within 1 hour if possible. Temporary storage in a refrigerator
is acceptable. In no case should the time lapse between collection and
testing exceed 30 hours.
Certain chemical substances change significantly, particularly when
exposed to air. The following tests should be performed immediately upon
collection to insure reliable results.
- Chlorine residual
- pH and carbon dioxide
- Alkalinity and acidity
- Dissolved oxygen
12-24-
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CHAPTER 13
MAINTENANCE
Pumps - Controls - Treatment Equipment - Distribution
Systems - Well Yield Rehabilitation
INTRODUCTION
Planned, preventive maintenance is essential to the proper operation
of a water system. It is Important not only to insure a reliable safe
water at all times, but also to protect the capital investment and insure
efficient operation. A planned maintenance program pays off in less
frequent interruptions of service and fewer consumer complaints.
Since continuity of service is essential, the water purveyor should
have on hand, or otherwise readily available, the specialized tools and
replacement equipment or parts necessary to maintain and repair the
various component parts of the system.
A schedule for routine preventative maintenance should be prepared
for each pump, control, major valve, treatment unit, and other equipment.
Employees should be instructed to follow the schedule and make pertinent
notations and reports. The schedule need not be complex and can generally
be prepared from the manufacturers instruction sheets.
Installation and operation manuals, supplied by manufacturers, for
pumps, pressure pneumatic systems and controls, chemical feed equipment,
and other devices should be filed for future reference. Schematic plans
and as-built construction plans should be kept up to date and filed.
Location of all underground facilities (pipes, valves, etc.) should be
referenced to permanent markers, curbs, building corners, etc. for quick
location when necessary in an emergency. Maintenance charts should be
kept for equipment which may require periodic lubrication. Replacement
fuses should be available for all fused electrical controls.
13-1
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MAINTENANCE OF WELL PUMPS AND CONTROLS
Small water systems are usually not complex and often consist of
well sources with the associated pumps, hydropneumatic systems and per-
haps a hypo-chlorinator for disinfection of the water with chlorine
solutions. The Water Systems Council has published a handbook entitled
Water Systems Handbook which is particularly useful to the operators of
small systems. The operation and servicing sections are particularly
good. Copies may be obtained from the Council at 221 North LaSalle Street,
Chicago, Illinois 60601. The Council has kindly given permission for the
use of selected portions of their Handbook in this manual.
Servicing Instruments and Test Procedures
Pumps and controls are generally powered by electrical energy. For
that reason, effective maintenance requires a working knowledge of elec-
trical circuits and circuit testing instruments. It is not implied that
every water system operator should be expected to service the electrical
circuits involved in pumps and controls. Electricians and pump service
companies are readily available to perform these services. However, the
operator will do well to understand the basics, if for no other reason than
to learn how to avoid electric shocks.
Jet Pumps
The jet pump is one of the most popular well pumps, particularly for
the small systems. The charts that follow were taken from the Water Systems
Handbook and are intended as trouble shooting guides.
(1) See Appendix C for other manuals and handbooks.
13-2
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Table 13-1: TROUBLE SHOOTING THE JET PUMP
A —PUMP WON'T START OR RUN
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Blown fuse.
Check to see if fuse is OK
If blown, replace with fuse of
proper size
2. Low line voltage.
Use voltmeter to check pressure
switch or terminals nearest pump
If voltage under recommended
minimum, check size of wiring
from main switch on property If
OK, contact power company I
3. Loose, broken, or
incorrect wiring.
Check wiring circuit against dia-
gram See that all connections
are tight and that no short circuits
exist because of worn insulation,
crossed wire, etc
Rewire any incorrect circuits |
Tighten connections, replace de- g
fective wires j
4. Defective motor.
Check to see that switch is
closed
Repair or take to motor service
station
5. Defective pressure
switch.
Check switch setting Examine
switch contacts tor dirt or exces-
sive wear
Adjust switch settings Clean con-
tacts with emery cloth it dirty
6. Tubing to pressure
switch plugged.
Remove tubing and blow Ihrough
it
Clean or replace if plugged j,
4
7. Impeller or seal.
Turn off power, then use screw-
driver to try to turn impeller or
motor
If impeller won't turn, remove
housing and locate source o'
binding
8 Defective start
capacitor.
Use an ohmmeter to check re-
sistance across capacitor Needle
should jump when contact is
made No movemenl means an
open capacitor, no resistance
means capacitor is shorted
Replace capacitor or take motor
to service station
9. Motor shorted out.
If fuse blows when pump is start-
ed (and external wiring is OK)
motor is shorted
Replace motor t
I
B — MOTOR OVERHEATS AND
OVERLOAD TRIPS OUT
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Incorrect line voltage.
Use voltmeter to check at pres-
sure switch or terminals nearest
pump
If voltage under recommended
minimum, check size of wiring
from main switch on property If
OK, contact power company
2. Motor wired Incorrectly.
Check motor wiring diagram
Reconnect for proper voltage as
per wiring diagram
3. Inadequate ventilation.
Check air temperature where
pump is located If over 100°F ,
overload may be tripping on ex-
ternal heat
Provide adequate ventilation or
move pump
4. Prolonged low pressure
delivery.
Continuous operation at very low
pressure places heavy overload
on pump This can cause over-
load protection to trip
Install globe valve on discharge
line and throttle to reduce flow
and to increase pressure
-------
C —PUMP STARTS AND STOPS TOO OFTEN
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT j
1. Leak In pressure tank.
Apply soapy water to entire sur-
face above water line If bubbles
appear, air is leaking from tank
Repair leaks or replace tank j
2. Defective air volume control.
This will lead to a waterlogged
tank Make sure control is operat-
ing properly II not, remove and
examine for plugging
Clean or replace defective control j
Add air as needed. J
3. Faulty pressure switch.
Water Jogged tank
Check switch setting Examine
switch contacts for dirt or exces-
sive wear
Adjust switch settings Clean con- !
tacts with emery cloth il dirty 5
j
4. Leak on discharge side of
system.
Make sure all fixtures in plumb-
ing system are shut off Then
check all units (especially ball-
cocks) for leaks Listen for noise
of water running.
Repair leaks as necessary
5. Leak on suction side of
system.
On shallow well units, install pres-
sure gauge on suction side
On deep well systems, attach a
pressure gauge to the pump
Close the discharge line valve
Then, using a bicycle pump or
air compressor, apply about 30
psi pressure to the system If the
system will not hold this pressure
when the compressor is shut off,
there ts a leak on the suction
side
Make sure above ground connro- 1
tions are tight Then repeat tr^t
If necessary, pull piping and t >
pair leak j
6. Leak in foot valve.
Pull piping and examine foot
valve
Repair or replace defective valv ]
1
D —PUMP WON'T SHUT OFF
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Wrong pressure switch
setting or setting "drift."
Lower switch setting If pump
shuts off, this was the trouble
Adjust switch to proper selling
2. Defective pressure switch.
Arcing may have caused switch
contacts to "weld" together in
closed position Examine points
and other parts of switch tor de-
fects
Replace switch if defective
3. Tubing to pressure
switch plugged.
Remove tubing and blow through
it
Clean or replace if plugged
4. Loss of prime.
When no water is delivered, check
prime of pump and well piping
Reprime if necessary
5. Low water level in well.
Check well wata? against pump
performance table to make sure
pump and ejector are properly
sized
If undersized, replace pump or
ejeclor
6. Plugged ejector.
Remove ejector and inspect.
Clean and reinstall if dirty
-------
E —PUMP OPERATES BUT DELIVERS LITTLE OH
NO WATER
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Low line voltage.
Use voltmeter to check at pres-
sure switch or terminals nearest
pump
If voltage under recommended
minimum, check size of wiring
from main switch on property If
OK, contact power company
2. System Incompletely primed.
When no water is delivered, check
prime of pump and well piping
Reprime if necessary
3. Air lock In suction line.
Check horizontal piping between
well and pump. If it does not
pitch upward from well to pump,
an air lock may form
Rearrange piping to eliminate a.
lock j
4. Undersized piping.
If system delivery is low, the dis-
charge piping and/or plumbing
lines may be undersized Re-
figure friction loss
Replace undersized piping or m ¦
stall pump with higher capacity
S. Leak In air volume control
or tubing.
Disconnect air volume control
tubing at pump and plug hole
If capacity increases, a leak exists
tn the tubing of control
Tighten all fittings and replar.3
control if necessary
6. Pressure regulating valve
stuck or Incorrectly set.
(Deep well only)
Check valve setting Inspect valve
for defects
Reset, clean, or replace valve as
needed
7. Leak on suction side of
system.
On shallow well units, install pres-
sure gauge on suction side On
deep well systems, attach a pres-
sure gauge to the pump Close
the discharge line valve Then,
using a bicycle pump or air com-
pressor, apply about 30 psi pres-
sure to the system If the system
will not hold this pressure when
the compressor is shut off, there
is a leak on the suction side
Make sure above ground connec-
tions are tight Then repeat test
If necessary, pull piping and re-
pair leak
!
8. Low well level.
Check well depth againsl pump
performance table to make sure
pump and ejector are properly
sized
If undersized, replace pump or i
ejector 3
9. Wrong pump-ejector
combination.
Check pump and ejector models
against manufacturer's perform-
ance tables
Replace ejector if wrong model s
being used
10 Low water level in well.
Shut off pump and allow well to
recover Restart pump and note
whether delivery drops after con-
tinuous operation
If well is "weak, lower ejector
(deep well pumps), use a tail pipe
(deep well pumps), or switch from
shallow well to deep well equip-
ment
11. Plugged elector.
Remove ejector and inspect
Clean and reinstall if dirty
12. Defective or plugged foot
valve and/or strainer.
Pull foot valve and inspect Partial
clogging will reduce delivery
Complete clogging will result in
no water flow A defective foot
valve may cause pump to lose
prime, resulting in no delivery
Clean, repair, or replace as need-
ed
13. Worn or defective pump
parts or plugged Impeller.
Low delivery may result from wear
on impeller or other pump parts
Disassemble and inspect
Replace worn parts or entire j
pump Clean parts if required |
i
-------
Submersible Well Pumps
Submersibles have gained favor because of their simplicity
of operation and reliability. Proper servicing requires the
use of certain electric instruments such as the voltmeter,
ammeter and ohmmeter. With these instruments, the cause of
trouble can be often pinpointed without pulling the pump
unit. The six charts that follow are taken from the Water
Systems Handbook and are said to cover 95$ more of pro-
blems which may cause trouble in operation.
13-6
-------
TABLE S3 -2: TROUBLE SHOOTING THE SUBMERSIBLE PUMP
A —FUSES BLOW OR CIRCUIT BREAKER TRIPS
WHEN MOTOR IS STARTED
CAUSE OF TROUBLE
| HOW TO CHECK
HOW TO CORRECT <]
1. Incorrect line voltage.
Check the line voltage terminals
in the control box (or connection
box in the case of the 2-wire mod-
els) with a voltmeter. Make sure
that the voltage is within the mini-
mum-maximum range prescribed
by the manufacturer
If the voltage is incorrect. conSati £
the power company to have it $
corrected.
