United States
Environmental Protection
Water Quality in Small Community
Distribution Systems
A Reference Guide for Operators


                                                      March 2008
              Water Quality in
 Small Community Distribution Systems

      A Reference Guide for Operators
    U.S. Environmental Protection Agency

     Office of Research and Development
National Risk Management Research Laboratory
  Water Supply and Water Resources Division
               Cincinnati, Ohio
                                          Printed with vegetable-based ink on
                                          paper that contains a minimum of
                                          50% post-consumer fiber content
                                          processed chlorine free

The document was prepared by Shaw Environmental, Inc. (Shaw) under EPA Contract No. EP-C-05-056,
Work Assignment No. 0-10 and 1-10, with Pegasus Technical Services, Inc. Mr. Radha Krishnan, P.E.,
was the Shaw Program Manager for this contract and Mr. Srinivas Panguluri, PE. was the Shaw Project
Leader for this Work Assignment.  Dr. Walter Grayman, P.E.,  and Dr. Robert Clark, P.E., D.E.E. were
consultants to Shaw on this Work Assignment.  Ms. Lucille M. Garner served as EPA Work Assignment
Manager and Mr. Craig L. Patterson, P.E., served as the Alternate EPA Work Assignment Manager. Mr.
Roy C. Haught served as EPA Technical Advisor.

Any opinions expressed in this document/reference guide for utilities are those of the author(s) and do
not, necessarily, reflect the official positions and policies of the U.S. Environmental Protection Agency
(EPA). Any mention of products or trade names does not constitute recommendation for use by EPA.
This document has been reviewed in accordance with ERA'S peer and administrative review policies and
approved for publication.


The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the Nation's
land, air, and water resources. Under a mandate of national environmental laws, the Agency strives to
formulate and implement actions leading to a compatible balance between human activities and the ability
of natural systems to support and nurture life. To meet this mandate, ERA'S research program is providing
data and technical support for solving environmental problems today and building a science knowledge
base necessary to manage our ecological resources wisely, understand how pollutants affect our health,
and prevent or reduce environmental risks in the future.

The National Risk Management Research Laboratory (NRMRL) is the Agency's center for  investiga-
tion of technological and management approaches for preventing and reducing risks from pollution that
threaten human health and the environment. The focus of the Laboratory's research program is on meth-
ods and their cost-effectiveness for prevention and control of pollution to air, land, water, and subsurface
resources; protection of water quality in public water systems; remediation of contaminated sites, sedi-
ments and ground water; prevention and control of indoor air pollution; and restoration of ecosystems.
NRMRL collaborates with both public and private sector partners to  foster technologies that reduce
the cost of compliance and to anticipate emerging problems. NRMRL's research provides solutions to
environmental  problems by: developing and promoting technologies that protect and improve the envi-
ronment; advancing scientific and engineering  information to support  regulatory and policy decisions;
and providing the technical support and information transfer to ensure implementation of environmental
regulations and strategies at the national, state, and community levels.

This publication has been produced as part of the Laboratory's strategic long-term research plan. It is
published and made available by EPA's Office of Research and Development to assist the user commu-
nity and to link researchers with their clients.

                                               Sally Gutierrez, Director
                                               National Risk Management Research Laboratory


      The U.S.  Environmental Protection Agency (EPA) has developed this reference guide to assist the
      operators and managers of small- and medium-sized public water systems. This compilation provides a
      comprehensive picture of the impact of the water distribution system network on distributed water quality.
      This reference guide provides information on the following topics:
                    •  Water supply and distribution process overview
                    •  Distribution system infrastructure
                    •  Drinking water regulations
                    •  Distribution system water quality issues
                    •  Distribution system monitoring, control and security
                    •  Operational, financial and management strategies to address
                      distribution system water quality
      In addition, to make this document appeal to a diverse group of small system operators and managers,
      graphical  elements  such as  pictures,  tables, blue sidebars,  and cartoon  illustrations have  been used
      throughout the document. Although every water distribution system is different (in terms of specific
      layout and operations),  all water distribution systems generally have the same components and operate
      under similar principles and operational strategies. To illustrate solutions to some of the common  issues
      faced by the small community distribution system operators, an example of a small water distribution
      network (SmallWater, USA)  has been included in this document.  At the end of many chapters, one
      or more SmallWater problem scenario(s) are presented along with some guidance on  resolving these
      Other related EPA reference guides in this area include the following:
          •  Small Drinking Water Systems: State of the Industry and Treatment Technologies to Meet
            the Safe Drinking Water Act Requirements. EPA Publication Number: 600-R-07-110
          •  Water Distribution  System Analysis: Field Studies, Modeling and Management - A
            Reference Guide for Utilities.  EPA Publication  Number: 600-R-06-028
          •  Small Drinking Water Systems Handbook: Guide to "Packaged" Filtration and Disinfection
            Technologies with Remote Monitoring and Control Tools. EPA Publication Number: 600-

                                    Table of Contents

1.0  Introduction	1-1
    1.1  Purpose and Scope of the Document	1-1
    1.2  Graphical Elements and Cartoon Illustrations	1-1
    1.3  SmallWater, USA- Problem Scenarios	1-2
    1.4  Content Development and Description	1-2
2.0  The Supply, Distribution, and Quality of Water: An Overview	2-1
    2.1  Protecting Source Water Quality	2-1
    2.2  Water Treatment, Supply and Distribution	2-2
    2.3  History of Water Supply and Treatment in the United States	2-3
    2.4  History of Water Quality Regulations and Standards in the United States	2-3
    2.5  Public Water System	2-4
       2.5.1  Type and Size of Systems	2-4
       2.5.2  Type of Source Water Used	2-5
       2.5.3  Type of Ownership	2-6
    2.6  Common Problems Faced by Small and Medium Utilities	2-6
       2.6.1  Water Quality Problems	2-6
       2.6.2  Operational Problems	2-7
       2.6.3  Regulatory/Compliance Problems	2-7
       2.6.4  Institutional  Problems	2-7
    2.7  SmallWater, USA Scenario	2-7
3.0  Distribution System Infrastructure	3-1
    3.1  The Impact of Distribution  System on Water Quality	3-1
    3.2  Distribution System Pipes  	3-2
       3.2.1  Pipe Connectivity, Placement and Configuration	3-2
       3.2.2  Pipe Material	3-3
       3.2.3  Common Problems, Troubleshooting and Pipe Repair	3-4
    3.3  Distribution System Pumps	3-5
       3.3.1  Common Problems, Troubleshooting and Maintaining Pumps	3-6
    3.4  Distribution System Storage Facilities	3-6
       3.4.1  Types of Storage Facilities	3-6
       3.4.2  Common Problems, Troubleshooting and Maintaining Tanks	3-7
    3.5  Distribution System Valves	3-8
       3.5.1  Gate Valves	3-8
       3.5.2  Butterfly Valves	3-8
       3.5.3  Check Valves	3-9
       3.5.4  Other Valves	3-9
       3.5.5  Common Problems, Troubleshooting and Maintaining Valves	3-9
    3.6  Distribution System Hydrants	3-10
       3.6.1  Common Problems, Troubleshooting and Maintaining Hydrants	3-10
    3.7  Water Meters and Service Lines	3-11
       3.7.1  Water Meters	3-11
       3.7.2  Service Lines	3-11
       3.7.3  Common Problems, Troubleshooting and Repairs	3-11
    3.8  Distribution System Asset  Management	3-12
    3.9  Distribution System Modeling	3-13
    3.10 SmallWater, USA-Asset  Management Problem Scenario	3-16
4.0  Drinking Water Regulations	4-1
    4.1  Highlights of 1974 SDWA and its Amendments	4-3
       4.1.1  1986 Amendments to SDWA	4-3
       4.1.2  1996 Amendments to SDWA	4-3
       4.1.3  Variances and Exemptions	4-3
    4.2  Regulations to Control Microbial Contaminants	4-4

         4.3  Regulations to Control Chemical Contaminants	4-5
         4.4  Public Notification and Consumer Confidence Rules	4-5
         4.5  SmallWater, USA - Regulatory Scenario Problems	4-9
      5.0  Distribution System Water Quality Issues	5-1
         5.1  Taste, Odor, and Color	5-1
             5.1.1  Taste and Odor Problems	5-1
             5.1.2  Color Problems	5-2
         5.2  Biofilm 	5-3
             5.2.1  Factors Aiding Biofilm Growth	5-4
             5.2.2  Operational Factors Inhibiting the Growth of Biofilm	5-4
         5.3  Disinfection and Disinfection Byproducts	5-5
         5.4  Nitrification	5-6
         5.5  pH Stability and Scale Formation	5-6
         5.6  Contamination Events	5-7
             5.6.1  Cross-connections and Backflow	5-7
             5.6.2  Permeation and Leaching 	5-8
             5.6.3  Intrusion and Infiltration 	5-8
             5.6.4  Storage Facility Contamination  	5-8
         5.7  SmallWater, USA-Water Quality Problem Scenarios	5-9
      6.0  Distribution System Monitoring, Control,  and Security	6-1
         6.1  Monitoring a Distribution System	6-1
         6.2  Distribution System Hydraulic Monitoring	6-2
             6.2.1  Flow and Velocity Monitoring	6-2
             6.2.2  Pressure Monitoring	6-4
         6.3  Distribution System Water Quality Monitoring	6-5
         6.4  Controlling a Distribution System	6-6
             6.4.1  SCADA Instrumentation and Hardware	6-6
             6.4.2  SCADA Operator Interface	6-6
             6.4.3  Communication Media	6-7
             6.4.4  Selection of SCADA Systems	6-7
         6.5  Securing a Distribution System	6-8
             6.5.1  Distribution System Vulnerabilities	6-8
             6.5.2  Operational and Emergency Response Mechanisms	6-9
         6.6  SmallWater, USA - Monitoring, Control and Security Problem Scenarios	6-10
      7.0  Strategies to Address Distribution System Water Quality Issues	7-1
         7.1  Operational Strategies	7-1
             7.1.1  Reducing Water Age in the Distribution System	7-1
             7.1.2  Adapting Operations to Meet System-Specific Water Demands	7-2
             7.1.3  Changing Disinfectants	7-2
             7.1.4  Implementing Corrosion Control	7-3
             7.1.5  Preventing Sedimentation and Scale Formation	7-4
             7.1.6  Implementing a Flushing  Program	7-4
             7.1.7  Infrastructure Replacement and/or Treatment Upgrades	7-5
         7.2  Financial Strategies	7-5
             7.2.1  Drinking Water State Revolving  Fund	7-6
             7.2.2  Community Development Block Grants	7-7
             7.2.3  Rural Utilities System	7-7
             7.2.4  Economic Development Administration	7-7
             7.2.5  Other Entities and Private Foundations	7-8
         7.3  Management Strategies	7-8
             7.3.1  Small Systems Working Together	7-8
             7.3.2  Change in Ownership and/or Management	7-9
         7.4  SmallWater USA - Cell Tower  Installation	7-9
      8.0  Bibliography	8-1

                                      List of Tables

Table 3.1    Infrastructure Components	3-1
Table 3.2    Potential Negative Impacts to Water Quality Based on Pipe Material and Changes in
            Water Quality	3-3
Table 3.3    Common Problems that Lead to Pipe  Failure for Various Pipe Materials	3-5
Table 3.4    Listing of Low-cost CADD and CIS Application Software	3-14
Table 3.5    Available Hydraulic-Water Quality Network Modeling Software Packages	3-16
Table 3.6    Hydrant Inventory Information	3-17
Table 3.7    Event Table	3-17
Table 4.1    Summary of Regulations Designed to Control Microbial Contamination	4-6
Table 4.2    Summary of Regulations Designed to Control Chemical Contamination	4-7
Table 6.1    Flow Meters	6-3
Table 6.2    Cost of SCADA Implementation at Coalwood, WV.	6-7