2. Defective control box:
a. Defective wiring.
Check out all motor and power-
line wiring in the control box, fol-
lowing the wiring diagram found
inside the box See that all con-
nections are tight and that no
short circuits exist because of
worn insulation, crossed wires,
etc
Rewire any incorrect circuits
Tighten loose connection Re- {
place worn wires. !f
i*
tJ
b. Incorrect components.
Check all control box components
to see that they are the type and
size specified for the pump in the
manufacturers' literature. In pre-
vious service work, the wrong
components may have been in-
stalled
Replace any incorrect component >
with the size and type recom- b
mended by the manufacturer. '
j
r
c. Detective starting capaci-
tor (skip for 2-wire mod-
els).
Using an ohmmeter, determine
the resistance across the starting
capacitor When contact is made,
the ohmmeter needle should jump
forward, and then drift back slowly.
No movement indicates an open
capacitor (or detective relay
points), no resistance means that
the capacitor is shorted
Replace defective starting capaci- ;
i
d. Detective relay (skip for
2-wire models).
Using an ohmmeter. check the
relay coil Its resistance should be
as shown in the manufacturer's
literature Recheck ohmmeter
reading across starting capacitor
With a good capacitor, no move-
ment of the needle indicates de-
fective relay points
If coil resistance is incorrect or jf
points defective, replace relay I
f 3-7
-------
3. Detective pressure switch.
Check the voltage across the pres-
sure switch points If less than
the line voltage determined in "1"
above, the switch points are caus-
ing low voltage by making imper-
fect contact
Clean points with a mild abrasive J
cloth or replace pressure switch j
4. Pump In crooked well.
If wedged into a crooked well, the '
motor and pump may become
misaligned, resulting in a locked
rotor
If the pump does not rotate free- j
ly, it must be pulled and the well 1
straightened 1
5 Oefecllve motor winding or
cable:
a. Shorted or open motor
winding.
Check the resistance of the motor
winding by using an ohmmeter on
the proper terminals in the con-
trol bo* (see manufacturer's wir-
ing diagram) The resistance
should match the ohms specified
in the manufacturer's data sheet
If too low, the motor winding may
be shorted, if the ohmmeter
needle doesn't move, indicating
high or infinite resistance, there is
an open circuit in the motor wind-
ing
If the motor winding is defective— {
shorted or open—the pump must j
be pulled and the motor repaired i
b. Grounded cable or wind-
ing.
Ground one lead of the ohmmeter
onto the drop pipe or well cas-
ing, then touch the other lead to
each motor wire terminal If the
ohmmeter needle moves appre-
ciably when this is done, there is
a ground in either the cable or the
motor winding
Pull the pump and inspect the
cable for damage Replace dam-
aged cable If cable checks OK,
the motor winding is grounded
6. Pump sand locked.
Make pump run backwards by in-
terchanging main and start wind-
ing (black and red) motor leads
at control box Before doing, check
with motor manufacturer to see if
motor can be reversed
Pull pump, disassemble ana
clean Before replacing, make
sure that sand has settled in well
If well is chronically sandy, a sub- 8
mersible should not be used 3
B —PUMP OPERATES BUT DELIVERS LITTLE OR
NO WATER
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT \
1. Pump may be air locked.
Stop and start pump several
times, waiting about one minute
between cycles If pump then re-
sumes normal delivery, air lock
was the trouble
If th;s test fails to correct the I
trouble, proceed as below
2. Water level In well too low.
Well production may be too low
for pump capacity Restrict flow
of pump output, wait for well to
recover, and start pump
If partial restriction corrects trou-
ble, leave valve or cock ai re-
stricted setting Otherwise, lower
pump in well if depth is sufficient
Do not lower if sand clogging
might occur
3. Discharge line check valve In-
stalled backward.
Examine check valve on dis-
charge line to make sure that ar-
row indicating direction of flow
points in right direction
Reverse valve if necessary
4. Leak In drop pipe.
Raise pipe and examine for leaks
Replace damaged section of drop
pipe
5. Pump check valve Jammed by
drop pipe.
When pump is pulled after com-
pleting "4" above, examine con-
nection of drop pipe to pump out-
let If threaded section of drop
pipe has been screwed in too far,
it may be jamming the pump's
check valve in the closed position
Unscrew drop pipe and cut off V
portion of threads |
f.
-------
6. Pump Intake screen blocked.
The intake screen on the pump
may be blocked by sand or mud
Examine
Clean screen, and when reinstall- '
ing pump, make sure that it is lo-
cated several feet above the well
bottom—preferably 10 feet or
more
7. Pump parts worn.
The presence of abrasives in the
water may result in excessive
wear on the impeller, casing, and
other close-clearance parts Be-
fore pulling pump, reduce setting
on pressure switch to see if pump
shuts off. If it does, worn parts
are probably at fault
Pull pump and replace worn com-
ponents
8. Motor shaft loose.
Coupling between motor and
pump shaft may have worked
loose Inspect for this after pull-
ing pump and looking for worn
components, as in "7" above
Tighten all connections, set-
screws, etc 1
C —PUMP STARTS TOO FREQUENTLY
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Pressure switch detective or
out of adjustment.
Check setting on pressure switch
and examine ;or defects
Reduce pressure setting or re- ;
place switch |
2. Leak In pressure lank above
water level.
Apply soap solution to entire sur-
face of tank and look for bubbles
indicating air escaping
Repair or replace tank ]
a
3. Leak In plumbing system.
Examine service line to house and
distribution branches for leaks
Repair leaks
4. Discharge line check valve
leaking.
Remove and examine
Replace if defeclive
5. Air volume control plugged.
Remove and inspect air volume
control
Clean or replace
6. Snifter valve plugged.
Remove and inspect snifter valve
Clean or replace
D — FUSES BLOW WHEN MOTOR IS RUNNING
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT §
1. Incorrect voltage.
Check line voltage terminals in
the control box (or connection
box in the case of 2-wire models)
with a voltmeter Make sure that
the voltage is within the mini-
mum-maximum range prescribed
by the manufacturer
If voltage is incorrect, contaci \
power company for service
2. Overheated overload protec-
tion box.
If sunlight or other source of heat
has made box too hot, circuit
breakers may trip or fuses blow
If box is hot to the touch, this
may be the problem
Ventilate or shade box, or remove
from source of heat
3. Detective control box compo-
nents (skip this for 2-wlre
models).
Using an ohmmeter, delermine
the resistance across the running
capacitor When contact is made,
the ohmmeter needle should jump
forward, and then drift back slowly
No movement indicates an open
capacitor (or defective relay
points), no resistance means that
the capacitor is shorted
Using an ohmmeter, check the
relay coil Its resistance should be
Replace defective components
- ?
-------
as shown in the manufacturer's
literature Recheck ohmmeter
reading across running capacitor
With a good capacitor, no move-
ment of the needle indicates re-
lay points
4. Defective motor winding or
cable.
Check the resistance of the motor
winding by using an ohmmeter
on the proper terminals in the
control box (see manufacturer s
wiring diagram) The resistance
should match the ohms specified
in the manufacturer's data sheet
if too low, the motor winding may
be shorted, if the ohmmeter nee-
dle doesn t move, indicating high
or infinite resistance, there is an
open circuit in the motor winding
Ground one lead of the ohmmeter
onto the drop tine or well casing,
then touch the other lead to each
motor wire terminal If the ohm-
meter needle moves appreciably
when this is done, there is a
ground in either the cable or the
molor winding
If neither cable or winding is de-
fective—shorted, grounded, or
open—pump must be pulled and
serviced
|
5. Pump becomes sand-locked.
If the fuses blow while the pump
is operating, sand or grit may
have become wedged in the im-
peller, causing the rotor to lock
To check this, pull the pump
Pull pump, disassemble, and i
clean Before replacing, make j
sure that sand has settled in well j
If well is chronically sandy, a sub- |
mersible should not be used 1
E —PUMP WON'T SHUT OFF
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT |
1. Defective pressure switch.
Arcing may have caused pressure
switch points to "weld" in closed
position Examine points and
other parts of switch for defects
Clean points or replace switch jj
2. Water level In well too low.
Well production may be too low
for pump capacity Restrict flow
of pump output, wait for well to
recover, and start pump
If partial restriction corrects trou-
ble, leave valve or cock al re-
stricted setting Otherwise, lower
pump in well if depth is sufficient
Do not lower if sand clogging
might occur
3. Leak In drop line.
Raise pipe and examine for leaks
Replace damaged section of drop
pipe
4. Pump parts worn.
The presence of abrasives in the
water may result in excessive
wear on the impeller, casing, and
other close-clearance parts Be-
fore pulling pump, reduce setting
on pressure switch to see if pump
shuts off If it does, worn parts
are probably at fault
Pull pump and replace worn com-
ponents
F—MOTOR DOES NOT START,
DON'T BLOW
BUT FUSES
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Overload protection out
Check fuses or circuit breaker to
see that they are operable
If fuses are blown. rep!?ce It
breaker is tripped, reset
^. /j
-------
2. No power.
Check power supply to control
box (or overload protection box)
by placing a voltmeter across in-
coming power lines Voltage
should approximate nominal line
voltage
If no power is reaching box. con-
tact power company for service
3. Defective control box.
Examine wiring in control box to
make sure all contacts are tight.
With a voltmeter, check voltage at
motor wire terminals If no voltage
is shown at terminals, wiring is
defective in control box
Correct faulty wiring or tighten
loose contacts
4. Defective pressure switch.
With a voltmeter, check voltage
across pressure switch while the
switch is closed If the voltage
drop is equal to the line voltage,
the switch is not making contact
Clean points or replace switch
)!
-------
Reciprocating Pumps
Although the reciprocating pump is rapidly being replaced
"by more efficient jet, submersible or turbine pumps,
some are still in use. The following trouble shooting
charts are taken from the Water Systems Handbook.
13-12
-------
TABLE/3-3: TROUBLE SHOOTING THE RECRIPROCATING PIMP
A —PUMP WONT START OR RUN
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Blown fuse.
Check to see if fuse is OK
If blown, replace with fuse of
proper size
2. Low line voltage.
Wtth pump motor energized, use
voltmeter to check at pressure
switch terminals nearest pump
If voltage is under recommended
minimum, check size of wiring
from main switch on property If
OK, contact power company
3. Loose, broken, or Incorrect
wiring.
Check wiring circuit against dia-
gram See that all connections are
tight and that no short circuits
exist because of worn insulation,
crossed wires, etc.
Rewire any incorrect circuits
Tighten connections, replace de-
fective wires
4. Defective pressure switch.
Check switch setting Examine
switch contacts for dirt or exces-
sive wear
Adjust switch settings Clean con-
tacts with emery cloth it dirty |
5. Tubing to pressure switch
plugged.
Remove tubing and blow through
it
Clean or replace if plugged I
6. Pump mechanically bound.
Turn off power, turn pump by
hand
Locate source of binding and re- j
pair i
7. Defective starl capacitor.
Disconnect capacitor from motor
Use an ohmmeter to check resist-
ance across capacitor Needle
should jump when contact is
made No movement means an
open capacitor, no resistance
means capacitor is shorted
Replace capacitor or take motor
to service station
B. Motor shorled out.
If fuse blows when pump is started
(and external wiring is OK), motor
is shorted
Replace motor
9. Overload protector cut out.
Check manual reset overload
Correct cause of overload reset
overload
B —PUMP RUNS BUT DELIVERS NO WATER
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Low line voltage.
With pump motor energized, use
voltmeter to check at pressure
switch terminals nearest pump
If voltage is under recommended
minimum, check size of wiring
from main switch on property If
OK, contact power company
2. Loss of prime (piston pumps).
When no water is delivered, check
prime of pump and well piping
Reprime if necessary
3. Broken rod (working heads).
Disconnect rod from pump head
and see if it can be lifted easily
If rod is broken, remove upper
part Then fish for lower part or
pull drop pipe Repair break
4. Low well level.
On piston pumps, make sure water
level is no more than 25 feet be-
low pump (less if at elevated alti-
tudes)
On working heads, lower well cylin-
der by adding more drop pipe and
rod If this results in water delivery,
cylinder was above water level
If water level is below 25 feet, pis-
ton pump won't work Replace
with submersible or deep well jet
pump
Leave cylinder at lower level
5. Air lock In suction line
(piston pumps).
Check horizontal piping between
well and pump If it does not pitch
upward, an air lock may form
Rearrange piping to eliminate air
lock
6. Suction valves stuck In open
position (piston pumps).
Remove cover from water end of
pump and inspect va'ves
Clean out any foreign matter be-
tween valves and valve plate
Make sure a watertight closure
can occur
-------
7. Leah In suction line (piston
pumps or drop pipe working
heads).
On piston pumps, install a vacuum
gauge on the suction side and start
pump Low vacuum means a leaky
suction line
On working heads, attach a pres-
sure gauge to the discharge line,
upstream of the mam valve Close
the valve Then using a bicycle
pump or air compressor, apply
about 30 psi of air pressure to the
system If this pressure isn't held,
there is a leak in the drop pipe
Repair leaks as necessary J
Repair leaks as necessary j
8. Open foot valve (piston pumps)
or cylinder check valve (work-
ing heads).
Fill drop pipe or suction line with
water If the water level drops, the
lower valve may be defective Pull
drop pipe and inspect foot valve
(piston pumps) or cylinder check
valve (working heads)
Clean, repair or replace as neces- 5
sary jj
U
i
9. Clogged drive point.
If drive point was used in well,
pull suction line and examine
Clean drive point and re-install 1
r
1
C —LOW CAPACITY
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Undersized piping.
If system discharge is low, the
discharge piping and/or plumbing
lines may be undersized Re-
figure friction loss
Replace undersized piping or in- i
stall pump with higher discharge j
pressure 1
2. Low well capacity.
Stop pump and allow well to re-
cover Re-start pump and note
whether delivery drops after con-
tinuous operation
(On working head units, low well
capacity is indicated by a violent
jarring of the drop pipe after con-
tinuous operation This indicates
that air is entering the well
cylinder)
If possible, lower suction line or I
well cylinder to permit greater I
draw-down
f
1
!
d
3. Leaky relief valve
(piston pumps).
Examine built-in relief valve for
defects
If relief valve is leaking, repair or jj
replace .
4. Worn parts.
On piston pumps, examine valves
and valve plate, plunger leathers,
and gaskets
On working head units, pull rod
and examine leathers
Replace worn or defective parts jj
D —PUMP LOSES PRIME (Piston Only)
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT |
1. Suction valves stuck In open
position.
Remove cover from water end of
pump and inspect valves
Clean out any foreign matter be- 1
tween valves and valve plate
Make sure a watertight closure
can occur
2. Leak In suction line.
On piston pumps, install a vacuum
gauge on the suction side and start
the pump Low vacuum means a
leaky suction line
On working heads attach a pres-
sure gauge to the discharge line,
upstream of the mam valve Close
Repair leaks as necessary jj
!
5
Repair leaks as necessary j
i> - / 7
-------
the valve Then using a bicycle
pump or air compressor, apply
about 30 psi of air pressure to the
system If this pressure isn't held,
there is a leak in the drop pipe
3. Defective relief valve.
Examine built-in relief valve for
defects
If relief valve is leaking, repair or
replace
E —PUMP STARTS AND STOPS TOO OFTEN
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT \
1. Leak in pressure tank.
Apply soapy water to entire sur-
face above water line If bubbles
appear, air is leaking from tank
Repair leaks or replace tank |
|
2. Defective air volume control.
This will lead to a water-logged
tank Make sure control is operat-
ing properly If not, remove and
examine lor plugging
9
Clean or replace defective control
y
3. Faulty pressure switch.
Remove tubing and blow through
it
Clean or replace if plugged
4. Leak on discharge side of
system.
Make sure all fixtures in plumbing
system are shut off Then check
all units (especially ballcocks) for
leaks Listen for noise of water
running
Repair leaks as necessary
|
5. Leak in suction line (piston
pumps) or drop pipe
(working heads).
On piston pumps, install a vacuum
gauge on the suction side and
start pump Low vacuum means
a leaky suction line
On working heads, attach a pres-
sure gauge to the discharge line,
upstream of the main valve Close
the valve Then using a bicycle
pump or air compressor, apply
about 30 psi of air pressure to the
system If this pressure isn't held,
there is a leak in the drop pipe
Repair leaks as necessary
Repair leaks as necessary
6 Leak in foot valve
(piston pumps).
Fill drop pipe or suction line with
water If the water level drops, the
lower valve may be defective Pull
drop pipe and inspect foot valve
(piston pumps) or cylinder check
valve (working heads)
Clean, repair or replace as neces-
sary
!
F —PUMP WONT SHUT OFF
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Wrong pressure switch setting
or setting "drift".
Lower switch setting If pump
shuts off, this was the trouble
Adjust switch to proper setting
2. Defective pressure switch.
Arcing may have caused switch
contacts to "weld" together in
closed position Examine points
and other parts of switch for de-
fects
Replace switch if defective
3. Tubing to pressure
switch plugged.
Remove tubing and blow through
it
Clean or replace if plugged
4. Loss of prime (piston pumps).
When no water is delivered, check
prime of pump and well piping
Re-prime if necessary
/3-JS
-------
5. Low well level.
On piston pumps, make sure water
level is no more than 25 feet be-
low pump (less if at elevated alti-
tudes)
On working heads, lower well
cylinder by adding more drop pipe
and rod If this results in water
delivery, cylinder was above water
level
If water level is below 25 feel,
piston pump won't work Replace
with submersible or deep wel' jet
pump
Leave cylinder at lower level
G —EXCESSIVE OPERATING NOISE
CAUSE OF TROUBLE
HOW TO CHECK
HOW TO CORRECT
1. Water-logged tank or air
chamber.
Make sure control is operating
properly If not, remove and ex-
amine for plugging
Clean or replace defective cont'o1
i
2. Undersized suction line
(piston pumps).
Check manufacturer's recommen-
dations for sizing suction line
Replace with larger diame'c ¦'
suction line is undersized
3. Sticking suction valves
(piston pumps).
Remove cover from water end of
pump and inspect valves
Clean out any foreign matter ¦ <
tween valves and valve p'r •
Make sure a watertight closure can
occur
4. Rod slapping against drop pipe
(working heads).
Feel rod for "play", especially if
it's made of steel
Install rod guides at 10 foot ei- j
vals, or replace steel rod witn
wood |
5. Low well level.
On piston pumps, make sure
water level is no more than 25 feet
below pump (less if at elevated
altitudes)
On working heads, lower well
cylinderby adding more drop pipe
and rod If this results in water de-
livery, cylinder was above water
level
If water level is below 25 foot j
piston pump wun't woik Replace
wilh submersible or deep well jet
pump
Leave cylinder at lower level '
6. Sticking or noisy cylinder
valves (working heads).
Pull cylinder and examine valves
If valves operate sluggishly in-
stall cylinder with springloadeci
vjlves 11 noise is the problem
switch to a cylinder with ruboer-
faced valves j
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Centrifugal Pumps
Centrifugal pumps may be single or multiple stage
depending upon the desired discharge pressure. They are
usually mounted on the floor of a pump station. The driving
mechanism is usually an electric motor although gas engine
auxiliary drive is possible. They come in "both oil and
water lubricated types. Care should be taken to lubricate
in accordance with manufacturers recommendations.
Centrifugal pumps may require periodic priming if they
do not operate under a positive pressure on the intake side.
Check valves or foot valves on the intake are necessary to
protect against loss of prime. The pumps are also prone to
air binding and are often provided with manual or automatic
vent valves on top of the pump casing. If the pump requires
priming, only safe, clean water must be used. Ejectors or
vacuum pumps are also available to facilitate priming.
Turbine - Vertical Shaft - Pumps
Vertical - drive turbine pumps may consist of one or
more stages (bowls) submerged below the drawndown water
level in a well casing. The drive unit (most often an
electric motor but capable of gas engine auxiliary drive
by means of a side power take-off) is mounted over the
casing. A vertical shaft conveys power from the drive motor
to the pumping unit. Unlike the submersible pump, a pump
house is required to house the unit. The weight of the shaft
and pump unit is usually suspended by a thrust bearing
located in the pump head. The bearings may be lubricated
by oil or water, depending upon the design. The water
13-17
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lubricated types are preferred from a sanitary point of view
as oil may leak into the casing and contaminate the water,
particularly if over lubrication occurs. Care should be
taken to prevent over oiling.
The well casing should extend above the floor of the
pump house 8 inchsor more to prevent floor drainage from
entering the casing. Care should be taken when flushing the
floor to prevent slop over to the casing.
Turbine pumps are self priming.
Hydro-pneumatic System and Controls
Pressure tank systems have four essential components:
pump - tank - pressure controls and - air controls.
Pressure controls usually have an adjustable feature for
cut in pressure and the pressure operating range. An
occasional re-adjustment may be necessary. A spare pressure
switch should be on hand or readily available for emergency
replacement.
Air controls should be selected for the prevailing
conditions. The purpose of the air control is to maintain a
predetermined amount of air in the pressure tank. The air
serves as a means of storing energy to provide water to meet
short term peak demands and avoid too frequent on and off
operation of the pump. Air can be absorbed by the water in
the tank or on some occasions, excess air or gases are
introduced into the tank with the water. Air controls can
be the - air add type, - the air release type or - the
constant air charge type. Some tanks provide a physical
13-18
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separation of air and water, but these are usually limited
to rather small tanks. Regular checks should be made to
insure that the air control is performing properly. Manu-
facturers directions should be followed.
It is advisable to provide a pressure relief valve in
the system as an added precaution where high pressure pumps
are used, such as positive displacement pumps or multi stage
submersibles or turbine pumps. The relief valve should be
set below the pressure tank safe operating pressure and
should be located on the tank or discharge piping. The
relief valve should be large enough to relieve the rated
capacity of the pump and should be piped to a drain. The
valve should be checked periodically to make sure it is not
stuck.