                                      List of Figures

Figure 1.1   "Rogue's Gallery" of fictional characters used in this reference guide	1-1
Figure 2.1   The Hydrologic Cycle or"Water Cycle"	2-1
Figure 2.2   Multiple Risks to Public Health	2-2
Figure 2.3   A Typical Water Supply System Using Surface Water as Source	2-3
Figure 2.4   A Schematic Representation of a Water Distribution System	2-3
Figure 2.5   Classification of PWSs in the U.S	2-5
Figure 2.6   Distribution of PWSs by Size	2-5
Figure 2.7   Distribution of Small- and Medium-Sized PWSs by Source of Water Used	2-6
Figure 2.8   Distribution of Small- and Medium-Sized PWSs by Ownership	2-6
Figure 2.9   SmallWater, USA - Schematic Layout	2-8
Figure 3.1   A Branched Distribution System	3-2
Figure 3.2   A Grid/Looped Distribution System	3-2
Figure 3.3   NSF-Approved PVC Pipe for Potable Water Use	3-3
Figure 3.4   Pipe Wall Interactions that Affect Water Quality	3-3
Figure 3.5   Storage Tank Volume  Design Requirements	3-7
Figure 3.6   Gate Valve (side view)	3-8
Figure 3.7   Butterfly Valve (top view)	3-9
Figure 3.8   Swing Check Valve (side view)	3-9
Figure 3.9   Dry Barrel Hydrant	3-10
Figure 3.10  Arenas Valley Pipe Inventory and Main Break Map	3-12
Figure 3.11  Screen-shot Showing the Results of an Analysis for the SmallWater Distribution
            System	3-14
Figure 3.12  EPS Plots of Tank Water Levels and Flow in a Water Main Over a 2-Day Period	3-15
Figure 3.13  Components in the SmallWater Distribution System	3-17
Figure 3.14  Hydrant locations in part of SmallWater	3-17
Figure 3.15  Sample Asset Management Database Design or Schema	3-17
Figure 4.1   The Evolution of Federal Drinking Water Standards	4-2
Figure 4.2   Disease-Causing Microorganisms - E. coli, Giardia and Cryptosporidium (not to scale) 4-5
Figure 4.3   Sample Public Notice	4-8
Figure 5.1   Drinking Water Taste and Odor Wheel	5-3
Figure 5.2   Biofilm Growth Inside the Pipe	5-4
Figure 5.3   Water Age Within SmallWater, USA	5-10
Figure 6.1   Manual Water Quality Sampling and Field Testing	6-2
Figure 6.2   Automated Water Quality Monitoring	6-2
Figure 6.3   Hydrant Flow Gages	6-4
Figure 6.4   Digital and analog pressure meter attached to fire hydrant	6-5
Figure 6.5   Readout meters for flow, water level and pressure from a SCADA system	6-5
Figure 7.1   Crowded Cell Tower Installation	7-11
Figure 7.2   A Well-Designed and  Constructed Cell Tower Installation	7-11

                                Acronyms and Abbreviations
     AM        Asset Management
     AMR       Automatic Meter Reading
     ANSI       American National Standards
     AOC       Assimilable Organic Carbon
     ARC       Appalachian Regional Commission
     ASTM      American Society for Testing
     AWWA     American Water Works Association
     AwwaRF   American Water Works Association
                Research Foundation
     BAT       Best Available Treatment
     BDOC      Biodegradable Organic Carbon
     CaCOS     Calcium Carbonate
     CADD      Computer-Aided Design and Drafting
     CCR       Consumer Confidence Report
     CDBG      Community Development Block
     CWA       Clean Water Act
     CWS       Community Water System
     DBP       Disinfection Byproduct
     D/DBPR    Disinfectants/Disinfection Byproducts
     DWSRF    Drinking Water State Revolving Fund
     EDA       Economic Development
     EPS       Extended Period Simulation
     ERP       Emergency Response Plan
     EPA       United States Environmental
                Protection Agency
     FBRR      Filter Backwash Recycling Rule
     fps        Feet per Second
     CIS       Geographic Information System
     gpm       Gallons Per Minute
     GPS       Global Positioning  System
     GWR      Ground Water Rule
     GWUDI     Ground Water Under Direct Influence
                (of Surface Water)
     HAA       Haloacetic Acids
     HOPE      High-Density Polyethylene
     HPC       Heterotrophic Plate Count
     IESWTR   Interim Enhanced Surface Water
                Treatment Rule
     IDSE       Initial Distribution System Evaluation
     IMS       Indian Health Service
I/O        Input/Output
IOC       Inorganic Compounds
IRS       Internal Revenue Service
LCR      Lead and Copper Rule
LOS      Level of Service
LRAA     Locational Running Annual Average
LSI        Langelier Saturation Index
LT1ESWTR Long-term 1 Enhanced Surface
          Water Treatment Rule
LT2ESWTR Long-term 2 Enhanced Surface
          Water Treatment Rule
MCL      Maximum Contaminant Level
MCLG     Maximum Contaminant Level Goal
MCPSD   McDowell County Public Service
ug/L      Micrograms per Liter
mg/L      Milligrams per Liter
NDWC     National Drinking Water
NIPDWR   National Interim Primary Drinking
          Water Regulations
NKWD     Northern Kentucky Water District
NMEFC   New Mexico Environmental Finance
NPDES   National Pollutant Discharge
          Elimination  System
NRWA     National Rural Water Association
NSDWR   National Secondary Drinking Water
NTNCWS  Non-Transient Non-Community Water
O&M      Operation and Maintenance
OSHA     Occupational Safety and Health
PD        Positive Displacement
POE      Point of Entry
POU      Point of Use
PRV      Pressure Reducing Valve
PVC      Polyvinyl Chloride
PWS      Public Water System
RAA      Running Annual Average
REM      Roentgen Equivalent Man
RTU      Remote Terminal Unit
RUS      Rural Utilities System

SBREFA   Small Business Regulatory
          Enforcement Act
SCADA    Supervisory Control and Data
SCWIE    Small Community Water
          Infrastructure Exchange
SDWA     Safe Drinking Water Act
SMF      Standardized Monitoring Framework
SOC      Synthetic Organic Compounds
SSCT     Small System Compliance
STEP     Simple Tools for Effective
SWTR     Surface Water Treatment Rule
TCR      Total Coliform Rule
THM      Trihalomethanes
TMDL     Total Maximum Daily Load
TNCWS   Transient Non-Community Water
TOC      Total Organic Carbon
TT        Treatment Technique
UF        Ultrafiltration
UL        Underwriters Laboratory
USDA     U.S. Department of Agriculture
U.S.       United States
USA      United States of America
VA        Vulnerability Assessment
VOC      Volatile Organic Compounds
WV       West Virginia


      The principal authors of this document, titled "Water Quality in Small Community Distribution Systems
      - A Reference Guide for Operators," were: Mr. Srinivas Panguluri, RE., Dr. Walter M. Grayman, RE., Dr.
      Robert M. Clark, RE., D.E.E., Mr. E. Radha Krishnan, RE., Ms. Lucille M. Garner, Mr. Craig L. Patterson,
      RE., and Mr. Roy C. Haught.

      The authors wish to acknowledge the contributions of the following individuals and organizations towards
      the development of this document:

      EPA technical reviews of the document were performed by:
         Mr. Thomas Grubbs, RE., Environmental Engineer, EPA Office of Ground Water and Drinking
            Water (OGWDW)
         Mr. Michael Finn, RE., Environmental Engineer, EPA OGWDW, Standards and Risk Reduction
         Mr. Steve Clark,  Environmental Health Scientist,  EPA OGWDW, Drinking Water Protection Branch

      EPA Office of Research and Development (ORD) Quality Assurance, editorial and graphical reviews
      were performed by:
         Mr. Stephen M. Harmon, Quality Assurance Manager- Quality Assurance Review
         Dr. Jean Dye - Editorial Review
         Mr. Patrick Burke - Publishing Review
         Mr. Steve Wilson - Review of Illustrations

      Ohio EPA Drinking Water Division staff for coordination of site visits to small water distribution systems
      and providing state perspective on key issues:
         Mr. Dan Cloyd, Environmental Specialist 3
         Mr. Jeff G. Davidson, Environmental Manager
         Mr. Daniel J. Stine, Environmental Supervisor

      External technical reviews of the document were performed by:
         Mr. Jerry C. Biberstine, RE., of the National Rural Water Association
         Mr. Gary Burlingame of the Philadelphia Water Department
         Mr. Gary Lynch of the Park Water Company
         Mr. Lee Larue with the National Park Service at Mt. Rainer, Washington

      Assistance during the conduct of site visits to small water distribution systems:
         Mr. Jeremy Fite and Mr. Jason Barger at Williamsburg, Ohio
         Mr. Fred Freeman at Blanchester, Ohio
         Mr. Ken Shearwood and Mr. Don Caudel at New  Richmond, Ohio

      Illustrations and Graphical layout assistance:
         Dr. Robert Probst of the University of Cincinnati (DC) Design, Architecture, Art, and Planning
            (DAAP), for arranging the services of DAAP graduate students to prepare the illustrations
         Ms. Shereen Puthenpurackal, graduate student at UC-DAAR for preparing the stand-alone
         Mr. Abhijeet Bhattacharya, graduate student at UC-DAAR for developing the character-based
         Mr. James I. Scott of Shaw for performing the document setting and layout

Context-specific information and illustrations for inclusion into the document were provided by:
   Mr. Ira M. Cabin, Dixon Engineering
   Ms. Heather Himmelberger, RE., New Mexico Environmental Finance Center
   Dr.Yeongho Lee, RE., Greater Cincinnati Waterworks
   Mr. Adam Levine, Historical Consultant, Philadelphia Water Department
   Ms. Charlotte D. Smith, Consultant
   Mr. Gordon W Thompson, Shaw

Cover Photo Credits (starting from top left clockwise) are as follows:
   Rural water tank - photograph by Mr. James I. Scott
   Children drinking from a faucet- pictured are Mr. Ravi R. Panguluri and Ms. Isabella M. Panguluri
     - photograph by Ms. Jennifer S. Panguluri
   Small town picture - Aerial view of Stowe, Vermont - Royalty-free image from American Spirit
      Images purchased from www.fotosearch.com
   Operators flowing a hydrant - Montgomery County Sanitary Engineering Department Operators
     - photograph by Dr. Walter M. Grayman.


Chapter 1
In the United States, there are thousands of miles of
water distribution pipes which convey drinking water
to consumers. However, there are many changes that
occur within a distribution system that may result in
degraded water quality.  Suspended and/or dissolved
solids in finished water can settle under low-flow con-
ditions and can be re-suspended during high-flow con-
ditions.   Various disinfection agents  (e.g., chlorine,
chlorine dioxide, and chloramines) can react with or-
ganic matter contained in the source water and gener-
ate potentially harmful byproducts to which consumers
are exposed.  In addition, microorganisms can attach
to pipe surfaces, producing a complex microbiologi-
cal environment known as "biofilm."   Contaminants
may  infiltrate a distribution system during pipe breaks
or through finished water storage facilities. Some of
these undesirable water quality changes result in taste,
odor or red-water problems that can be detected imme-
diately. Potential contamination by pathogens (e.g., E.
coli or Salmonella) may only be identified by sampling
and analysis after a contamination event or following
a waterborne disease outbreak. In order to minimize
the degradation of water quality within distribution
systems, the United States Environmental Protection
Agency  (EPA) publishes drinking water regulations.
It is important that water distribution system operators
and water utility managers understand changes occur-
ring  in water distribution systems, the related water
quality concepts, and associated regulations in order to
maintain a high degree of water quality within a distri-
bution system.  As emphasized in this document, prop-
er operation and management of distribution system
components is essential to protect the customer against
both  aesthetic and public health threats that may result
due to undesirable  water quality changes in the distri-
bution system.

1.1  Purpose and Scope of the
EPA  has  developed this  reference guide to assist op-
erators  and managers  of
small- and medium-sized
public   water  systems
(PWSs).  It  presents  a
compilation of informa-
tion  designed to provide
small- and medium-sized
water  utility   operators
with  a  comprehensive
picture  of the water distribution system network. Be-
cause the technical background level of the target audi-
ence (small- to medium-size system operators and deci-
sion makers) varies widely, some very basic concepts
have been included in this document. For the purposes
of this reference guide, PWSs are interchangeably re-
ferred to as water utilities.

1.2 Graphical  Elements and
     Cartoon  Illustrations
To make this document appealing to a wide audience,
graphical elements (pictures, tables and blue sidebars)
and cartoon illustrations have been used throughout the
document.  Many of these graphical elements and car-
toons are borrowed or adapted from existing publica-
tions (as referenced). Others were developed exclusive-
ly for use in this reference guide.  Many of the cartoons
were developed to illustrate basic distribution system
concepts in a humorous manner but bear no relation to
any real individuals or organizations. Figure 1.1 shows
a "rogue's gallery" of the characters that populate this
Carl, a utility
                          Stan, a state
                     Fred, a federal
                 Dale, a small utility
            Liz,  a small utility
            laboratory technician
                                      -ji* '
                                     - ' A   *-
                               :i:i.. i i'"*?A.- '
                            ^"    /
                                       •;'i  Bob, a small
                                          utility operator
Figure 1.1 "Rogue's Gallery" of fictional
characters used in this reference guide.

manual and their roles.  In addition to these fictional
characters, other "stand alone" cartoons are also used
throughout the document as necessary. None of the car-
toon illustrations are meant to provide any "real-world"
solutions. The sole purpose of the cartoon illustrations
is to provide humor without offending any race, nation-
ality, gender, politics, or religion.

1.3  SmallWater,  USA- Problem
Every water distribution system is different in terms of
specific layout and operations. However, water distri-
bution systems  generally have the same components
and operate under similar principles and operational
strategies. SmallWater, USA is an example of a water
distribution system, utilized in this document to illus-
trate a drinking  water utility serving a small- to medi-
um-sized town.  This exam-
ple system includes  all
of the components that
are typically  found
in the majority  of
small- and medium-
sized  PWSs and is
used  to  illustrate
many of the  issues
and  potential  prob-
lems  facing  a small
water utility.  SmallWa-
ter, USA  problem scenarios
are used throughout this reference guide to explore a
number of water quality, operational, regulatory/com-
pliance, and institutional problems faced by many of
the small- and  medium-sized utilities in the nation.
At the end of each chapter,  one or more  SmallWater
problem scenario(s) are presented along with some
guidance on how to address these problems.

1.4  Content Development and
Between  January  and February of 2007,  during the
initial stages of development of this reference  guide,
several of the authors met with the staff at three small
water utilities to discuss their operational and manage-
ment procedures.  The various utility staff members
were very helpful  in discussing their approaches to
solving common problems. The authors also met with
various state regulatory agency personnel to get their
perspective on the critical issues facing small-commu-
nity water utility operators and managers.  In addition,
the authors consulted with several technical and  edi-
torial reviewers  to refine the material presented in the
document to make it suitable for the target audience.
These individuals are listed  in the Acknowledgement
                                                         section immediately preceding this chapter. The fol-
                                                         lowing is a brief description of the content in each of
                                                         the subsequent chapters of this reference guide.

                                                         Chapter 2 provides an overview of the water supply
                                                         and distribution process with an emphasis on how the
                                                         distribution system impacts the quality of water sup-
                                                         plied to the consumer.  First, the concept of "water
                                                         cycle"  is illustrated along  with strategies employed
                                                         by EPA to protect source water quality.  Subsequent-
                                                         ly, the process for treating,  stor-
                                                         ing and distributing water is
                                                         described. A brief history
                                                         of water treatment and
                                                         water quality regu-
                                                         lations is  provided
                                                         as it  relates to pro-
                                                         tecting water qual-
                                                         ity.   Summary sta-
                                                         tistics  documenting
                                                         the size,  source water,
                                                         and ownership of PWSs
                                                         is presented.  Finally, a listing of
                                                         common problems faced by small- and medium-sized
                                                         water utilities is presented along with the description
                                                         of SmallWater, USA.

                                                         Chapter 3 describes distribution system infrastructure
                                                         and how each component can potentially impact water
                                                         quality.  Each of the major distribution system com-
                                                         ponents is discussed in this chapter. The first subsec-
                                                         tion of this chapter discusses distribution system pipes
                                                         and how their functionality varies
                                                         with   connectivity,   place-
                                                         ment and configuration.
                                                         Pipe  types  and mate-
                                                         rial are also discussed
                                                         along with common
                                                         problems,   as  well
                                                         as     troubleshoot-
                                                         ing and pipe repair
                                                         techniques. Options
                                                         for minimizing pipe
                                                         leaks and water loss
                                                         during  distribution
                                                         system  line  breaks
                                                         are  also presented.
                                                         This is followed by a discussion on distribution sys-
                                                         tem pumps, storage facilities (tanks), valves, and hy-
                                                         drants.  Common problems associated with each of
                                                         these  components, along with  troubleshooting and
                                                         suggested maintenance techniques for these compo-
                                                         nents, are also  presented.   Finally,  the  distribution
                                                         system asset management concept is presented along
                                                         with a SmallWater, USA problem scenario.
Distribution System

Chapter 4 presents a summary of
the drinking water regula-
tions. The highlights of
the 1974 Safe Drinking
Water  Act  (SDWA)
and  its   subsequent
amendments are dis-   -•>
cussed.   The regula-
tions to  control  mi-
crobial and  chemical
contaminants are tab-
ulated. Public notifi-
cation and consumer
confidence rules  un-
der the SDWA are discussed.  Two SmallWater, USA
regulatory problem scenarios are presented.
                       Safe Drinking Water Act
                               Water Quality
Chapter 5 summarizes various distribution system wa-
ter quality issues such as taste, odor, and color.  The
concept of "biofilm" is presented, along with the fac-
tors  contributing  to
biofilm growth and
operational   factors
that could inhibit the
growth  of   biofilm.
Subsequently,  distri-
bution  system  water
quality  issues such as
disinfection byproducts
(DBFs), nitrification, pH
stability and scale forma-
tion are discussed.  These
sections are  followed by a
discussion on contamination
events including cross-connections, permeation/leach-
ing, intrusion/infiltration and reservoir/storage facility
contamination.  Finally, the concept of hydraulic mod-
eling is introduced followed by two SmallWater, USA
regulatory problem scenarios.

Chapter  6 provides  a  summary of the
available  methods  for  monitoring,
controlling, and securing dis-
tribution systems.  The physi-
cal  state  of the  distribution
system changes over time  and
techniques for monitoring pa-
rameters such as flow, veloc-
ity,  and pressure are  present-
ed.  Distribution system water
quality monitoring techniques
and methods for controlling a
distribution system are discussed.   Common control
automation equipment such as Supervisory Control and
Data Acquisition (SCADA) instrumentation,  SCADA
hardware, SCADA interface, and SCADA communica-
                              Water Distribution
tion media are presented. This is followed by a discus-
sion on distribution system vulnerabilities, operational
responses, and emergency response mechanisms.  Fi-
nally, two SmallWater, USA problem scenarios related
to monitoring, control and security are presented.

Chapter 7 contains a summary of operational, man-
agement and financial strategies to address distribution
system water quality issues.   Operational strategies
such as reducing water age,
adapting operations to meet          t,-v
demand, initiating or chang-
ing disinfectants, and con-
trolling corrosion  are pre-
sented. Financial strategies
such as obtaining loans and
grants through various gov-
ernment and private sources
are discussed.  Management
strategies such as regionali-
zation and change in ownership are presented.  Finally,
two SmallWater problem scenarios are presented.

Chapter 8 includes a bibliography for this reference
guide. Some of the documents included in the bibliog-
raphy are referenced within the text of this guide. The
references in the bibliogra-
phy contain additional
detailed  informa-
tion and provide
valuable    read-
ing material for
readers who wish
to pursue any of the
specific  topics  dis-
cussed in this guide in
greater detail.          Additional Information and
T ,u  A   i      * *          Bibliography
In the development of               J  r J
this reference guide, care has been taken to keep the
guide simple,  short, and concise.  The guide contains
additional references for supplementary reading mate-
rial (as necessary and appropriate).  Acronyms and ab-
breviations used in each chapter are defined in a sepa-
rate listing as well as at their first  occurrence in each
chapter. In addition, to help explain many of the con-
cepts, a variety of graphic illustrations, crossword puz-
zles and example problem scenarios have been utilized
throughout the document.


Chapter 2

The Supply,

Distribution, and

Quality  of Water:

An  Overview

Water is a renewable resource that is in continuous
movement at the  earth's surface (e.g., rivers, streams,
and oceans), below the ground in aquifers and in the
atmosphere. The natu-
ral movement of water
is powered by the sun
and the earth's gravity,
This natural continu-
ous movement of water
is called the hydrologic
cycle or the "water cy-
cle." In this cycle, wa-
ter precipitates as rain
and falls  onto surface
storage areas such  as
lakes,  rivers, streams,
and oceans. The water
on the land and these surface storage
areas infiltrates and recharges un-
derground  sources called aq-
uifers.   Additionally, the
water from the surface
sources and plants evaporates  to form rain-bearing
clouds. Figure 2.1 is a graphical representation of the
natural water cycle.

Aquifers (ground water) and rivers (surface water) are
the main sources of water for utilities in the United
States (U.S.).

2.1  Protecting  Source Water

During the natural cyclic movement and storage of wa-
ter in both surface and subsurface sources, water may
be exposed to a variety of natural or human activity-
related contaminants.  Depend-
ing upon the location, the source
water may be exposed to surface
or subsurface sources of physical,
chemical, biological and/or radio-
logical contamination. Examples
of contamination sources include:

  •  Rain water run-off collected by storm
     sewers (physical and/or chemical/biological

  •  Concentrated Animal Feeding Operations
     (biological and chemical contamination)

                    Agricultural Pesticide
                    and Fertilizer Application
                       (chemical contamination)
Figure 2.1 The Hydrologic Cycle or "Water
Cycle" (Adapted from: EPA, 2002f)

         •   Septic Systems and Leaking Sewers (biological

         •   Construction Activities (chemical

         •   Wastewater and Industrial Discharges (chemical
            and biological contamination)

         •   Mining Wastes (chemical and radiological

         •   Naturally occurring chemical and radiological
            material in contact with underground
            water resources (chemical and radiological

      These multiple risks to public health, illustrated in Fig-
      ure 2.2, are only a few of the potential sources of con-
      tamination that can threaten both surface and ground
      water supplies used by the water utilities.  EPA  man-
      dates various water quality standards and regulations
      that are  designed  to  serve as barriers to  the risk of
      source water contamination.

      If the amount (or concentration) of the contaminant
      material  present in the  source water supply exceeds
      drinking water standards, water utilities are required to
      treat the  source water to reduce (or eliminate) the con-
      taminant material to the required standard levels  prior
      to distributing the water to their customers.
2.2  Water Treatment, Supply and
Source water is often treated by unit processes  such
as coagulation, filtration, and disinfection to remove/
reduce the contamination, to meet the maximum con-
taminant levels (MCLs).  These treatment processes
are generally not considered to be part of the distri-
bution system.   The finished water may be directly
delivered  to the  consumer through the distribution
system or temporarily stored in underground/elevated
tanks before it is delivered to the  consumer through
the distribution system to  faucets  in their homes or
work places.  Figure 2.3 is a graphical representation
of a typical water supply system that uses a surface
water source.

A drinking water distribution system is a complex net-
work of pipes, tanks and reservoirs that delivers finished
water to consumers.  The consumers of water include:
residential households,  commercial businesses, indus-
trial users, and agricultural users.   Collectively, water
distribution system infrastructure consists of a variety
of equipment such as pumps, pipes, tanks, valves, hy-
drants and meters, that are built to  deliver water from
the surface (e.g., river)  and/or subsurface source (e.g.,
wells drilled into aquifers) to the customer. Figure 2.4
shows a schematic representation of a generic water
distribution system.
                                                                                             Agricultural Pesticide
                                                                                            & Fertilizer Application
      Figure 2.2 Multiple Risks to Public Health
      (Adapted from: EPA, 2002f)

Figure 2.3 A Typical Water Supply System Using Surface
Water as Source (Adapted from: EPA, 2002f)

      A more detailed discussion of the distribution system
      components is presented in Chapter 3.0 of this report.

      2.3  History  of Water Supply and
            Treatment in the United  States
      The first water supply utility was established in the U. S.
      in Boston, Massachusetts in 1652, for the purpose of
      providing domestic water and fire protection. Other
      cities followed Boston's example and established water
      utilities for fire protection and to provide commercial
      and residential water service. The first water treatment
      plant in the U.S. was constructed in Richmond, Virginia
      in 1832 and the second was constructed in 1855 in Eliz-
      abeth, New Jersey. The water treatment system in Eliza-
      beth consisted of a small charcoal sand and gravel filter.
      By 1860, only 136 water systems had been constructed
      in the U.S. Because most of the early utilities  supplied
      water from springs low in turbidity and relatively free
      from pollution, they were also relatively problem-free.
      By the end of the nineteenth century, however, water-
      borne disease had become a serious problem in indus-
      trialized watersheds. For example, during one year in
      the  1880s, the typhoid death rate was  158 deaths per
      100,000 in Pittsburgh, Pennsylvania.  This led to the
      more  routine use  of water treatment; by  1935, the ty-
      phoid death rate had declined to 5 per  100,000.  Another
      study  of typhoid case rates and associated death rates in
      the City of Cincinnati between 1898 and 1928 shows a
      significant decline in these rates after the city  initiated
      filtration in 1907,  and after implementation of chlorina-
      tion in 1915. Water treatment in the U.S. has proven to
   Source          Treatment           Distribution/Storage

s2ฃ2ws2ฃ2ฃ> — *•


Figure 2.4 A Schematic Representation of a Water
Distribution  System
                                                        be a major benefactor to the nation's public health. The
                                                        use of chlorine in particular has been recognized as a
                                                        breakthrough in public health.