Protection of Electrical Components and Shock
The principle cause of electric motor failure is over-
heating (resulting in insulation failure) caused by over-
loading, a locked rotor, rapid recycling or loss of cooling
due to clogged or impeded ventilation or low water level in
a submersible pump casing. Protection devices are installed
in motor cirucits to shut off the power when overheating occurs.
Some motors are protected by a combination thermostat and
overcurrent protector located in the motor. Other
13- I?
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motors (summersibles) may have external as well as internal
protective devices. Low water protectors are also often
installed in wells to protect against pump operation when
the water level falls below a predetermined depth. The
operator should become familiar with all of these devices
and must know where and how to reset them, after.locating
the problem (if any) causing the tripping of the circuit.
Consideration should be given to the installation of
devices to protect valuable electrical equipment from
electrical overloads due to lightning. Consult the local
power company for advice. This becomes more important in
areas subject to frequent electrical storms (See Chapter 6).
Guages
Guages are available both as indicating or with
recording mechanisms. Recording guages provide a per-
manent record of the system's operation. However, recording
pens must be re-inked and chart paper must be installed on a
routine schedule to obtain continuous readings.
Indicating guages and pressure switches are usually
trouble-free if properly installed. However, scales,
deposits, and turbidity can effect the accuracy and opera-
tion of most devices if not looked after and periodically
checked.
The water meter is another important control device in
a water system. After some time, normal wear and deposits
may cause the meter to record less than the actual amount
13-20
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of water passing through it. Therefore, it is desirable to
replace, or recalibrate meters at periodic intervals based
on manufacturer's recommendations.
Warning systems and operator alarms should be designed
with a test mode to indicate if the circuits are functioning.
TREATMENT EQUIPMENT
Hypochlorinators and Other Liquid Chemical Feed Pumps
The most widely used treatment device in small public
water systems is the hypochlorinator (chemical feed pump).
Chlorination is widely practiced and is often required by
State enforcing agencies. In addition, chemical feeders for
sequestering agents and corrosion control buffer solutions
are in general use.
All feeders must be routinely cleaned of scale and
serviced to insure effective operation. This is especially
true where chlorination of the water supply is a mandatory
feature to insure a continuous safe supply. Deposits and
scale are more prevalent when calcium hypochlorite rather
than sodium hypochlorite is used as the source of chlorine.
It is further aggravated in areas where the water is hard or
high in dissolved iron. Sodium hypochlorite is preferrable
in all respects. A mild solution (5$) of muriatic or acetic
acid is helpful to remove deposits. The unit should' first
be flushed with water to flush out chlorine solutions. The
acid should not be allowed to come in contact with the
chlorine solutions as free chlorine gas may be produced. The
equipment should be taken apart and serviced at intervals
specified by the manufacturer. A servicirg kit should be on
hand at all tines.
13-21
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Chlorine Gas Chlorinators
Gas chlorinators require special care in installation,
operation and maintenance as chlorine gas is highly toxic
and corrosive. Operator and public protection is absolutely
necessary. The gas chlorinator and chlorine gas supplier
will provide a complete manual for installation, operation
and maintenance.
Water Conditioning Equipment
A variety of water treatment equipment is available to
meet just about any water conditioning problem. These
includes
- Pressure filters (sand and diatomaceous earth)
- Softening to remove har,dness
- Conditioners to remove iron, manganese, sulfur
- Corrosion control
The manufacturer's instructions should be followed to
insure proper operation and maintenance.
DISTRIBUTION SYSTEM
Most of the distribution piping for small community water systems is
underground and usually forgotten unless a main breaks. Surveys for leaks,
periodic flushing, and valve maintenance will help minimize major problems,
retard deterioration, and avoid complaints from consumers.
Leaky joints, splits and breaks require early repair. Repair sleeves
and clamps are semi-circular devices which can be bolted together around
the pipe or joint to stop the leak or cover defects in the pipe. Repair
cla"ip kits for assorted sizes of standard pipe should be readily available
or stocked.
When major leaks occur, they are often firs-: noticed as reduced pres-
sure and Quantity of "water service bv the ccsurer, and in extreme cases
13-22
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no water service at all. Leaks are often followed by an unexpected
increase in water pumped into the system. A mastermeter is essential
to read such trends.
Locating a break can often be a frustrating experience. There are
several simplified methods to aid in leak detection. The easiest method
is to "walk the lines" to locate wet spots which might indicate the
presence of the leak. This method is most useful during dry weather.
Another method is to use listening devices. A steel bar held against t'-p
pipe or valve at various locations will help locate the leak as the sound
of the escaping water will be loudest near the leak. A more sensitive
listening device is a set of geophones. Since geophones are expensive,
it is suggested that one be borrowed or rented if possible. Listening
is best done in the early morning hours when water use is low. A final
method to help locate leaks is to valve off various sections of the distri-
bution system. This is particularly useful for systems which have a master-
meter as the flow rate will be affected immediately as the leaky section is
either valved into or out of service.
In water systems serving restaurants, nursing homes, motels, etc.
leaks in plumbing fixtures can be significant. All faucets and toilet
tanks should be checked. While each fixture may not be leaking a larpe
amount, the accumulated water loss from several leaky fixtures will be
quite significant.
Deposits settle out in water mains where flow patterns have been
unchanged or stagnant for long periods of time. Deposits settle even
when the source is free from apparent turbidity. These sediments can
and often do result in taste, odor and turbidity complaints from consumers.
In addition, incrustations may restrict the water flow within the piping
system. To avoid these problems, it is recommended that a routine
13-23
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flushing program be initiated. Flushing can be accomplished by opening
the blowoff valves or hydrants on the end of each line. Water should be
flushed until it clears. It is recommended that the flushing be done with
advance notice to the consumers in the immediate area or done during the
early morning hours when customer usage is minimal.
In some cases the deposits may become so incrusted that normal
flushing will not improve a low flow condition. In such cases, mechanical
pipe cleaning may be necessary. As the equipment for mechanical cleaning
is expensive and not readily available to rent, a professional pipe
cleaning and restoration service company should be consulted. In many
cases it may be more economical to replace the piping in the effected area.
To isolate parts of the distribution system for leak detection or
flushing, it is necessary that all the valves in the system be in good
working condition. It is important to "exercise" all the valves at least
twice a year. Exercising the valves accomplishes two objectives. Firstly,
it determines whether or not the valve works, and secondly, it helps clean
incrustation from the valve seats and gates. After reopening the valve
fully, back off about a half-turn to help prevent the valve from "freezing".'
Any valves which do not completely close or which leak, or are otherwise
defective, should be replaced.
Sometimes, biological growths (commonly called slime growths) accumu-
late inside pipe walls. The slime growths may add objectionable tastes arid
odors to the water. The growths may occasionally slough off resulting in
turbidity and objectionable slugs of slime. The presence of slimes usually
indicates that an effective chlorine residual is not present throughout the
system. A gradual increase in the chlorine dose is usually effective in
controlling the growths. Heavy doses of chlorine as described in Chapter 11,
Disinfection, is also effective. The disinfection should be followed by
vigorous flushing through hydrants or blowoffs.
13-2M-
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A map of the distribution system showing accurate location of all pipes,,
valves and other appurtenances is essential to proper maintenance. The map
should be updated as new work or repairs are made.
All work done on the distribution system should be logged in the
Maintenance Records (See Chapter 14) for future reference. Special comment,
concerning changes in the appearance, taste, odor or other water quality
indicators should be recorded as should the condition of valves, etc. A
record of water pressures at various locations in the system can provide
clues to loss of pump capacity, leaks or unusual water usage and incrusied
pipes.
CORROSION CONTROL (See Chapter 10)
Corrosion may be a problem both inside and outside of
steel pipes. Cathodic protection of pipelines against corro-
sion is increasingly being used. Two methods are available.
The first method requires that anodes energized by a D.C.
power source be installed in the soil around the pipe to be
protected. The pipe is connected to the negative terminal.
The second method involves the use of galvanic anodes which
in themselves generate current, thus eliminating an outside
power source. Unfortunately, only very low current flov*s are
generated and many galvanic anodes are required, which can be
expensive. In addition, if mechanical joints are used, each
pipe section must be electrically connected or have its own
anode attached.
Asbestos cement pipe and approved plastic pipe offer
built-in corrosion prevention. Since they are both non-conduc-
tors of electricity, they are immune to electrolysis corrosion.
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WELL YIELD REHABILITATION
After a period of time, a well may fail to produce an
adequate supply of water. While there are
reasons for a well to "quit" the main causes are centered
around pump problems, declining water levels, plugged or
corroded screens, or accumulations of sand and mineral
sediments in the well.
Before remedial actions are taken, a proper analysis
should be made to determine the causes. The first step is to
measure the water level in the well before, during, and after
pumping. This should be compared with drawdown tests made
at the time the well was constructed. Well drillers usually
provide a well rehabilitation service.
When the well screen or sand about the screen becomes
clogged with mineral deposits, the yield of the well
decreases. When the decrease becomes significant, cleaning
is required. The use of special acids and other formulated
chemicals to effect the cleaning should be exercised with
great care to prevent unnecessary corrosion of the pumps and
screen and contamination of the well and distribution system.
Manufacturer's instructions on the use of chemicals must be
followed explicitly to avoid problems.
If iron bacterial growths in the well are the problem,
the use of chlorine disinfection may prove helpful. Disin-
fection may be done as described in Chapter 5 except that at
least 300 mg/1 of chlorine dose is recommended. Surging the
well may prove helpful. The process should be repeated at
periodic intervals, based upon experience. After disinfection,
tlje well is pumped to waste to flush out accumulated iron slime.
13-26
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CHAPTER 14
RECORD KEEPING
Facility Plans - Operation and Maintenance Records
Legal Requirements
INTRODUCTION
A system of record keeping is an essential feature of good public
water system management. Records provide a continuous listing of the
day to day bits of important information on the operation and mainten-
ance of the system. The organized data provides the basis for the
judgments and decisions which are necessary for good management and
provides the basis for accountability to the State regulatory agency
and the public. Organized records have the following broad uses:
- Provides a continuous record of operation and maintenance infor-
mation, including water quantity and quality.
- Serves as a tool to assist in operation and maintenance decisions.
- Serves as a reminder of things which need to be done, materials
and supplies which need to be obtained, preventive maintenance
schedules and repair schedules.
- Provides a means of fulfilling the record keeping and reporting
requirements of the Drinking Water Regulations and the State
regulatory agency. See Chapter 12.
The extent of record keeping will depend upon the volume of water
processed (the number of consumers served), the complexity of the treat-
ment processes and the applicable record keeping requirements under the
EPA and State agencies regulations. The water purveyor should consult
with the State agency for specific requirements and for sample forms to
assist in recording data.