                                                        2.4 History of Water Quality
                                                              Regulations  and  Standards in
                                                              the United States
                                                                           EDITORIAL PAGE
                                                            PHILADELPHIA  RECORD
                                                                     SUNDAY, MARCH 14, 1937
(Courtesy: PWD, 2007)

The first federal drinking water regulation was prom-
ulgated in 1912 under the Interstate Quarantine Act of
1893. At that time, interstate railroads provided a com-
mon cup for train passengers to share for drinking water
while on board. The Act prohibited this practice.  By
1962, several sets of federal drinking water standards
          Sorry, honey, the first drinking water
           regulation passed in 1912 under the
           Interstate Quarantine Act of 1893
       specifically prohibits the use of a "common
        cup" on carriers of interstate commerce!

                    Fix the leak, open the valve,
                   flush the hydrant, and take the
                    water samples by 4:00 pm.
      had been issued, but they applied only to interstate car-
      riers.  By the 1960s,  each of the states and trust ter-
      ritories had established its own drinking water regula-
      tions, although there were many inconsistencies among
      them.  Reported waterborne disease outbreaks had de-
      clined from 45 per 100,000 persons in 1938-40 to 15
      per 100,000 persons in 1966-70.  However, the annual
      number of waterborne disease outbreaks had stopped
      declining around 1951 and may have actually increased
      slightly. These conditions, in part, led to the passage of
      the Safe Drinking Water Act (SDWA) of 1974.

      The SDWA defines drinking water quality as a measure of
      its suitability for human consumption, based on selected
      physical, chemical, and biological characteristics.  The
      regulations established under the SDWA became the first
      set of national drinking water regulations. These regula-
      tions require that utilities meet specific guidelines and/or
      numeric standards for drinking water quality. The SDWA
      defines a public water system (PWS) as a system that pro-
      vides water for human consumption through pipes or other
      constructed conveyances, provided that such a system has
      at least 15  service connections or regularly serves an aver-
      age of at least 25 individuals daily for at least 60 days out
      of the year. The SDWA established two types of numeric
      standards.  The first is an enforceable standard commonly
      referred to as an MCL. The other (non-enforceable) stand-
      ard is referred to as a maximum contaminant level goal
      (MCLG).  MCLGs are set at a level at which no known or
  Water quality in the distribution system has been of major
  interest to regulators and drinking water utilities.  Main-
  taining a high level of water quality in the distribution sys-
  tem can pose a major challenge  to some drinking water
  utilities because of the age and type of pipes used in their
  system. Corroded and decaying pipes  may  deteriorate
  water quality significantly during transportation of water
  through the distribution system. Contaminants that can
  potentially increase in a distribution system include lead,
  copper,  disinfection byproducts  (DBFs),  and coliform.
  Cross-connections are another major source of distribu-
  tion system contamination.
anticipated adverse human health effects occur.

Where it is not economically or technologically feasible
to determine the MCL for a contaminant, an enforce-
able treatment technique (TT) is prescribed by EPA in-
stead of an MCL.  For example, Giardia lamblia is a
microbial contaminant that is difficult to measure.  To
ensure proper treatment, experimental work has been
conducted by EPA and others to establish optimum
treatment conditions.  EPA and other researchers have
identified treatment technologies for ensuring  proper
treatment. Therefore, the TT describes a specified pH,
temperature, and disinfectant concentration along with
a specified length of "contact time" to achieve a spe-
cific level of inactivation (or microbial kill).  EPA has
also set  operational conditions that systems must meet
to demonstrate removal by physical removal processes
(e.g., rapid granular filtration, membranes).

The major rules and requirements of interest to small-
and medium-system operators are discussed in Chapter 4
of this document.

  EPA has  identified  several  Best Available Technologies
  (DATs) under SDWA for the treatment of drinking  wa-
  ter.  The identified BATs include: Activated Alumina,  Co-
  agulation/Filtration, Direct Filtration, Diatomite Filtration,
  Electrodialysis  Reversal, Corrosion Control,  Granulated
  Activated Carbon, Ion Exchange, Lime  Softening, Reverse
  Osmosis,  Polymer Addition, and Packed Tower Aeration.
  Note that using BAT is not the same as employing speci-
  fied TT.  However, BATs can be used for requesting the
  issuance of variance or exemption.
2.5  Public Water System
There are nearly 160,000 water utilities in the U.S. These
water utilities vary greatly in size, ownership, and type
of operation. The SDWA defines PWSs as consisting of
community water systems (CWSs), transient non-com-
munity water  systems  (TNCWSs), and  non-transient
non-community water systems (NTNCWSs). A CWS
is a PWS which serves at least 15 service connections
used by year-round residents or regularly serves at least
25 year-round residents. An NTNCWS is  a PWS that is
not a CWS and it regularly serves at least 25 of the same
persons for more than six months per year. A TNCWS
is a not a CWS and it does not regularly serve at least 25
of the same persons for more than six months per year.
Figure 2.5 shows examples of this classification.

2.5.1  Type and Size of Systems
Of the nearly 160,000 water utilities in the U.S., 33 per-
cent are classified as CWSs, 55 percent are classified as
TNCWSs, and 12 percent are classified as NTNCWSs.
PWSs serve  297 million  residential, transient, and

                     Water System
 Water System (CWS)
   Municipal Systems
   Rural Water Districts
   Mobile Home Parks
                     Water System
                     • Office Buildings
                     • Schools
                     • Factories
                     • Daycare Facilities
 Water System
  • Restaurants
  • Parks
  • Motels
Figure 2.5 Classification ofPWSs in the U.S.

      commercial customers. PWSs servingfewerthan3,300
      people are categorized as small systems and those serv-
      ing 3,300 to 10,000 people are categorized as medium
      systems. Although a vast majority (98 percent) of sys-
      tems are categorized as small and medium, they serve
      only about a quarter of the U.S. population. Other size
      classifications such as that specified by the Small Busi-
      ness Regulatory Enforcement Act (SBREFA)  generally
      define small systems to include all distribution systems
      that serve less than 10,000 people. Figure 2.6 shows a
      distribution of PWSs by size in the U.S.
  "Consecutive systems" are those PWSs that receive some
  or all of their finished water from one or more wholesale
  systems. Delivery may be through a direct connection or
  through the distribution system of one or more consecutive

      As shown in Figure 2.6, a very large number of the
      PWSs in the U.S. are represented by small- and me-
      dium-size water utilities.  The large  number of small
      and medium utilities creates a major administrative and
      oversight challenge for state and federal water supply
      regulatory agencies.
                               I Small 501-3,300
                               I Large 10,001-100,000
U Very Small 25-500
D Medium 3,301-10,000
• Very Large >100,000

Figure 2.6 Distribution of PWSs by Size (EPA, 2007a)
                                                                                 We have 85 customers and we spent
                                                                                   1.4 million dollars to build this
                                                                                    double reverse osmosis system
                                                                     Wealthy Falls Water
                                                                     Treatment Plant
                                                             SmallWater, USA
                                                               Flea Market
                                                                                   I sure hope we can buy a spare
                                                                                  hydrant at the flea market,  I don't
                                                                                   think we can fix this one again
                   2.5.2 Type of Source Water Used
                   Some utilities rely primarily on surface water supplies.
                   while others rely primarily on ground water.  Surface
                   water is the primary source of 22 percent of the CWSs,
                   while ground water is used by 78 percent of CWSs.  Of
                   the TNCWSs and NTNCWSs, 97 percent are served by
                   ground water. In addition, many systems serve commu-
                   nities using multiple sources of supply such as a com-
                   bination of ground water and/or surface water sources.
                   In these systems, the mixing of water in the distribution
                   system poses a challenge for managing water quality.
                   Figure 2.7 shows  a distribution of PWSs by primary
                   source of water used.

                   As shown in Figure 2.7, the vast majority of small and
                   medium water utilities in the U.S. use ground water.

     Ground Water Systems
Surface Water Systems
 Figure 2.7 Distribution of Small- and Medium-Sized
 PWSs by Source of Water Used (EPA, 2007a)

      2.5.3 Type of Ownership
      The ownership of water utilities in the U.S. is also di-
      verse and has a long history of local government control
      over operation and financial management, with varying
      degrees  of oversight and regulation by state and fed-
      eral government. The water utilities serving cities and
      towns are generally administered by  departments of
      municipalities or counties (public systems) or by inves-
      tor-owned companies (private systems).

      Public systems are predominately owned by local mu-
      nicipal governments, and serve approximately  78 per-
      cent of the total population. Approximately 82  percent
      of urban water systems (those serving more than 50,000
      persons) are publicly owned.

      About 33,000 privately owned water systems serve the
      remaining 22 percent of people served by CWSs. Pri-
      vate systems are usually investor-owned in the larger
      population size categories, but can include many small
      systems  as part of one large organization. These inves-
      tor-owned utilities are in business to generate profit for
      their shareholders. In the small-and medium-sized cat-
      egories,  the privately owned systems tend to be owned
      by homeowners, associations, or developers.

      Other types of system owners include several classifica-
      tions of  state-chartered public corporations,  quasi-gov-
      ernmental units, and municipally owned systems that
      operate  differently from traditional public and private
      systems. These systems include special districts, inde-
      pendent  non-political boards, and state-chartered cor-
      porations. Figure 2.8 shows the  distribution of PWSs
      by ownership.

      Figure 2.8 indicates that the vast majority of small and
      medium water utilities in the U.S. belong in the private
      ownership category, followed by the local government
      category. The difference in financial structure between
D Private
D Public/Private
D State Government
• Unknown
D Federal Government
• Local Government
DTribal Government
                          Figure 2.8 Distribution of Small- and Medium-Sized
                          PWSs by Ownership (EPA, 2007a)

                          the government and private entities makes the manage-
                          ment of small system operations challenging.

                          2.6 Common Problems  Faced by
                               Small and Medium Utilities
                          The problems faced by operators of a small- and me-
                          dium-sized utility are as diverse as the system statistics
                          presented in Section 2.5. However, for the purposes of
                          this document, the common problems have been broad-
                          ly categorized as follows:
                               Water Quality



                         Key considerations  associated with the management
                         of these problems for small-and medium-sized utilities
                         will be the focus of this document.

                         2.6.1 Water Quality Problems
                         Water quality issues faced by small-and medium-sized
                         utilities are geographically diverse and complex.  The
                         common consumer-reported problems include  taste,
                         odor, and color. These problems generally do not have
                         an immediate impact on consumer health or result in
                         regulatory non-compliance. However, they must be ad-
                         dressed quickly to retain customer support for the sys-
                         tem. Examples of taste and odor issues reported by the

                  "This should take care of
                      the smell issue!"
customers include:

   •  earthy smell

   •  chlorine smell

   •  rotten egg smell

   •  petroleum smell

   •  fishy smell

   •  metallic taste

Examples of common color issues reported include:

   •  red water

   •  green water

   •  black water

   •  milky water

2.6.2 Operational Problems
Common operational problems faced by small-and me-
dium-sized utility operators include:

   •  pressure problems

   •  main breaks, leaks

   •  valve  problems

   •  excessive
     sediments in pipes
     and reservoirs

   •  cross-connection
     and backflow

   •  replacement and/or repair of tanks and water

   •  network and supply expansion

   •  adequate fire flow

2.6.3 Regulatory/Compliance Problems
Common regulatory and compliance issues faced by
small-and medium-sized utilities include:
Monitoring and
reporting problems

MCL exceedances (e.g.,
elevated lead, copper,
and arsenic levels)

Treatment technique

Loss of disinfectant
2.6.4 Institutional Problems
Common institutional issues faced by small-and me-
dium-sized utilities include:

  •  money constraints (small population and low
     water rates)

  •  limited asset management

  •  poorly trained and low-paid operators (even

  •  inadequate metering

  •  unaccounted-for water loss

  •  lack of system security
                                                                I'm using a miracle fertilizer.
                                                             Hopefully, we'll have enough money
                                                              to buy a water tank next summer.
                                             To focus on these problems and to evaluate potential so-
                                             lutions, a hypothetical example of a community with a
                                             small water utility called "SmallWater, USA" has been
                                             developed. The problems and solutions discussed and
                                             presented in this document will be related to SmallWa-
                                             ter, USA.  The following section presents a brief over-
                                             view of SmallWater, USA.
                                                         2.7  SmallWater, USA
                                                   SmallWater is a hypothetical rural town in Midwestern
                                                   U.S. The current population is about 2,700 with a small
                                                   commercial downtown area and a small industrial park.
                                                   The original water system was installed in the 1930s us-
                                                   ing cast iron pipe and was served by a well field on the
                                                   western edge of the town and an adjacent standpipe. The
                                                   town grew with additional development in the 1970s to
                                                   the north of the original town using  asbestos-cement
                                                   pipe.  In the 1990s, the well supply became inadequate
                                                   and an alternate source was developed in the form of an
                                                   interconnection to the surface water supply for a larger

      system located to the southeast.  The well  field was
      maintained as a supplemental and emergency supply.
      At that time, additional development also occurred in
      the form of a subdivision at the eastern edge of the town
      and on the ridge to the north of the town.  A pump sta-
      tion was built to serve this high zone (ridge) and a small
      elevated tank was constructed. A commercial develop-
      ment (shopping  center)  was also added to the system
      and served via a pressure-reducing valve  (PRV) from
      the high zone. Polyvinyl chloride (PVC) pipe was used
      for these modifications. Figure 2.9 is a schematic of the
      water system in SmallWater, USA.

      SmallWater, USA purchases finished water from the
      adjacent system via the  interconnection. Well water is
      chlorinated without any additional treatment. At the cur-
      rent time,  the town uses  an average of 210,000 gallons/
      day with approximately  70 percent of that total attribut-
      ed to residential use and the remainder for commercial.
      industrial, and institutional use. Maximum daily usage
      is approximately 400,000 gallons. Total revenue for the
      water utility is approximately $250,000/year.  The wa-
      ter system is run by the  town water board. Employees
      include a full-time clerk, a full-time water director and
      a part-time assistant.
The SmallWater, USA scenario will be used in this refer-
ence guide to explore a number of water quality, operation-
al, regulatory/compliance, and institutional problems faced
by many small- and medium-sized utilities in the U.S.
                    So what is the solution
                      to our problem?
                                                                                  Land Use Category


              Well Field
              (Stand pipe)
      Figure 2.9  SmallWater, USA -Schematic Layout

        The Supply, Distribution, and  Quality  of
                        Water:  An Overview
2 Regulatory acronym for water system serving
  restaurants, parks, motels that serve different
4 U.S. City where first water utility was estab-
6 Term for preventing source water contamina-
7 Regulatory acronym for utilities serving 25 or
  more people year round
8 U.S. City where first water treatment plant was
9 Regulatory acronym for expressing the
  enforceable limits for a particular contaminant
        1  Term for natural movement of water from
          rains, to lakes and streams, and evaporation
        3  Regulatory acronym for water system
          serving schools, hospitals and factories that
          have their own water supply and serve the
          same people for at least six months in a
        5  Term for microbial organisms that attach to
          interior pipe surfaces
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                                                                    :uo!in|os PJOMSSOJQ


Chapter 3

Distribution  System


Distribution system infrastructure consists of a network
of pumps, pipes, tanks, valves, hydrants, and meters
through which finished water is supplied to customers.
This infrastructure is designed to deliver water to the
customer. The physical integrity of the distribution sys-
tem, from entry point to the customer's faucet, is a pri-
mary barrier against the entry of external contaminants.
Figure 2.4, in the previous chapter, showed a schematic
representation of a typical water distribution system.

A variety of components and materials make up a drink-
ing water distribution system. These include: (1) pipes,
including mains and service lines; (2) fittings and ap-
purtenances such as crosses, tees, ells, hydrants, valves,
and meters; (3)  storage  facilities including reservoirs
(underground, open,  and covered), elevated  storage
tanks, ground level storage tanks, and standpipes; and
(4) backflow prevention devices.

Table 3-1 provides  examples of the   infrastructure
components and the  common materials of construc-
tion. These components serve as a physical barrier to
protect the distribution system water quality from ex-
ternal contamination threats. For example, the piping
material and fittings serve to protect the water from ex-
ternal contamination  sources such as soil, ground wa-
ter, sewer exfiltration, surface runoff, human activity,
animals, insects, microbial  pathogens,  and other life
forms.  The premise plumbing and storage facilities
are designed to  protect from air contamination, rain,
algae, surface runoff, human activity, animals, birds,
insects and other sources of non-potable water.

3.1 The Impact of Distribution
     System on Water Quality
Although water entering the distribution system may
meet the regulatory standards, water quality may de-
grade during  transportation within the  distribution
system before reaching the consumer.  Some of these
undesirable water quality changes such as taste, odor
or red-water problems can  be  detected immediately,
whereas others may only be identified by sampling and
analysis. A waterborne outbreak caused by organisms
such as E. coli or Salmonella, for example, may be later
traced back to accidental contamination of water in the
distribution system. A variety of components make up
the physical barrier that protects against the deteriora-
tion of water quality in a distribution system.  In ad-
dition, the proper management of these components is
essential to protecting the customer against both aes-
thetic and public health threats to distribution system
water quality.  This chapter presents an overview of the
key distribution system infrastructure components, the
common problems associated with these components,
and some potential solutions to these problems. Spe-
cifically, the following infrastructure components are
discussed in this chapter:
   •  Pipes
   •  Pumps
   •  Storage facilities
   •  Valves
   •  Hydrants
   •  Water meters and service lines
Table 3.11nfrastructure Components (NRC, 2006)
Pipe wrap and coatings
Pipe linings
Service lines
Customer building plumbing
Fittings and appurtenances (meters, valves,
hydrants, ferrules)
Storage facility walls, roof, cover, vent hatch
Backflow prevention devices
Gaskets and joints
Asbestos cement, reinforced concrete, steel, lined and unlined cast iron, lined
and unlined ductile iron, polyvinyl chloride (PVC), polyethylene and high-den-
sity polyethylene (HOPE), galvanized iron, copper, polybutylene, and lead
Polyethylene, bitumastic, cement-mortar
Epoxy, urethanes, asphalt, coal tar, cement-mortar, plastic inserts
Galvanized steel or iron, lead, copper, chlorinated PVC, cross-linked polyethyl-
ene, polyethylene, polybutylene, PVC, brass, cast iron
Copper, lead, galvanized steel or iron, iron, steel, chlorinated PVC, PVC,
cross-linked polyethylene, polyethylene, polybutylene
Brass, rubber, plastic
Concrete, steel, asphalt, epoxy, plastic
Brass, plastic, stainless steel
Rubber, leadite (a lead substitute), asphalt, plastic

                     Whoops... I  should V
                       have called 811!  J
The U.S. Federal Communications Commission in
March 2005 made 811 the universal number for
coordinating location services for underground public
utilities. This was required by the Pipeline Safety
Improvement Act of 2002.

      3.2  Distribution System Pipes
      Pipe materials used by the water utilities have changed
      greatly over time. Cast iron pipe (lined or unlined) has
      been largely phased out primarily due to its suscepti-
      bility to both internal and external corrosion.  Early
      on, ductile iron pipe (with or without a cement lin-
      ing) took  its  place because of its durability, strength
      and good  resistance to external corrosion from soils.
      However,  ductile iron pipe also needs corrosion pro-
      tection in  certain soils and may require multiple types
      of joints.   Subsequently, concrete, asbestos cement,
      and polyvinyl chloride (PVC) plastic pipe were used
      to replace metal pipe because of their relatively good
      resistance to  corrosion.  More recently, high-density
      polyethylene (HDPE) pipe is being used as a replace-
      ment because of its ease of installation, toughness,
      flexibility, and corrosion resistance.

      3.2.1 Pipe Connectivity, Placement and
      Distribution  system pipe networks  consist of  wa-
      ter "mains," also called "primary feeders" or "trunk
      lines." The mains are generally  12 inches or greater
      in diameter (for small systems, the mains may be only
      6- to 8-inches in size), and carry water from the treat-
      ment plant to the local  service areas where they are
      connected to smaller-diameter "branches" also called
      "secondary feeders." The branches that are tied  into
      the mains  are usually greater than six inches in diam-
      eter.  At the other end, the branches are tied to other
      smaller diameter pipes (4, 6 or 8 inches) that connect
      with  service connections to  customers (residential,
      commercial, and industrial). Water pipes are typically
      placed three to  six feet below ground level to protect
them from traffic, freezing, damage from excavation
and  construction activities.  These pipes are placed
within the public right-of-way so that workers can in-
stall service connections for all potential water users.

Branch and grid/loop are the two basic configurations
used by most water distribution systems.  A branch
system is similar to  a tree where smaller pipes branch
off larger main pipes (similar to a tree trunk) through-
out the  service area.   This  type of  system is most
frequently  used in rural areas, and generally in  this
type of system, water has only one pathway from the
source to the consumer. A grid/loop system consists
of interconnected pipe loops throughout the area to be
served.  In this type of system, there are several path-
ways that the water  can follow from the source to the
consumer.  A grid/loop system is the most widely used
configuration in medium-and large-sized utilities.  The
grid/looped systems provide a high degree of reliabil-
ity should  a line break occur, because the break  can
be isolated with little impact on customers outside the
immediate  area. Figures 3.1 and 3.2 depict a branched
and grid/looped distribution system, respectively.
Figure 3.1 A Branched Distribution System
Figure 3.2 A Grid/Looped Distribution System

      3.2.2 Pipe Material
      Distribution system pipes are generally made of asbes-
      tos cement, unlined cast iron, cement-mortar-lined cast
      or ductile iron, plastic (PVC,  HDPE), reinforced con-
      crete, steel or fiberglass.  Pipes used in water systems
      must be approved for potable water use.  NSF Interna-
      tional, American National Standards Institute (ANSI),
      American Society for Testing Materials  (ASTM), and
      Underwriters Laboratory (UL) are among the organiza-
      tions that test and approve pipe for potable water ap-
      plications.  Figure 3.3 shows the NSF potable water use
      approval depicted on a PVC pipe.
                                           Additional  Information
                                           Pipe Material Voluntary
                        AWWA - M9, Concrete Pressure Pipe, Second Edition,
                        AWWA - Mil, Steel Pipe—A Guide for Design and In-
                        stallation, Fourth Edition, 2004
                        AWWA - M23, PVC Pipe—Design and Installation,  Sec-
                        ond Edition, 2002
                        AWWA - M41,  Ductile-Iron Pipe and Fittings, Second
                        Edition, 2003
                        AWWA - M55, PE Pipe—Design and Installation, First
                        Edition, 2006
Figure 3.3  NSF-Approved PVC Pipe for Potable Water

      The condition of pipe, source water quality, and the soil
      conditions around the buried pipe can negatively impact
      the water quality. Degradation of plastic (PVC or HDPE)
      pipes located in soils contaminated with organic  com-
      pounds may result in softening of the pipe wall and subse-
      quent permeation of organic matter through the pipe wall,
      leading to contaminated water.  Table 3.2 presents a sum-
      mary of potential negative impacts to water quality based
      on pipe material and changes in source water quality.

      As presented in Table 3.2, depending upon the pipe ma-
      terial and relative changes  in source water quality, the
      pipe wall interactions may  negatively impact the water
      quality. Figure 3.4 depicts the various pipe wall inter-
      actions that may adversely affect water quality.
                                               Surface   (Chemicals Biological)
                                         Paniculate*  H*tซfOtfOph*   Colilorma
                       Figure 3.4  Pipe Wall Interactions that Affect Water
                       Quality (Adapted from: MSU, 2005)
      Table 3.2 Potential Negative Impacts to Water Quality Based on Pipe Material and Changes in Water
      Quality (Adapted from AwwaRF, 2005)
                Pipe Material
       Unlined cast iron, steel, or old
       galvanized steel
       Cement-mortar lined ductile iron
       Asbestos cement (Transite)
       All pipe types including fiber glass
        Changes in Water Quality
1) pH increase or decrease, or
2) Alkalinity decrease, or
3) Dissolved oxygen increase or decrease
                                      Chlorine residual increase
                                      1) pH decrease, or
                                      2) Alkalinity decrease
1) pH decrease, or
2) Alkalinity decrease
                                      Chlorine residual decrease
     Potential Negative Impacts
May result in discolored water
                                                                             May mobilize iron and/or manganese
                                                                             oxides and result in discolored water
                                        May trigger localized pH and alkalin-
                                        ity increases with associated negative
                                        impact of discolored water
May trigger localized pH and alkalin-
ity increases and increased levels of
asbestos fibers in water
                                        May result in increase in microbiological
                                        population such as HPCa and possibly
                                        coliformb levels
       aHeterotrophic Plate Count —A bacterial counting procedure used to estimate bacterial density in a water sample. Other names for the procedure
          [within the water industry] include total plate count, standard plate count, or plate count.
       bColiform - A specific class of bacteria found in the intestines of warm-blooded animals and people. The presence of conform bacteria in water
          indicates that there is a possibility, but not a certainty, that disease-causing organisms may also be present in the water.