14-1
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Small water supply systems do not need elaborate record systems, but
they must be adequate to meet general purpose and special needs. Simple
ferns with spaces to record data are convenient and also serve as a reminder
of things to be done. Some typical forms are included at the end of this
Chapter and may be used as is or adapted to special needs. Prepared forms
are especially applicable for recording data on plant operation, sampling
and testing and maintenance. In addition, records must be kept of the
actions taken to correct violations of the Drinking Water Regulations.
Copies of written reports and communications relating to sanitary surveys
of the system must also be kept on file.
Records must be kept on file for minimum specified periods of time
(See Chapter 12) and should, therefore, be recorded in ink or ball point.
Records should be filed and retained on the premises or at a location near
the premises for safe keeping and easy retreaval. Properly labeled loose-
leaf notebooks provide an efficient and inexpensive means of storing
records, as do filing cabinets.
Entries should be made on the recording forms by the person responsible
for operation, maintenance, sampling or testing. Entries should be made
promptly to avoid errors or ommissions. Neat and easily read records are
an asset and often reflect the care taken in operation and maintenance.
Tor convenience, records may be classified as Engineering Plans,
Operation Records, Maintenance Records, and Reporting and Public Notiti-
cation Records. Sampling and testing are usually considered part of the
Operation Records.
14-2
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ENGINEERING PLANS AND SPECIFICATIONS
The "as-built" engineering plans and specification used to construct
the water system should be kept up to date to reflect any changes in the
system. If plans do not exist, it will be prudent to prepare a basic set
of plans for permanent record purposes. The plans should include the
following:
- Site plans of the water supply source(s) (wells, etc.) showing the
location and distances to potential sources of pollution as outlined
in Chapter 2 under Sanitary Survey.
- A log of each well
- Well yield test data
- Construction features of each well
- Plans of pump stations, treatment facilities and other appurtenances
- Plans of reservoirs and storage facilities
- Plans of the distribution system showing watermain locations, sizes,
valves, hydrants, blowoffs, sampling points, etc.
- Equipment instruction manuals
OPERATIONAL RECORDS
The amount of operational information needed will depend upon the
amount of water treated, the type and complexity of treatment, and the
extent of other facilities in the system. Each system has critical fea-
tures for which data is necessary or desirable. The following minimum
operational records include the items which may be applicable to small
water systems.
14-3
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General Operating Records
Drawdown and static levels of wells
Pump pressures (input and output)
Pumping hours per day (total hours of operation)
Quantity of water pumped or delivered by gravity per day
Air - water ratio of hydropneumatic tanks
Treatment Records
Amount of water treated per day
Chlorine dosage in mg/1 (ppm)
Total quantity of chlorine used per day (in weight or liquid measure)
Other chemical dosage and quantity per day
Records on the operation of sofeners, filters and other water conditioning units
Record of samples collected (date, time and location)
Results of bacteriological, physical and chemical tests (before and after
treatment, where applicable)
Distribution System Records
Chlorine residual tests, time, location and amount in mg/1 (ppm)
Bacteriological tests
Meter readings at consumer points
Pressures at key locations
Storage reservoir water levels
MAINTENANCE RECORDS
A good system of maintenance record keeping will provide the basis for
preventive work which may obviate emergencies or unscheduled shut-downs.
14-4
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Manufacturers of equipment provide information manuals which should
be retained and used for future reference. The information should include
the following:
- Installation instructions
- Pump characteristics
- Lubrication instructions
- Operating instructions
- Procedures for dismantling and re-assembling
- Parts list and ordering instructions
Electrical motors and controls are used extensively in water systems.
Experience has shown that ninety per cent of motor failures are due to
five causes: dirt, moisture, friction, vibration and overheating. A
routine cleaning schedule will eliminate dirt; anti-moisture precautions
will combat moisture; prudent lubrication will control friction; and proper
alignment and bolt tightening will control vibrations. Cortrol equipment
should also be checked regularly. Overheat and overload controls should be
provided on all electric motors (See Chapter 13).
Lubrication is one of the most important features of a maintenance
program. It cannot be overstressed that the manufacturers' recommendation
should be carefully followed. It is important not to over lubricate parts,
especially electric motor bearings.
As most duties are routine, schedules can be prepared for completion
of the various activities, including the following:
- Lubrication
- Inspection (motors, bearings, pumps, etc.)
- Electrical facilities checks
- General facilities checks (exercising valves, hydrants, etc.)
14-5
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Work done on each piece of equipment should be kept separately. Keeping
records on file cards or in a notebook is simple and effective. Typical
equipment record forms are shown at the end of this Chapter.
LEGAL REQUIREMENTS FOR RECORD KEEPING, REPORTING AND PUBLIC NOTIFICATION
The National Drinking Water Regulations establish minimum requirements
for monitoring, testing, maximum contaminate levels, chlorine residuals (for
disinfection) and the required actions by the owners of public water systems
under specific circumstances. These are summarized in Chapter 12, under the
heading-Reporting, Public Notification and Record Keeping. The water purv-yo-
and the water system operator must become thoroughly familiar with these
requirements and must establish the procedures necessary to insure full com-
pliance .
14-6
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Figure 14-1; EQUIPMENT INSPECTION AND REPAIR RECORD
Name of Equipment
Pertinent Data
Date
Inspection Results and Work Done
Initials
Remarks
Typical Equipment Inspection Sheet
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Figure 1^-2
REPORT ON OPERATION OF HYPO-CHLORINATOR MONTH OF ly
NAME OF ESTABLISHMENT
LOCATION
TYPE AND MANUFACTURER'S NAME
No. of quarts of 5.25% bleach/gallon of water.
SODIUM HYPOCHLORITE SOLUTION STRENGTH quarts/gallon of water
Date
Amount of Water
treated-gallons
or cubic meters
Result
:s of Chlorine Residual
fMe per liter)
Qts. or
Liters of
Solution
Location
Time
Result
Location
Time
Result
1
2
3
4
5
6
7
8
9
I
10
11
12
13
14
15
1
1
16
1
1
17
i
18
19
20
21
22
23
24
25
26
27
28
29
30
31
1
OPERATOR'S SIGNATURE
DATE
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CHAPTER 15
EMERGENCIES AND
SPECIAL PROBLEMS
Planning for Emergencies - Emergency
Disinfection - Cross-connections -
Chemical and Biological Contamination
INTRODUCTION
Not-with-standing careful planning, design, operation
and maintenance, unforseen problems and emergencies occa-
sionally arise which require immediate attention to insure
continuity of water service and a safe water supply at all
times. The purpose of this Chapter is to (1) alert the water
purveyor to some of the potential problems and emergencies
(2) provide some guidance, and (3) to stimulate the water
purveyor to plan ahead for emergencies so that the impact
may be confined and controlled. Supplying water to the public
is a serious responsibility. Before an emergency suddenly
developes and there is a danger of contaminated water or pro-
longed interruption of service, the water operator will do
well to ask himself in advance - "What will I do if?"
- There is a prolonged interruption of electric power.
- A key well pump motor or bearing "burns out."
- A key chlorinaxor or treatment unit fails.
- Flooding occurs with the threat of contamination.
- Tests indicate that the water is contaminated with
micro-organisms of sewage origin, or potentially
harmful chemicals or substances.
- A key watermain ruptures
- Ex cetera
15-1
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If these and other potential emergencies are thought
out in advance, and mitigating procedures are planned in
advance, potentially big emergencies will "become small ones.
Chapter 13 on Maintenance discusses many of the routine
items which ought to be done as preventive maintenance.
Having on hand, or readily available, certain key replace-
ment parts or repair parts is important and should be care-
fully considered.
The National Drinking Water Regulations (Chapter 12) re-
quires certain reporting procedures to the State agency
(and in some cases the public) in the event of contamina-
tion of the water in excess of the established limits. The
water purveyor will do well to also notify the State agency
in the event of other major emergencies, as they will be of
help in advising on how best to overcome the emergency.
This is particularly important if the emergency poses a
-chreat of unsafe water, the need to seek an emergency source
of water or the addition of a chemical to the water. No
matter how dire the emergency, the water purveyor should not
connect an unapproved source of water into the system with-
out the specific approval of the State agency.
EMERGENCY DISINFECTION
In the event of inadvertent or suspected contamination
of the water, the State agency should be notified immediately.
The State agency, after evaluation, may issue a "boil order"
or may require immediate emergency chlorination of the entire
system. The water purveyor will do well to have on hand a
-------
standby chlorinator and established chlorine injection taps
even if the State agency has not required chlorination on a
routine basis. As pointed out in Chapter 9. a standby chlori-
nator which can be put into immediate service, is a good
investment.
If a "boil order" is required, consumers should be
instructed to use one of the following procedures:
1. Boiling. Vigorous boiling of water for 2 minutes
will destroy disease causing bacteria present ir.
water. Boiled water may have a flat taste.
Letting it stand for a few hours or beating with
a clean mixer will add air and improve the taste.
A pinch of salt per quart of water will also help.
2. Chlorine Disinfection. Common household chlorine
bleach is an effective disinfectant. Containers
usually describe disinfection procedures. If not,
read the label to determine the chlorine strength,
and use the following guide:^^
% Chlorine *
Drops per quart of
clear water **
1%
4- 6%
7-10%
10
2
1
* If strength is not known, use 10 drops
** Double amount for dirty or colored water
(f ) Manual of Individual Water Supplies, EPA
15-3
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CROSS-CONNECTIONS
A cross-connection is any physical connection between
(2 )
a potablev ' water supply system and any source of pollu-
tion, whereby the source of pollution can enter into the
I
potable water supply system. It includes, among others,
physical connections between a potable water supply system
and:
- Any waste, soil, sewer or drain pipe
- Any unapproved water source or system
- Any contaminating liquid, gas or solid
- Any potable water outlet which is submerged or can be
submerged in a waste water or any other source of con-
tamination or source of water of questionable safety.
All State regulating agencies prohibit cross-connections
except when and where suitable protective devices approved
by the agency are installed, tested, and maintained to
insure proper operation on a continuing basis. These
devices are generally called back-flow preventers.
The water purveyor should be aware of any conditions
in the water supply system which may result in a cross-
connection and should take such measures as may be necessary
to ensure that the system is protected from contamination,
including the installation of back-flow prevention devices
or the discontinuance of the service, consistent v/ith the
degree of the hazard. Detailed information on cross-connec-
tion control may be obtained from the State agency. An
(2) A water which is intended for human consumption
15-^
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excellent as-u^als Cross-Connection Control Manual , U.S.
rr./ii-CiiiiieriXdi Proxection Agency, may be obtained from the
Superintendent of Docunjenxss U.S. Government Printing
Oii'ice,, V/ashingxon, DuCa 20402<,
i-ublic health records abound with case histories of
i/axer suprjly systems which have become contaminated through
xhe illegal use ox cross-connections, resulting in serious
disease or intoxication wixh xoxic substances. Although
•the dexectior. and dixninaxion of cross-connections may seem
elementary and obvious, they may appear in many subtle
forms and in unsu^pecxed places- They occur all to frequently
for a variexy ox reasons.
~ Plumbing is frequently installed by persons who are
rjiaware of the inherent dangers of cross-connections.