      3.2.3 Common Problems, Troubleshooting and
            Pipe Repair
      Excessive scale buildup, corrosion, pipe leaks and main
      breaks are the most  common  pipe-related problems
      faced by water utilities. Excessive scaling in pipe results
      in loss of delivery capacity overtime. Internal corrosion
      of pipes can result in discolored water or high lead and
      copper levels.  For example, reddish-brown water is the
      result of corrosion of iron pipes, bluish stains on fixtures
      are the result of corrosion of copper lines, and black wa-
      ter generally results from sulfide corrosion of copper or
      iron lines, or can be the result of precipitation of natural
      occurring manganese in water. External corrosion leads
      to pipe leaks and water main breaks. There are several
      types of leaks, including valve  leaks and service line
      leaks, but in most cases the largest amount of water is
      lost through water main leaks. Leaks occur due to fac-
      tors such as pipe material, pipe  composition, pipe age.
      finished water quality, temperature, pressure, and pipe
      joining methods. External conditions, such as contact
      with other structures (that can cause movement or elec-
      trical current flow), stray  electric currents, traffic load.
      aggressive  soils, vibrations,  and frost conditions can
      also contribute to leaks. Pipes also break due to factors
      such as water  freezing, traffic load, and corrosion.  In
      addition, pipes may be defective, installed improperly,
      or simply not strong enough to handle pressure surges.
                   Somebody get me a
                       ! clamp, quick! Minimizing Leaks and Water Loss
      Leakage results in loss of revenue to a utility.  Larger
      leaks are usually detected faster, because they usually
      lead to water reaching the surface which results in quick
      identification,  isolation and repair.  Small undetected
      leaks can often lead to large amounts of water loss over
      time. Leak detection methods usually involve sonic or
      ultrasonic leak-detection equipment, which identifies
      the sound of water escaping a pipe.  These devices in-
      clude pin-point listening devices that make contact with
      valves and hydrants, or geophones that listen directly
      to sound moving through the ground. In addition, there
      are other devices that can listen at two locations simul-
      taneously  to correlate "leak" sounds and determine
      the exact leak location.  Leak detection efforts should
  Pipe Leak Management by a Small System (EPA, 2002c)
  Gallitzin, a small town in western Pennsylvania (popula-
  tion -2,000),  services approximately 1,000 connections.
  The system was experiencing water  losses exceeding 70
  percent. In November 1994, the system was using an av-
  erage of 310,000 gallons per day. Gallitzin experienced a
  peak usage in February 1995 of 500,000 gallons per day.
  The water authority identified five major problems in the
  system: 1) high water loss, 2) recurring leaks, 3) high over-
  all operational costs, 4) low pressure complaints and 5) un-
  stable water entering the distribution system.
  The water utility decided to implement a  comprehensive
  program for water leak detection. For this purpose, the
  utility  first developed accurate water production and dis-
  tribution records using 7-day meter readings at the plant
  and pump station. A system map was then created to lo-
  cate leakage. Through the use of a leak detector, the utility
  was able to identify approximately 95 percent of its leaks.
  Thereafter, the utility initiated a leak repair program and
  a corrosion control program at the Water Treatment Plant.
  Gallitzin was one of the first systems to receive technical
  assistance from the Pennsylvania Department of Environ-
  mental Protection Small Water Systems Outreach Program.
  The training helped the authority repair distribution system
  leaks,  replace inaccurate  meters, and improve customer
  billing. Accuracy of water meters is critical for determin-
  ing water loss as part of a good leak management program.
  By November  1998, 4 years after implementation of the
  program, the system delivered an average of 128,000 gal-
  lons per day to the town—down from 310,000 gallons per
  day in November 1994. Unaccounted-for water dropped
  to only 9 percent. The financial savings from the program
  have been highly beneficial. The city saved $5,000 on total
  annual chemical costs and $20,000 on total annual pow-
  er costs between 1994 and 1998. The significant savings
  helped the utility keep water rates down.
focus on the portion of the system where the greatest
problems are expected. These problem areas generally
include areas with excessive leak and break rates, high-
pressure areas, and areas where pipes are old. As a gen-
eral guideline, a water conservation and leak detection

                   Additional  Information
                   Leak Detection and Water
  A National Drinking Water Clearinghouse (NDWC) Tech
  Brief on leak detection and water loss control can be ob-
  tained online from: http://www.nesc.wvu.edu/ndwc/pdf/
  AWWA - M36, Water Audits and Leak Detection, Second
  Edition, 1999

    program should be implemented when the "unaccount-
    ed-for" water (water produced - metered water usage at
    customer locations) exceeds 15 percent. Distribution System Line Breaks
    Distribution system pipes  can break for a variety of
    reasons such as excessive traffic load, extremely cold
    temperatures, accidents during excavation/construction
    activities, pressure surges,  and corrosion.  Procedures
    for dealing with major main breaks are usually outlined
    in a utility's emergency response plan (ERP).  If a util-
    ity suffers a major main break, law enforcement, fire
    protection, and city officials should be notified since the
    leak may pose significant hazard to life or property.  Af-
    fected customers should be notified since valves must
    be shut off to isolate the break and to perform needed
    repairs. For smaller leaks, it is preferable to perform the
    repair without shutting off the water service.  Allowing
    a line to remain under pressure prevents back siphoning
    and back pressure that can cause contaminants to enter
    into the pipe.  In some cases, nearby hydrants can be
    opened to lower the water pressure to facilitate the re-
    pair.  If the pipe break is small, it can be repaired using
    a pipe clamp or sleeve that serves as a "bandage."  For
    larger breaks, portions of pipe are cut off and replaced
    by new sections.  As a general rule when conducting
    repairs, safety precautions are necessary with regard to

                 Additional Information

                 Line Repair and
A NDWC Tech Brief on repairing distribution line breaks
can be obtained online from: http://www.nesc.wvu.edu/
AWWA -  M28, Rehabilitation  of Water Mains, Second
Edition, 2001
AWWA -  M22, Sizing Water Service  Lines and Meters,
Second Edition, 2003
trenching and shoring, in addition to following proper
procedures for pipe installation and repair.

Table 3.3 summarizes some of the common problems
that lead to pipe failures for pipes of differing materi-
als.  These include some of the principal factors, but
they are not the only factors that act individually or in
combination to cause a main break.  Other factors could
include a street excavation that accidentally disturbs a
water main or the misuse of fire hydrants.

3.3  Distribution System Pumps
Within a distribution system,  pumps are used  to dis-
charge water  under pressure to  the pipe network, to
boost pressure within a system and also to lift water
to a higher elevation where it can then be delivered by
gravity (e.g., elevated water storage tanks).  Pumps can
be classified into two basic groups: positive displace-
ment and variable displacement pumps.  A positive
displacement pump delivers the same volume or flow
of water against any "head" within its operating capac-
ity. Head is the vertical distance between a pump and
water outlet, usually measured in feet or converted and
expressed in equivalent pressure scale.  Examples in-
clude: piston pumps,  screw pumps, diaphragm pumps
and gear pumps. Variable displacement pumps  deliver
water with the volume or flow varying inversely with
the operating  head (i.e., the greater the head, the less
the volume of the flow). Examples include: centrifugal
pumps, jet, and airlift pumps.  Appropriate pumps are
selected based on the desired application.

Centrifugal pumps are used widely in water distribution
systems because of several advantages including:  1)
low cost and small footprint for a given capacity, 2) a
rotary mechanism that allows for adaptability to high-
speed driving mechanisms  such as electric motors and
gas engines, 3) simple mechanism,  easy for operations
and repair, and 4) safety against damage from high-
pressure because of limited maximum pressure that can
be generated.
     Table 3.3 Common Problems that Lead to Pipe Failure for Various Pipe Materials (NRC, 2006)
Pipe Material (common sizes) Common Problems
PVC and Polyethylene (4-36 in.)
Cast/Ductile Iron (4-64 in.)
(lined and unlined)
Steel (4-1 20 in.)
Asbestos-Cement (4-35 in.)
Concrete (12-1 6 to 144-1 68 in.)
(prestressed or reinforced)
Excessive deflection, joint misalignment and/or leakage, leaking connections, exposure
to sunlight, high internal water pressure or frequent surges in pressure, exposure to
solvents, manufacturing flaws
Internal corrosion, joint misalignment and/or leakage, external corrosion, leaking connec-
tions, casting/manufacturing flaws
Internal corrosion, external corrosion, excessive deflection, joint leakage, imperfections
in welded joints
Internal corrosion, cracks, joint misalignment and/or leakage, small pipe can be dam-
aged during handling or tapping
Corrosion in contact with ground water high in sulfates and chlorides, pipe is very heavy,
alignment can be difficult, settling of the surrounding soil can cause joint leaks

      Many brands of centrifugal pumps are available in the
      U.S. with capacities  ranging from a few gallons per
      minute (gpm) to several thousand gpm. Working heads
      can range between 5  to 700 feet, but the efficiency of
      each pump is limited to a narrow range of discharge
      flows and head.  Careful consideration must be given to
      these factors prior to pump selection.
              'We got the pump, and the
              ,    horses to power it!
      3.3.1 Common Problems, Troubleshooting and
            Maintaining Pumps
      During startup, centrifugal  pumps require  "priming."
      Priming is a procedure in which the pump is filled with
      water before turning the switch on.  The unit does not
      operate efficiently if it is not properly primed. In gener-
      al, pumps have an adjacent priming chamber that draws
      water when the pump is turned on to keep the impeller
      submerged.  After priming, the pump must be started
      with the  discharge valve fully closed.  Thereafter, the
      discharge valve must be opened slowly to  allow any air
      in the system to  escape and prevent water hammer or
      pressure surges. A surge of pressure occurs when a valve
      is suddenly closed or opened. This surge can cause the
      pipes to vibrate or create a hammering  noise. Also, at
      shutdown or during power failures, the discharge valve
      must be programmed to close in order to avoid backflow
      and prevent the impellers from running in reverse.

      Because  of the variety of pumps available, individual
      procedures for proper operation of each pump vary by
      manufacturer.  A utility operator should refer to manu-
      facturer instructions while operating and troubleshoot-
      ing the pumps. Centrifugal pumps require regular in-
      spection and maintenance. Bearings on the motor may
      become worn and must be checked and kept well-lubri-
      cated.  The packing seals must be examined for wear
      due to friction that can result in pump leakage. Bearing
and motor temperature must be monitored for excessive
heat.  If a surface is substantially hotter than normal,
the unit must be shut down and examined for the cause.
Any unusual noises or vibrations from the pump should
also be thoroughly investigated by shutting down the
unit first. Prior to performing any maintenance activity
on the pump, the pump must be shut down and drained
of all liquids before servicing. Electrical safety pro-
cedures must also be followed while  servicing motors.
All safety instructions provided by  the manufacturer
must be followed during the performance of mainte-
nance activities.
                                                                             Additional Information
                                                           AWWA - Water Transmission and Distribution: Principles
                                                           and Practices of Water  Supply Operations, 3rd edition,
                                                           AWWA- Design and Construction of Small Water Sys-
                                                           tems, 2nd edition, 1999
3.4  Distribution System Storage
Distribution system storage facilities (tanks and reser-
voirs) are necessary to accommodate peak flow (equal-
izing  storage),  emergency demand, and  firefighting
capabilities. In addition, they help maintain uniform
pressure and allow for reduction in the size of distri-
bution mains that would otherwise be  much larger to
accommodate peak flow requirements. Storage also re-
duces pumping costs under peak energy periods. Gen-
erally, these storage facilities are designed  and located
such that they can provide water at the required pres-
sure to the farthest location in the service area.

3.4.1  Types of Storage Facilities
Ground level reservoirs and tanks, elevated tanks  and
hydro-pneumatic tanks are designed for multiple uses
including:  equalizing storage,  maintaining  pressure
in the  system, and providing firefighting capabilities.
Equalizing storage is necessary when the source pump
capacity is less than  the peak system  demand.  This
storage is also essential for water production facilities
to run at a constant rate. Smaller distribution systems
with wells and relatively flat topography  may use  a
hydro-pneumatic tank to maintain water pressure.  A
hydro-pneumatic tank is an air-pressurized water tank.
The air in the tank acts as a cushion that can exert or
absorb pressure as required. The two common methods
employed for air-charging the tanks are: motor-driven
air compressors and hydraulic-powered air chargers.

                           I am thankful that you guys
                          approved our funding request
                            perform some minor repairs
                                  to this tank.
     The storage volume requirements for tanks are classi-
     fied by function: operating, equalizing, fire and/or emer-
     gency, and dead storage volume.  The typical minimum
     municipal fire flow requirement for a single-family resi-
     dential area is 500 to 1,000 gpm for two hours, which is
     equivalent to a minimum storage requirement of 60,000
     to 120,000 gallons. For commercial and industrial ar-
     eas, the fire flow requirement ranges between 2,000 and
     8,000 gpm for several hours which is  equivalent to a
     storage requirement of -500,000 gallons to over a mil-
     lion gallons.  Some local fire and state agencies allow
     for combining fire and emergency storage requirements.
     Figure 3.5 illustrates the typical storage tank volume de-
     sign parameters.
                                    Water In/Out
Figure 3.5 Storage Tank Volume Design Requirements
Depending upon the size and location-specific require-
ments, tanks may be constructed using steel (welded or
bolted, carbon or stainless), concrete, fiberglass, or plas-
tic (polyethylene, polypropylene). The type of material
used for the tank depends upon many factors including:
1) location of the water tank (indoors, outdoors, above
ground or underground), 2) volume  (larger tanks are
generally made of steel), 3) temperature and wind in
the area where water will be stored (concern for freez-
ing and structural strength requirements). In addition
to selecting appropriate tank material, all piping, joints
and fittings should conform to regulatory design speci-
fications.  Steel tanks are most widely  used  by  water
utilities in the U.S. Steel tanks are required to be painted
and to have cathodic protection to resist corrosion.
                    Additional Information
                    Storage Tanks
  AWWA - M25, Flexible-Membrane Covers and Linings
  for Potable-Water Reservoirs, Third Edition, 2000
  AWWA - M31, Distribution System Requirements for Fire
  Protection, Third Edition, 1998
  AWWA - M42, Steel Water-Storage Tanks, First Edition,
3.4.2 Common Problems, Troubleshooting and
      Maintaining Tanks
Water storage facilities (tanks) must  have covers  or
hatches that keep out birds,  rodents, insects, dust and
surface runoff. They must also have a screened vent
which allows air to enter and leave as the water level
drops or rises in the tank.  Outside access to the stor-
age facility must be lockable and weather-tight.  Lack
of proper hatches and vents may result in dead animals
and/or birds floating in the tank which can create serious
health problems.  Tanks should be routinely inspected
(for corrosion and structural integrity) and cleaned. Wa-
ter tanks are confined spaces and a confined-space warn-
ing label must be placed on tank access.  Confined-space
entry procedures must be followed by anyone entering
the tank. For larger tanks,  commercially trained divers
and/or remotely controlled underwater robotic systems
can be used for inspection and/or cleaning. The use of
divers and/or robotic devices requires special precau-
tions and procedures, especially if the tank is allowed to
remain in service during inspection/cleaning procedures.

Tanks that are improperly operated can lead to excessive
"aging of water" or areas of poor circulation. Excessive
storage time can lead to a  loss  of disinfectant residual
(chlorine/chloramine) which can result in bacterial re-

      growth. In addition, the disinfectant can react with nat-
      urally occurring organic matter to form greater levels of
      undesirable byproducts that may pose long term health
      problems. Poor circulation can lead to "dead" or stat-
      ic zones where the water may be much older than the
      average age in the storage facility.  Stratification is an
      example of poor mixing where the water age and char-
      acteristics vary in the vertical direction in the tank. This
      is most common in tall standpipes and in tanks where
      there is insufficient energy in the inflow during the fill
      cycle to create a well-mixed tank. Water aging can be
      reduced by changing the tank operation so that there is
      a greater exchange of water between the tank and the
      distribution system. Mixing problems can frequently
      be relieved by modifying the inlet-outlet configuration
      and/or increasing the inflow rate and velocity.

      3.5 Distribution System Valves
      Valves are critical for management of the distribution
      system.  Valves control flow/pressure, and isolate por-
      tions of the water distribution system for servicing. If
      valves are properly placed, distribution system pipe re-
      pairs and maintenance can be conducted with minimal
      loss of service to the customer.  Most valves require
      some mechanical or externally devised system to open/
      close or change the position of the valve. Manually  op-
      erated actuators, or electromechanically actuated mech-
      anisms are installed on valves to allow proper operation.
   Cover your ears dear... he is^
   closing the valve real fast, he |
    is sure to produce a bang!
                         *ซ*"* ซ        „
                         V*      C
                         .' f -
                         /*•. *•
In newer installations, it is common to use automatic
valves.  The valve types generally used in water distri-
bution systems include:  gate, butterfly, check, control,
pressure reducing, pressure relief, altitude, and air-and-
vacuum relief.  A brief overview and general function
of the most commonly used valves are presented in the
following sections.

3.5.1 Gate Valves
Gate valves are used to isolate distribution system sec-
tions. A sliding gate is moved up or down to block the
flow.  The purpose  of the valve  is to completely  stop
the flow and not to regulate it. These valves should not
be opened or closed too rapidly. Rapid valve operation
can cause a phenomenon known as "water hammer" or
pressure surge that  can  seriously damage distribution
system components. Water hammer is caused by the
sudden increase in pressure of water caused by the con-
version of the kinetic energy of the water in motion to
static energy when it is forced to stop. Under extreme
conditions, this pressure  surge may cause the pipes to
vibrate and/or create a hammering noise.   Figure 3.6
illustrates a gate valve.
Figure 3.6 Gate Valve (side view)

3.5.2 Butterfly Valves
A butterfly valve consists of a round disk attached to
a shaft in the pipe. Rotating the shaft by 90 degrees
(one quarter turn) opens or closes the valve.   In the
open position, the disk is parallel to the flow of water.
These valves are commonly used for larger diameter
pipes.  Similar to gate valves, these valves should not
be opened or closed too rapidly in order to avoid water
hammer. Figure 3.7 illustrates a butterfly valve.

Flow •
Flow i
Figure 3.7 Butterfly Valve (top view)

     3.5.3 Check Valves
     Check valves are designed to allow flow in only one di-
     rection. One common application of this valve is on the
     discharge side of a pump to prevent backflow when it is
     shut down. A variety of devices (e.g., weights, springs,
     motors) are available to dampen the closing of valves to
     minimize water hammer. Figure 3.8 illustrates a swing
     check valve.

     3.5.4 Other Valves
     Control valves are used to regulate flow between a ful-
     ly opened and a fully closed position. Control valves
     are almost always equipped with some sort of actuator
     mechanism to provide ease of operation.

     There are many types of pressure regulating and flow
     control valves.  For  example, a pressure sustaining
     valve tries to maintain a constant upstream pressure,
     whereas a pressure reducing valve maintains a constant
     downstream pressure.  An altitude valve is a serf con-
     tained pressure regulating valve that is used to control
     the flow into a tank in order to prevent water overflow.
     These valves are balanced to use the line water pressure
     as the operating motive. For example, when the tank
     level rises to a specified upper limit, the valve closes to
     prevent any further flow from entering, thus eliminating
     overflow. When the flow trend reverses, the valve reo-
     pens. In some places, high- and low-level tank indica-
     tors are also used to control flow.

     Pressure relief valves are installed to relieve excessive
     internal pressures (such as surge pressures) in a hydro-
     pneumatic tank as the  excessive pressure may lead to

     Air and vacuum valves, commonly referred to as air
     release/vacuum breaker valves, are  used to remove

4ft ^

r 4ft
/ -^^™ Backflow
\ \
                                                 Figure 3.8 Swing Check Valve (side view)

                                                 air from system components.  For example, deep-well
                                                 pumps are equipped with air release valves to exhaust
                                                 large quantities of air very rapidly from a deep-well
                                                 pump column when a pump is started.

                                                 3.5.5 Common Problems, Troubleshooting and
                                                      Maintaining Valves
                                                 Valves in constant use have parts that wear out and re-
                                                 quire routine maintenance. In addition, valves that are
                                                 not used regularly may not function when the need
                                                 arises. Valves can stick (due to deposition or rust for-
                                                 mation and growth of biofilm on the operating sur-
                                                 face) and even break (weakened by corrosion) if ne-
                                                 glected. A valve exercise program is a necessary part
                                                 of water distribution system maintenance.
                                                    We have initiated a valve |
                                                      exercising program   J

                                                      \   1    "*
                                                In cases where there is a high-pressure drop through
                                                a valve, it can lead to a number of immediate prob-
                                                lems such as cavitation, flashing,  choked flow, high
                                                noise levels and vibration.  Over the longer term,
                                                it  degrades system efficiency and results  in higher
                                                pumping costs.

                    Additional Information
  A NDWC Tech Brief on valves can be obtained online
  from:    http://www.nesc.wvu.edu/ndwc/pdf/OT/TB/OT_
  AWWA - M44, Distribution Valves: Selection, Installation,
  Field Testing, and Maintenance, Second Edition, 2006
  AWWA -M49, Butterfly Valves: Torque, Head Loss, and
  Cavitation Analysis, First Edition, 2001
  AWWA - M51, Air-release, Air/Vacuum and Combination
  Air Valves, First Edition, 2001
      3.6  Distribution  System  Hydrants
      Two types of hydrants are used in a distribution system:
      flush hydrants and fire  hydrants.  Flush hydrants are
      generally installed in a pit and have nothing projecting
      above ground. These hydrants are placed at the end of
      lines to remove accumulated corrosion products from
      dead-ends.  Flush hydrants  should  also be installed
      throughout the system  to provide for periodic flush-
      ing to maintain high water quality.  Sometimes, flush
      hydrants are mistaken for fire hydrants. Fire hydrants
      are larger in size. Fire hydrants are classified into two
      basic categories: wet barrel and dry barrel.  Wet bar-
      rel hydrants are designed to be used only in areas of
      the country where the temperature never drops below
      freezing,  since  these units are always charged with
      water.  Dry barrel hydrants are predominantly used in
      the U.S., and designed to  automatically drain water
                                         Upper Standpipe
                                         or Barrel
 Ground Surface
               Main Valve
               Drain Valve
  Fire Hydrant History (Adapted from Rader, L. undated):
  In colonial America, cisterns were  used to store water
  for early fire fighting purposes.  Around the time of the
  American Revolution, several American communities had
  built water distribution systems. These early systems used
  wooden main lines that workers had built using bored-out
  logs.  The logs were fitted together and buried. When fire
  fighters needed water, they uncovered the wooden line and
  bored a hole in the pipe wall. They used the water that
  collected around the pipe for fighting the fire. After the
  fire was put out, a tapered wooden plug was  driven into
  the hole in the pipe wall and the location of the hole was
  marked with the "fireplug." Later, when cast iron became
  the material of choice for water lines, it became harder to
  bore the hole. However, water systems installed tees with
  wooden plugs at convenient locations and the wooden fire-
  plug continued for several more years. The hydrant's evo-
  lution included a  standpipe  that fire fighters shoved into
  the tee after they removed the fireplug.  It conveyed water
  above ground to a hose connection and a ball valve, and
  it finally made the wooden plug obsolete. This setup was
  the forerunner of the dry-barrel compression hydrant.  Cis-
  terns continued to be used even after the introduction of the
  hydrant in many cities. As late as 1861, the city of Louis-
  ville, Kentucky employed 124 cisterns but no fire hydrants.
  Cisterns are still used today for firefighting.
after the water is turned off.
dry barrel hydrant.
Figure 3.9 illustrates a
Figure 3.9 Dry Barrel Hydrant
3.6.1 Common Problems, Troubleshooting and
     Maintaining Hydrants
Hydrants should be opened and closed slowly to avoid
water hammer effect.  Dry barrel hydrants should al-
ways be fully opened because operation of the  drain
mechanism is linked to the main valve.  A partially
opened hydrant causes water to leak through the base
which can cause erosion around the base of the hydrant.
Dry barrel hydrants need a supply of air to drain prop-
erly.  Therefore, the caps should not be tightened until
the unit finishes draining. Hydrants should be inspect-
ed on a routine basis for operability and leaks.  Many
different brands and models are available in the U.S. It
is important that parts provided or recommended by the
manufacturer be used for servicing each unit.  Hydrant
                   Additional Information
                                                          A NDWC Tech Brief on how to begin a fire hydrant op-
                                                          eration and maintenance program can be obtained online
                                                          from:    http://www.nesc.wvu.edu/ndwc/pdf/OT/TB/OT_

repair requires specialized tools that are available from
the manufacturer; using other tools may result in unnec-
essary damage and lead to the early failure of the unit.

3.7 Water Meters and  Service
Water meters are generally considered to be the last con-
nection in the portion of the distribution system owned
by a utility before water is delivered to the customer.
They are extremely important because they measure the
customer's water usage and are the basis for billing cus-
tomers for money to  support the utility's operation.  In
larger utilities, wastewater charges are frequently based
on water meter readings. A service line carries water
from the main to the water meter and/or curb stop or to a
customer's building plumbing. Meters are generally the
property of the water utility, but there are wide differ-
ences across the country with regard to the ownership of
service lines. Residential or building plumbing is almost
always the property of the home or building owner.