- Crosd-connecxions are often made as a simple matter
of convenience without regard to the dangerous situa-
tion which they create.
- A cross-connection is made with a reliance on a
simple valve or other inadequate mechanical device.
The contamination of a potable water supply system
xhrcugh a cross-connection occurs when the polluted source
exceeds xhe pressure of xhe potable water system. The
octioii is called back-flow. Back siphonage. is a back-flow
which occurs u'hen a negative pressure (partial vacuum) is
created in xhe potable water system. Essentially, the
condition i-: a reversal of hydraulic pressures which may be
voduced b'; a variety of circumstances. It is therefore essen-
xial xhat xhe wesiures throughout the distribution system
b*= mair.ts&ii-tfd a or^sure of not less than 20 psi during peak
fl0Vi .... -0 che cyotrtv.nitv for back siphonage.
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Two basic Types of cross-connection occur in potable
water systems; (l) the direct pipe connection between the
•water supply system and the polluting source, often sepa-
rated by a simple valve and (2) an outlet of the water
supply system which is submerged into a tank, fixture or
device containing potential pollution. Both types are
prohibited, except where and when approved back-flow pre-
venters are installed. Listed below are partial lists of
both types, presented as illustration of potentially
hazardous fixtures.
Table/-fill: PARTIAL LIST OF PLUMBING HAZARDS^
Fixtures with Direct Connections
Air conditioning, air washer-
Air conditioning, chilled water
Air conditioning, condenser water
Air line
Aspirator, laboratory
Aspirator, medical
Aspirator, weedicide and fertilizer sprayer
Autoclave and sterilizer
Auxiliary sysxem, industrial
Auxiliary system, surface water
Auxiliary system, unapproved well supply
Boiler system
Chemical feeder, pot-type
Chlorinator
Coffee urn
Cooling system
Dishwasher
Fire standpipe or sprinkler system
Fountain, ornamental
Hydraulic equipment
Laboratory equipment
Lubricaxion, pump bearings
Photostat equipment
Plumber's friend, pneumatic
Pump, pneumaxic ejector
Pump* prime line
Pump, water operated ejector
Sewer, sanixary
Sewer, sxorm
Swimming pool
(3) From Cross-connection Control Manual, U.S. Environ-
mental Fro-ecuiun Agency
-------
TABLE/5"-l: (Continued)
Fixtures with Submerged Inlets
Baptismal fount
Bathtub
Bedpan washer, flushing rim
Bidet
Brine tank
Cooling tower
Cuspidor
Drinking fountain
Floor drain, flushing rim
Garbage can washer
Ice maker
Laboratory sink, serrated nozzle
Laundry machine
Lavatory
Lawn sprinkler system
Photo laboratory sink
Sewer flushing manhole
Slop sink, flushing rim
Slop sink, threaded supply
Steam table
Swimming pool
Urinal, siphon jet blowout
Vegetable peeler
Water closet, flush tank, ball cock
Water closet, flush valve, siphon jet
Direct, solid pipe connections are often inadvertently
made to continuous or intermittent waste lines where it is
assumed that the flow will always be in one direction. They
are also often installed where it is necessary to supply
water to an auxiliary piping system. Under conditions of
back-flow or back-siphonage, the polluting source can enter
into the potable water supply.
Submerged inlets are found in many common plumbing
fixtures and are often a built-in feature of the fixture.
Modem sanitary design has minimized or eliminated the
hazard in new fixtures. Chemical and industrial process
vats sometimes have submerged inlets where the water
15-7
-------
supply pressure is used as an aid in diffusion, dispersion
or agitation. Back-siphonage is an ever present danger.
Submerged inlets are often found in swimming pools. These
can be readily eliminated by discharging the potable water
(used for filling the pool) at least 2 pipe diameters above
the maximum pool water level.
Wherever possible, it is preferable to eliminate the
cross-connection by removal of the physical link, thus
eliminating the possibility of failure of a mechanical
control device. Where this is not possible, approved con-
trol devices must be used.
CONTAMINATION BY PETROLEUM PRODUCTS
Petroleum products are in such common use that the
inadvertent contamination of water supplies is not uncommon.
Groundwater contamination by petroleum products causes
objectionable taste and odor at extremely small concentrations.
Petroleum products are quite stable and thus not readily de-
composed by bacteria in water or soil. These products may
travel great distancesover a long period of time. The adsorp-
tion potential of soil particles (particularly clay and
organic matter) traps petroleum products, releasing them
gradually and contributing contamination to a water aquifer
over a prolonged period of time.
The water purveyor should be alert for potential situa-
tions which may result in the contamination of the water
system with petroleum products. Over lubrication of pumps,
particularly vertical turbine and other over-the-well pumps,
should be avoided. Furthermore, well casings in pump rooms
15-8
-------
should extend above the floor and should be sealed to prevent
the entry of accidently spilled petroleums or other potentially
harmful materials. It is preferable that these materials not
be stored in well houses. As a matter of safety, they should
not be stored on the ground in the vicinity of wells. Oil
storage tanks used to heat pump rooms have on many occasions
contaminated the ground water in the vicinity of water wells,
from hardly noticeable leaks.
If the well should become contaminated with small quanti-
ties of petroleum products, it may be helpful to add a house-
hold type detergent directly to the well casing. The well
should then be pumped, returning the discharge back into the
casing and washing the inside of the casing. The recycling
will enhance emulsification. Then pump to waste until the
detergent is completely removed. Do not pump the waste in
such a way as to recontaminate the well. If the taste or
odor persists, the State agency should be consulted for advice.
CONTAMINATION WITH OTHER CHEMICALS
Most insecticides, pesticides and herbicides are highly
toxic. All industrial chemicals and radioactive substances
must also be considered toxic. If it is suspected that any
foreign substance has inadvertently (or intentionally) con-
taminated the system, notify the State agency immediately by
the swiftest form of communication for advice. In the mean-
time, notify consumers immediately and, if necessary, shut
down the water system.
15-9
-------
Rock salt and other salts used extensively for road
de-icing, are a potential source of groundwater contamina-
tion, particularly when stored on the surface of the ground
in the vicinity of water wells. The salts are readily dis-
solved by rain and runoff and percolate with the water to
penetrate water aquifers for considerable distances. The
water purveyor should be alert for open storage of salts near
the water source. If the salt storage poses a significant
threat and the owner cannot be persuaded to correct the
situation, or the groundwater aquifer becomes contaminated
with these salts, the State agency should be called for
advise.
15-10
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PART III
APPENDICES
-------
APPENDIX A
GLOSSARY
Selected Water Related Terms
Selected from Glossary of Wacer and Wastewater Control Engineering, 1969
Edition, Prepared by Joint Committee representing:
- American Public Health Association
- American Society of Civil Engineers
- American Water Works Association
- Wacer Pollution Control Federation
ail
ifab<5 ac^ ~ (1) A substance that tends to lose a proton. (2) A substance that
dissolves in wacer with the formation of hydrogen ions. (3) A
substance containing hydrogen which may be replaced by metals to
form sains.
acre-foot - A volume of water 1 foot deep and 1 acre in area, or 43,560
cubic feet.
air and vacuum valve - An air valve which permits entrance of air into an
empty pipe no counteract a vacuum and escape of accumulated air.
Also called vacuum valve.
air-gap separation - The unobstructed vertical distance through the tree
atmosphere between the lowest opening from any pipe or outlet
supplying wacer to a tank, plumbing fixture or other device, and
the flood level rim of the receptacle.
air relief valve - An air valve placed at the summit of a pipeline to
release the air automatically and prevent the pipeline from becoming
air bound with a resulcant increase of pressure.
algae - Primitive plants, one or many celled, usually aquatic, and capable
of elaborating their foodstuffs by photosynthesis.
alkali - Any of certain soluble salts, principally of sodium, potassium,
mangesium, and calcium, that have the property of combining with
acids to form neutral salts and may be used in chemical processes
such as wacer or wastewater treatment.
alkalinity - The capacity of water to neutralize acids, a property imparted
by the water's content of carbonates, bicarbonates, hydroxides, and
occasionally borates, silicates and phosphates. It is expressed in
milligrams per liter of equivalent calcium carbonate.
altitude-control valve - A valve that automatically shuts off the flow when
the water level in a water storage tank reaches a predetermined
elevation and opens when the pressure on the system side is less than
that on the tank side.
i-l
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aquifer - A poroaa, water bearing geologic formation,, Generally re-
stricted to materials capable of yielding an appreciable supply
of water;
artesian aquifer - An aquifer confined between less permeable materials
from which i/ater will rise above the bottom of the overlying con-
fining bed if afforded an opportunity to do so. Also called
confined aquifer.
artesian flowing well - A flowing well in which water is lifted above the
land surface by hydrostatic pressure„
artesian spring - A spring in which water issues under pressure through
some fissure or other opening in the confining formation above the
aquifer0 The spring is due to a permeable water bearing bed
between relatively impermeable confining beds.
available chlorine - A measure of the total oxidizing power of chlorinated
liuie and hypochlorites.
bsckflov - (L) A flow condition, induced by a differential in pressure,
chat causes the flow of water or other liquid into the distribution
pipes of a potable water supply from any source or sources other
than its intended source. (2) The backing up of water through a
conduit or channel in the direction opposite to normal flow.
backflow preventer - a device for a water supply pipe to prevent the
hiackflou of vatez inco the water supply system from the connections
on the outlet end.
backsiphonage - A form of backflow caused by a negative or subatmospheric
pressure within a water system. See backflov/.
bacteria - A group of universally distributed, rigid8 essentially
unicellular microscopic organisms lacking chlorophyll. Bacteria
usually appear as spheroid, rod likes or curved entities, but
occasionally appear as sheets, chainss or branched filaments.
Bacteria are usually regarded as plants.
booster pump - A pump installed on a pipeline to raise the pressure of
the water or. the discharge side of the pump.
breakpoint chlorination - Addition of chlorine to water or wastewater
until the chlorine demand has been satisfied and further additions
result in a residual that is directly proportional to the amount
added beyond the breakpoint.
carbonate hardness - Hardness caused by the presence of carbonates and
bicarbonate?; of calcium and magnesium in water. Such hardness may
be removed to the limit solubility by boiling the water. When the
hardness is numerically greater than the sum cf che carbonate
alkalinity and the bicarbonate alkalinity„ that amount of hardness
which is equivaJent co the total alkalinity is called carbonate
hardness.
A-2
-------
casing shoe - A rigid annular fitting placed at the lower end of a metal
well casing, commonly with a cutting edge on the bottom.
chlorine contact chamber - A detention basin provided primarily to secure
the diffusion of chlorine through the liquid. Also called
chlorination chamber.
coagulation - In water and wastewater treatment, the destabilization and
initial aggregation of colloidal and finely divided suspended
matter by the addition of a floc-forming chemical or by biological
processes.
coliform-group bacteria - A group of bacteria predominantly inhabiting the
intestines of man or animal, but also occasionally found elsewhere.
combined available chlorine - The concentration of chlorine which is
combined with ammonia as chloramine or as other chloro derivitives,
yet is still available to oxidize organic matter.
corrosion control - (1) In water treatment, any method that keeps the
discharge of the metallic ions of a conduit from going into
solution, such as increasing the pH of the water, removing free
oxygen from the water, or controlling the carbonate balance of the
water. (2) The sequestration of metallic ions and the formation
of protective films on metal surfaces by chemical treatment.
cross connection - (1) A physical connection through which a supply of
potable water could be contaminated or polluted. (2) A connection
between a supervised potable water supply and an unsupervised
supply of unknown potability.
cement grout - A fluid mixture of cement and water, sometimes Including
additives such as sand, bentonite and hydrated lime, which can be
forced through a pipe, as in forming a seal in the annular space
of a well casing. Neat cement is a mixture of 1 bag of cement
(94 lbs.) to not more than 6 gallons of water and may include up to
5% additives to improve fluidity. Sand cement and concrete grouts
are also used in sealing a well casing.
diatomaceous-earth filter - A filter used in water treatment, in which a
built up layer of diatomaceous earth serves as the filtering medium.
disinfection - The art of killing the larger portion of micro-organisms in
or on a substance with the probability that all pathogenic bacteria
are killed by the agent used.
distribution reservoir - A reservoir connected with the distribution system
of a water supply, used primarily to accommodate fluctuations in
demand which occur over short periods (several hours to several days)
and also to provide local storage in case of emergency such as break
in a main supply line or failure of a pumping plant.
distribution system - (1) A system of conduits and their appurtenances by
which a water supply is distributed to consumers. The term applies
particularly to the network or pipelines in the streets in a domestic
water system and or to pipes and canals other than the main canal in
an irrigation system. (2) The network used for distributing elec-
trical power to consumers.
A-3
-------
drawdown - (1) The magnitude of the change in surface elevation of a body of
water as a result of the withdrawal of water therefrom. (2) The
magnitude of the lowering of the water surface in a well, and of the
water table or piezometric surface adjacent to the well, resulting from
the withdrawal of water from the well by pumping.
fire demand -The required fire flow and the duration for which it is needed,
usually expressed in gallons per minute for a certain number of hours.
Also used to denote the total quantity of water needed to deliver the
required fire flow for the specified number of hours.
free available residual chlorine - That portion of the total residual chlorine
remaining in water or wastewater at the end of a specified contact
period which will react chemically and biologically as hypochlorous acid
or hypochlorite ion.
groundwater - (1) Subsurface water occupying the saturation zone, from which
wells and springs are fed. In a strict sense the term applies only to
water below the water table. Also called phreatic water, plerotic water.
hardness - A characteristic of water, imparted by salts of calcium, magne-
sium and iron such as bicarbonates, carbonates, sulfates, chlorides
and nitrates, that causes curdling of soap and increased consumption
of soap, deposition of scale in boilers, damage in some industrial
processes, and sometimes objectionable taste.
ion exchange - (1) A chemical process involving reversible interchange of
Ions between a liquid and a solid but no radical change in structure
of the solid. (2) A chemical process in which ions from two different
molecules are exchanged.
pressure filter - A rapid sand filter of the closed type, having a vertical
or horizontal cylinder of iron, steel, wood or other material Inserted
in a pressure line.
red water - Rust colored water. Such color is usually due to the presence
of precipitated ferric iron salts or to dead organisms the life
processes of which depended on iron and manganese.
safe yield - The maximum dependable draft that can be made continuously
on a source of water supply {surface or groundwater) during a
period of years during which the probable driest period or period
of greatest deficiency in water supply is likely to occur. Dependa-
bility is relative and is a function of storage provided and drought
probability.
wastewater - The spent water of a community. From the standpoint of
source, it may be a combination of the liquid and water carried wastes
from residences, commercial building, industrial plants, and insti-
tutions, together with any groundwater, surface water, and storm water
that may be present. In recent years, the word wastewater has taken
precedence over the word sewage.
water borne disease - A disease caused by organisms or toxic substances
carried by water. The most common water-borne diseases are typhoid
fever, Asiatic cholera, dysentery, and other intestinal disturbances.
A-4
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water conditioning - Treatments, exclusive of disinfection, intended to
produce a water free of taste, odor, and other undesirable qualities.
water consumpcion - The quantity ox- quantity per capita, of water supplied in
a municipality or district for a variety of uses or purposes during
a given period. It is usually taken to mean all uses included within
the tana municipal use of water and quantity wasted, lost or otherwise
unaccounted for.
water hariuner - Tiia phenomenon of oscillations in the pressure of water about
its normal pressure in a closed conduit, flowing full, that results from
a too-rapid acceleration or retardation of flow. Momentary pressures
greatly in excess of the normal static pressure may be produced in a
closed conduit by this phenomenon.
water quality - The chemical, physical, and biological characteristics of
water with respect to its suitability for a particular purpose. The
sains water may be of good quality for one purpose or use, and bad for
another, depending on its characteristics and the requirements for the
particular use.
water treatment - The filtration or conditioning of water to render it
acceptable for a specific use-
v;ell cone of influence - The depression, roughly conical in shape, pro-
duced in a v/ater table or other piezometric surface by the extraction
of water from a wel] at a given rate. The volume of the cone will vary
with the rate and duration of withdrawal of water. Also called cone of
depression.
uell log - A chronological record of the soil and rock formations encountered
in the operation of sinking a well* with either their thickness or the
elevation of the top and bottom of each formation given. It also usually
includes statements about the lithologic composition and water bearing
characteristics of each formation# static and pumping water levels,
and well yield,.
A-5
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APPENDIX B
STATE WATER SUPPLY AGENCIES
Alabama
Division of Public Water Supplies
Environmental Health Administration
State Office Building
Montgomery, AL 36130
Alaska
Division of Air & Water Quality Control
Dept. of Environmental Conservation
Pouch 0
Juneau, AK 99801
Arkansas
Bureau of Consumer Protection Services
State Department of Health
4815 W. Markham Street
Little Rock, AR 72201
Arizona
Bureau of Water Quality Control
1740 West Adams Street
Phoenix, AZ 85007
California
State Department of Health
2151 Berkeley Way
Berkeley, CA 94704
Colorado
Engineering & Sanitation
Department of Health
4210 E. 11th Avenue
Denber, CO 80220
Connecticut
Water Supply Division
CT Department of Health
Elm Street
Hartford, CT 06115
Delaware
Bureau of Environmental Health
Dept. of Health & Social Services
Jesses. Cooper Building
Capitol Square
Dover, DE 19901
District of Columbia
Water Resources Administration
415 12th Street N.W.
Washington, D.C. 20001
Florida
Bureau of Drinking Water & Special
Programs
FL Dept. of Environmental Reg.
2562 Executive Center Circle, E.
Tallahassee, FL 32301
B-
Georgia
Water Protection Branch
GA Dept. of Natural Resources
270 Washington Street, S.W.
Room 822
Atlanta, GA 30334
Hawaii
HI State Department of Health
Environmental Protection Div.
Pollution Technical Review Bureau
P.O. Box 3378
Honolulu, HI 96801
Idaho
Department of Health & Welfare
Statehouse
Boise, ID 83720
Illinois
Division of Public Water Supply
IL Environmental Protection Agency
4500 South 6th Street
Springfield, IL 62706
Indiana
Division of Sanitary Engineering
State Board of Health
1330 West Michigan Street
Indianapolis, IN 46206
Iowa
Water Quality Management Division
Department of Environmental Quality
P.O. Box 3326
Des Moines, IA 50316
Kansas
Water Supply Section
Division of Environment
Dept. of Health & Environment
Topeka, KS 66620
Kentucky
Division of Sanitary Engineering
KY Dept. for Natural Resources &
Environmental Protection
Century Plaza-U.S. 127 South
Frankfort, KY 40601
Louisiana
Bureau of Environmental Health
LA Health & Human Resources Adm.
Division of Health
P.O. Box 60630
New Orleans, LA 70160
-------
Maine
Division of Environmental Engineering
HE Department of Human Services
State House
Augusta, ME 04330
Maryland
Water Supply
Division of Water & Sewerage
State Dept. of Health & Mental Hygiene
201 W. Preston Street
Baltimore, MD 21201
Massachusetts
Division of Water Supply
MA Dept. of Environmental Quality Eng.
600 Washnngton Street
Boston, MA 02111
Michigan
Department of Public Health
Division of Water Supply
3500 North Logan Street
Box 30035
Lansing, MI 48919
Minnesota
Water Supply & General Engineering
MM Department of Health
715 Delaware St., S.E.
Minneapolis, MN 55440
Mississippi
Division of Water Supply
State Board of Health
P.O. Box 1700
Jackson, MS 39205
Missouri
Water Supply Program
Division of Environmental Quality
P.O. Box 1368
Jefferson City, M0 65101
Montana
Water Quality Bureau
Dept. of Health & Env. Sciences
Cogswell Building
Helena, MT 59601
Nebraska
Division of Environmental Eng.
Department of Health
Lincoln Building
10th and 0 Streets
Lincoln, NB 68509
Nevada
Department of Human Resources
201 South Fall Street
Carson City, NV 89710
Hew Hampshire
NH Water Supply & Pollution Control
Commission
105 Loudon Road
Concord, NH 03301
New Jersey
Bureau of Potable Water
Dept. of Environmental Protection
P.O. Box 2809
Trenton, NJ 08625
New Mexico
Water Supply Section
Environmental Improvement Agency
P.O. Box 2348
Santa Fe, NM 87501
New York
Bureau of Public Water Supply
NY Department of Health
Empire State Plaza
Albany, NY 12237
North Carolina
Sanitary Engineering Section
Division of Health Services
Department of Human Resources
Bath Bldg., P.O. Box 2091
Raleigh, NC 27602
North Dakota
Division of Water Supply & Pollution
Control
Department of Health
State Capitol
Bismarck, ND 58501
Ohio
Office of Public Water Supply
OH Environmental Protection Agency
P.O. Box 1049
Columbus, OH 43216
Oklahoma
Water Quality Service
Department of Health
N.E. 10th & Stonewall
Oklahoma City, OK 73117
Oregon
Office of Sanitation Services
Dept. of Human Resources
1400 S.W. Fifth Avenue
Portland, OR 97201
Pennsylvania
Division of Water Supply & Sewage
Pennsylvania Dept. of liriv. Resources
P.O. Box 2063
Harrisburg, PA 17120
B-2
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Rhode Island
RI Department of Health
Health Bldg., Room 209
75 Davis Street
Providence, RI 02908
South Carolina
Division of Water Supply
SC Dept. of Health & Env. Resources
2600 Bull Street
Columbia, SC 29201
South Dakota
Water Hygiene Program
Dept. of Environmental Protection
Joe Foss Building
Pierre, SD 57501
Tennessee
Division of Environmental Sanitation
TN Dept. of Public Health
320 Capitol Hill Building
Nashville, TN 37219
Texas
Environmental & Consumer Health
Protection
TX Dept. of Health Resources
1100 West 49th Street
Austin, TX 78756
Utah
Bureau of Water Quality
Environmental Health Branch
44 Medical Drive
Salt Lake City, UT 84113
Vermont
Division of Environmental Health
VT Department of Health
60 Main Street
Burlington, VT 05401
Virginia
Bureau of Sanitary Engineering
State Department of Health
James Madison Building
109 Governor Street
Richmond, VA 23219
Washington
Water Supply & Waste Unit
Dept. of Social & Health Services
P.O. Box 1788
Olympia, WA 98504
West Virginia
Drinking Water Program
Environmental Health Services
Stare Department of Health
1800 E. Washington Street
Charleston, WV 25305
Wisconsin
Public Water Supply Section
Dept. of Natural Resources
P.O. Box 450
Madison, WI 53701
Wyoming
Water Quality Division
Dept. of Environmental Quality
Hathaway Bldg.
Cheyenne, WY 82002
Samoa
Department of Public Works
Government of American Samoa
Pago Pago, American Samoa 96920
Guam
Environmental Protection Agency
Government of Guam
P.O. Box 2999
Agana, Guam 96910
Mariana Islands
Chief of Environmental Health
Dept. of Health Services
Trust Territory of the Pacific Islands
Saipan, Mariana Islands 96950
Puerto Rico
Water Supply Program
PR Health Department
P.O. Box 9342
Hayto Rey, Puerto Rico 00927
Virgin Islands
Department of Conservation
Division of Natural Resource Mgmt.
Building 15-F
Watergut Homes
Christiansted, St. Croix
U.S. Virgin Islands 00820
B-3
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U.S.ENVIRONMENTAL PROTECTION AGENCY REGIONAL OFFICES
EPA REGIONAL OFFICES
EPA Region 1
Room 2303
JFK Federal Building
Boston, MA 02203
EPA, Region 2
Room 1005
26 Federal Plaza
New York, NY 10007
EPA Region 3
Curtis Building
6th and Walnut Streets
Philadelphia, PA 19106
EPA Region 4
345 Courtland St., NE
Atlanta, GA 30308
EPA Region 5
230 South Dearborn Street
Chicago, IL 60604
EPA Region 6
1201 Elm St
Dallas, TX 75270
EPA Region 7
1735 Baltimore Street
Kansas City, MO 64108
EPA Region 8
Suite 900
1860 Lincoln Street
Denver, CO 80203
EPA Region 9
215 Freemont Street
San Francisco, CA 94111
EPA Region 10
1200 Sixth Avenue
Seattle, WA 98101
3-^
STATES COVERED
Connecticut, Maine,
Massachusetts, New
Hampshire, Rhode Island
Vermont
New Jersey, New York, Puerto
Rico, Virgin Islands
Delaware, Maryland,
Pennsylvania, Virginia, West
Virginia, District of Columbia
Alabama, Georgia, Florida,
Mississippi, North Carolina,
South Carolina, Tennessee,
Kentucky
Illinois, Indiana, Ohio
Michigan, Wisconsin,
Minnesota
Arkansas, Louisiana
Oklahoma, Texas, New Mexico
Iowa, Kansas, Missouri
Nebraska
Colorado, Utah, Wyoming
Montana, North Dakota, South
Dakota
Arizona, California, Nevada,
Hawaii
Alaska, Idaho, Oregon
Washington
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APPENDIX C
REFERENCES AND SELECTED BIBLIOGRAPHY
GENERAL
!• Water Facts and Figures for Planners and Managers.
Geological Survey, Circular 601-0, U.S. Department of
the Interior.
2. Manual of Individual "fater S':""ply Systems. U.S.
Environmental Protection Agency (1973)
3. Water Systems Handbook. Water Systems Council, 221 N. LaSalle
St., Chicago, 111., 60601. A rather complete handbook on
well systems.
4-. National Standard Plumbing Code. National Association
of Plumbing, Heating, Cooling Contractors (1971).
5. Fire Protection Handbook. National Fire Protection
Association, Thirteenth Edition (1969)
6. Standards for the Installation of Standpipe and Hose
Systems. NFPA No. 14, 197^- National Fire Portection
Association.
7. Standards for the Installation of Sprinkler Systems,
NFPA No. 13. 1974. National Fire Protection Association.
8. Guide to Water Systems Construction - Recommended
Industry Practices, 2nd Printing, Water Systems Council,
221 LaSalle St., Chicago, Illinois 60601.
Booklet written in layman's terms describing location
and construction, and friction losses in supply lines
and basic pump design.
9* Minimum Design Standards for Community Water Supply
Systems. U.S. Dept of Housing and Urban Development
Handbook, FHA 4517*1. May, 1968.
10. Practical Engineering Information. Red Jacket Manufacturing
Co., P.O. 3ox 3888, Davenport, Iowa 52808.
Includes information about water systems, selection of
pumping equipment, water requirements and storage tanks.
Many charts of engineering information
¦H* Rural Water Systems - Planning and Engineering Guide.
Michael D. Campbell and Jay H. Lehr, Commission on Rural
Water, Washington, D.C. (1973).
A rather complete guide, including cost analysis and
comparison.
C-l
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12. Cross-Connection Control Manual. Water Supply Division
U.S. Environmental Protection Agency, U.S. Gov. Printing
Office, Washington, D.C. 20402
13. Cameron Hydraulic Data, Compressed Air Magazine Co., Book
and Periodical Division, 942 Memorial Parkway, Phillipsburg,
N.J., 08865.
WATER WELLS*
14. AWWA Standard for Deep Wells, (AWWA-A100-66) American
Water Works Association, 6666 W. Quincy Ave., Denver, Colorado,80235.
15. Ground Water. National Water Well Association,
88 E. Broad St., Columbus, 0. 43215.
A technical journal published by NWWA's Technical Division
16. Ground Water Hydrology for Water Well Drilling
Contractors, Jon Rau, National Water Well Association,
88 E. Broad St., Columbus, 0. 43215, (19?0)
17. Manual of Water Well Construction Practices, EPA-
570/9-75-001, U.S. Govt. Printing Office, Washington, D.C.,
20402
18. Ground Water - AWWA Manual No. M21. American Water Works
Association, 6666 W. Quincy Ave., Denver, Colorado,80235.
19. Water Well Handbook. Keith Anderson, Missouri Water Well
Drillers Association, Box 250, Rolla, M0., 65401
20. Ground Water and Wells,Univers^fOil Products, Johnson Division,
Saint Paul, Minnesota, 55100
PUMP SYSTEMS*
21. Application Manual for Large Submersible Pumps. Red
Jacket Manufacturing Co., P.O. Box 3888, Davenport, Iowa
52808.
Information on the proper application of large submersible
water pumps v-ith a discussion of the effects of well
conditions, abrasives, corrosives and temperatures.
22. Compact Service Manual, Goulds Pumps, Inc., Advertising
Dept. Seneca Falls, N.Y. 13148.
Summariz.es installation, operation and maintenance
procedures covering nearly all jet, centrifugal and sub-
mersible pumps made by Goulds.
* Consult local pump suppliers for additional bulletins.
C-2
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23.
.
25.
Installation of Submersible Pumps, Red Jacket Mfg. Co.,
P.O. Box 3888, Davenport, Iowa 52808.
Describes a "Drain-back" System to eliminate aeration
of iron bearing water.
Pump Fundamentals Workbook. Goulds Pumps, Inc.
Advertising Dept., Seneca Falls, New York, NY 13148.
A basic introduction and summary of pumps.
Vater Systems Pump Fundamentals. Goulds Pumps, Inc.
Advertising Dept., Seneca Falls, New York, NY 13148.
A basic introduction and summary of water system
operations.
VATER QUALITY
26. Standard Methods for the Examination of Water and Waste
Water. American Public Health Association,Inc.
Approved sampling, testing and interpretation information.
27. National Interim Primary Drinking Water Regulations.
U.S. Environmental Protection Agency, Federal Register,
December 24, 1975.
WATER TREATMENT
28 A Guide to Trouble-Free Water Conditioning Systems.
Red Jacket Manufacturing Co., P.O. Box 38888, Davenport,
Iowa 52808.
Lists fourteen primary water problems and explains how
to specify the right equipment to correct them.
29. Water Quality and Treatment, Prepared by American Water
Works Association,4666 W. Quincy Ave., Denver, Colorado, 80235.
30. Basic Water Treatment Operator's Manual. American Water
toOrkS Association (AWWA NO. MIO) , 6666 W. Quincy Ave. , Denver,
Colorado, 80235.
31. Disposal of Wastes from Water Treatment Plants. AWWA
Research Foundation Report, Journal AWWA, October,
November and December 1969.
32. State Of the Art Of Small Water Treatment Systems,
U.S. EPA, Government Printing Office, Washington, D.C.
20402.
SAFETY PRACTICES
33. Safety Practices for Water Utilities (M3), American Water Works
Association, 6666 W. Quincy Ave., Denver, Colorado, 80235.
C-3
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APPENDIX D
TECHNICAL REPORT DATA
/Please reed instructions on the reverse before completing)
1 REPORT NO
NONE
3 RECIPIENT'S ACCESSION NO
4 TITLE AND SUBTITLE
MANUAL SMALL WATER SYSTEMS SERVING THE PUBLIC
Correlated with National Drinking Water
Regulations
5 REPORT DATE
July 1978 .
6 PERFORMING ORGANIZATION COOS
7.AUTUORIS) _ _ _
Conference.of State Sanitary Engineers
> Sanitary Engm
8 PERFORMING ORGANIZATION REPORT NO
echnica
mih
¦ngmeer,
B PERFORMING ORGANIZATION NAME AND ADDRESS
Conference of State Sanitary Engineers,
Meredith H. Thompson, P.E. Executive Secretar
1 Deerfield Drive, Troy, NY 12180
10 PROGRAM ELEMENT NO
;1 WNYfUCT/GAANV kid
T900624010
13 SPONSORING AQENCV NAME AND ADDRESS
Office of Drinking Water
U.S. EPA
Washington, D.C. 20460
TYP.E Of. REPORT AftfD PERIOD COVERED ,
Dmall water Systems ManuaL
14 SPONSORING AGENCY CODE
16 SUPPLEMENTARY NOTES
16 ABSTRACT
The Manual is prepared as a guide for the planning, design, develop-
ment, maintenance, operation and evaluation of small water systems
serving the public, particularly the non-community system, but also
including small community type systems of 50 services or less. It is
coorelated with the National Drinking Water Regulations. The Manual
is designed to serve the particular needs of:
- Owners and operators of small water systems serving the public
- The design engineer
- State and local enforcing agencies as a tool to assist in inspec-
tion and evaluation responsibilities
KEY WOROS AND DOCUMENT ANALYSIS
DESCRIPTORS
b IDENTIFIERS/OPEN ENDEO TERMS C COSATl Field/Group
\B DISTRIBUTION STATEMENT
Interim printing. Available in
limited quantities at CSSE and EPA,
above.
10 SECURITY CLASS {ThURtport)
21 NO OF PAGES
272
20 SECURITY CLASS {This pagef
EPA Form 2220 1 (*-71)
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