3.7.1 Water Meters
A water meter is a device used to measure the volume
of water usage.  Water meters are used at the service line
inlet to a residential and commercial building in a PWS.
Water meters can also be used at the water source, well, or
throughout a water system to determine flow through that
portion of the system. Water meters in the U.S. typically
measure and display total usage in cubic feet, or U. S. gal-
lons on a mechanical or electronic register. Water meters
are also used to generally define ownership and responsi-
bility. For example, maintenance and repair of pipes on
the "street side" of the water meter is the responsibility of
the PWS, and the customer/property owner is responsible
for the maintenance and repair of pipes and plumbing on
the "customer side" of the water meter.

There are several types of water meters in common use.
Selection is based on different flow measurement meth-
ods, the type of end  user, the required flow rates, and
accuracy requirements. In U.S., standards for manufac-
turing of water meters are made by the American Water
Works Association. Positive Displacement (PD) meters
are most commonly used and are generally very accu-
rate at low to moderate flow rates typical of a residential
user and a small commercial user.  Common PD meters
are sized between 5/8 and 2 inches. Because these me-
ters rely on water flowing through the meter to "push"
the measuring element, they are generally not practical
in large commercial applications  requiring  high flow
rates or low pressure loss. See Section 6.2.1 for other
types of flow meters.

PD meters normally  have a built-in strainer to protect
the measuring element from rocks or other debris that
could stop or break the measuring element. PD meters
normally have bronze, brass or plastic bodies with in-
ternal measuring chambers made from molded plastics
and stainless steel. Most meters in a typical water dis-
tribution system are  designed for cold potable water
only. There are other water meters manufactured for
specific uses.  For example, hot water meters are de-
signed with special materials that can withstand higher
temperatures. Meters for reclaimed water have  special
lavender register covers to signify that the water is non-
potable and should not be used for drinking.

Water meters are generally owned, read, and maintained
by the PWS. In some cases, an owner of a mobile home
park, apartment complex or commercial building may
be billed by a utility on one meter, and the cost of the bill
is shared among the tenants. In these cases, the complex
owner may purchase private water meters to separately
track usage of each unit in what is called submetering.

3.7.2 Service Lines
A  service line carries water from the main to the water
meter and/or  curb stop.  A curb stop box refers to the
enclosure which houses a valve. In case of an emergen-
cy or service  disconnection, this valve is used to shut-
off water service to the individual customer.  Most curb
stop boxes are not boxes, but cast iron housings with
a pipe that extends to the ground level with a remov-
able cover. The valve is accessed with a special wrench
which  is slid down the pipe and turns the valve off and
on. A  meter stop is a valve placed on the street side of
the water meter to isolate the water meter for installa-
tion or maintenance.  Many codes require a  gate valve
on the customer side  of the meter to shut off water for
performing customer plumbing repairs.

3.7.3 Common Problems, Troubleshooting and
Water meters  are generally well built, and require mini-
mal maintenance if installed correctly. If a meter is in
need of repair, it will generally under-register rather than
over-register the customer's water use. Because they
are very accurate, they can be used to identify leaks in
a customer's plumbing. For example, if a customer re-
ports excess usage bill, the first step would be to  shutoff
all water use in the building and observe if the meter is
still moving. In case the meter registers usage, it is very
likely that the customer plumbing contains a leak. The
customer should be recommended to obtain the services
of a licensed plumber to isolate and correct the problem.
Even small leaks over time can result in significant wa-
ter loss and resulting cost to the customer.

The majority of water leaks  in a distribution  system
occur in service lines, service fittings, and connections
including ferrules, curb  stops, valves and meters.   In

      addition, customer's plumbing and service lines have
      longer residence  times, more  stagnation, lower flow
      conditions  and elevated  temperatures than normally
      found in distribution systems and can have a negative
      effect on the quality of water supplied to the customer.

      Therefore,  service lines and their fittings provide  the
      greatest potential for intrusion and subsequently  for
      outside contamination to enter the distribution system.
      Compared to the main water distribution systems, less
      is known about the types and causes of service-line fail-
      ures than for other components of the distribution sys-
      tem. Some possibilities include:

         •   Internal and external corrosion

         •   Poor installations such as improper backfilling
            techniques and materials

         •   Damage during handling

         •   Improper tapping

      Many times during landscaping of the home, the curb
      stop access is buried or damaged. The cover lid can also
      be damaged, allowing debris to block access to the valve.
      Locating and marking the curb stop on a customer's
      property line can save time and money during an emer-
      gency when water needs to be  shut off.  The  curb and
      meter stop valves  are not designed for frequent use and
      can be ruined in a short time if used very frequently.

      Because  of the wide variation in ownership service
      lines, it is difficult to identify the party that should take
      responsibility for their maintenance.  This lack of clear
      responsibility can complicate the extent to which serv-
      ice lines are inspected, replaced, and repaired.  In most
      cases, a drinking water utility only assumes responsibil-
      ity for the quality  of water delivered to the curb stop or
      water meter.  For the portion of the service line owned
      by customers, the responsibility and cost of repairs falls
      on the customer.
  Service Line/Water Meter Repair (NRC, 2006)
  A recent report published by the National Research Coun-
  cil of the National Academies highlighted the issue of serv-
  ice lines and residential plumbing and their contribution to
  the deterioration of water quality.  A waterborne disease
  outbreak that occurred in Cabool, Missouri, in the winter
  of 1989-1990 was partially attributed to the need to replace
  a large number of water meters in the distribution system at
  the same time as the sewage overflow occurred.  The town
  had a population of approximately 2,100 people. A total
  of 243 cases of E. coli O157:H7 was reported, with 32 hos-
  pitalizations and four deaths.  It was  the first documented
  waterborne outbreak of E. coli O157:H7 ever reported.
3.8  Distribution System Asset
Distribution systems typically represent a water utility's
largest capital investment. In order for a distribution sys-
tem to operate at peak performance,  its status must be
continuously assessed.  The Asset Management (AM)
concept has emerged as an important mechanism for
tracking and  evaluating distribution  system operation
and maintenance (O&M) needs. The key focus of as-
set management is to minimize the amount of money
necessary to own, operate, and maintain a distribution
system asset (e.g.,  pumps, pipes, hydrants, and tanks)
over its useful life.  One key feature of an AM system is
to track the installed life of a distribution system asset.

  Asset Management (NMEFC, 2007)
  In 2005, the New Mexico Environmental Finance  Center
  (NMEFC) conducted an AM study for the Arenas Valley
  water distribution system in New Mexico. The Arenas val-
  ley water system purchases finished water from Silver City.
  The primary distribution system assets included: relatively
  new PVC pipe installed  in the 1980's (approximately 20
  miles of pipe), approximately 430 service connections, 25
  hydrants and 100 valves.  When the  study was initiated, the
  utility was concerned that a substantial portion of the sys-
  tem's PVC pipe had degraded/failed and needed replace-
  ment.  During the process of developing a comprehensive
  AM database, a pipe break event map was created depict-
  ing the 26 breaks previously recorded. Figure 3.10 shows
  the pipe break event map, which indicates that the majority
  of the breaks were service-line leaks and two of the 26
  breaks were caused by a  service-line tap. This pipe break
  map allowed the utility board to see that these pipes were
  not degrading as originally  suspected, and therefore did
  not need replacement. Also, a better grasp on assets and
  Level Of Service requirements allowed the utility board to
  see that it was more valuable to install new pipe that would
  create some loops in the distribution system, improving
  both service and possibly water quality.
  Figure 3.10 Arenas Valley Pipe Inventory and Main
  Break Map

The missing fire hydrant serial number obtained from
your asset management database helped us catch the
     crooks trying to sell it on the Internet."
 The "expected useful lives" of distribution system com-
 ponents are theoretically known and depend upon con-
 struction material, location, and environmental condi-
 tions. For example, the expected useful life of distribution
 system components is as follows: pipes - 35 to 50 years;
 hydrants - 40 to 60 years; valves - 35 to 40 years; storage
 tanks - 30 to 60 years; pumps -  10 to 15 years. Though
 these are typical values for expected useful life, there are
 always exceptions and it is not unusual, for example, to
 find some 100-year old pipes that are still in good condi-
 tion.  Generally speaking, when a specific asset begins
 to exceed its "useful life," it needs to be inspected peri-
 odically and reevaluated for replacement. For example,
 if the average age of the hydrants is  documented as 50
 years in the AM database, it is likely that a majority of the
 hydrants are near the end of their useful lives and would
 need to be replaced fairly  soon or evaluated on a regular
 basis. Basically, a good AM system contains a compre-
 hensive equipment inventory, and is closely linked to the
 Level of Service (LOS) concept.  LOS  clearly  defines
 performance goals and can be periodically used to define
 where, when, and how resources must be expended. The
 LOS defines a utility's commitment to the customer and
 its goals must be measurable. For example, a water utility
 might define its LOS as follows:

    •  Main breaks will be repaired within 8 hours of
       initiation of repair 90 percent of the time.

    •  Regulatory water quality requirements will be
       met 100 percent of the time.

    •  Monthly water losses will be kept to less than
       15 percent.

    •  Customer complaints will be responded to
       within 24 hours.
These LOS requirements make it possible for a utility
to prioritize its O&M activities in order to meet these
goals.  For example, if monthly water losses average
greater than 20 percent, the utility would initiate some
type of water audit and leak detection program.

The heart of any utility AM system is a complete inven-
tory of the pipes, tanks, pumps and other facilities that
make up the distribution system, coupled with a system
for recording and tracking  the status of those  assets.
Historically, information on distribution system assets
has been kept  in the form of maps and paper records.
In recent years, many larger water utilities have moved
to computerized mapping and database management
systems. Commercial AM software packages are now
readily available.   However, most  small- to  medium-
sized water utilities continue  to use paper records as
the primary method for tracking assets.  In many cases,
electronic AM takes a backseat to other utility func-
tions such as electronic billing and electronic reporting
(which may be required by regulations). Expenditures
for commercial AM software packages  and their asso-
ciated labor costs are generally perceived as being too
expensive for most small- and medium-sized systems.
The resulting lack of effective tracking often results in
a delay or deferment of needed repair and maintenance
of distribution  systems.

An economical solution to AM inventory and record-
keeping is the use of general spreadsheet or database
management software typically available on most per-
sonal computers.   These systems  can be  augmented
by  mapping software (Geographic Information Sys-
tem [GIS]  or  Computer Aided Design and Drafting
[CADD]). As an alternative, a utility may continue to
use paper-based maps.

CADD and GIS are more advanced geographic-based
computer systems that allow the user to store, display
and analyze spatial data. Historically, CADD packages
have been used by engineers and draftsmen in the design
of facilities. GIS grew out of the planning and mapping
fields as a means of constructing maps and analyzing
spatial data. The two fields have moved closer together
in terms of concepts and software and both are used
today as a basis for designing, analyzing and displaying
water distribution systems.

Table 3.4 provides a listing of the popular low-cost
CADD and GIS mapping software.

3.9 Distribution System Modeling
Distribution systems are designed to provide custom-
ers with needed flow  at an acceptable  pressure level.
Some questions frequently asked regarding the design
and operation of a distribution system are as follows:

 Table 3.4  Listing of Low-cost CADD and GIS Application Software
CAD Mapping Software
Web site
Ease of Use
Virtual Drafter
Windows 95,
98, ME, NT,
2000 and XP
Basic -$149,
w/ Service
Contract $249
Pro Version
2000, XP and
Deluxe V1 4
Deluxe - Price
Varies from
Windows XP
and Vista,
GIS Mapping Software
Free (Open
2000, XP, Mac
10+, Linux
JUMP V1 .2
Vivid Solution
Free (Open
Windows 2000,
XP, Mac10+,
Map Window
Map Window
Open Source
Free (Open
Windows 95,
98, ME, NT,
2000 and XP
Forestry GIS
Forest Pal
Free; Version
of software is
frozen in time
Windows 95,
98, ME, NT,
2000 and XP
System V6.5
Manifold. Net
- $245/$295;
- $295/$345
Windows 95,
98, ME, NT,
2000, XP and
Tatuk GIS Editor
$350, Free
Viewer Available
Windows 95, 98,
ME, NT, 2000, XP
and Vista
         •   How is a distribution system designed and
            operated to satisfy the acceptable flow and
            pressure objectives?

         •   How can one determine the flow available to
            fight a fire in a particular neighborhood on a hot
            summer day?

         •   How can one determine the consequences
            of taking a tank out of operation to perform
            maintenance activities such as painting?

         •   If an extension to the water system is built to
            serve a new development, what will be the
            pressure and will there still be an acceptable
            chlorine residual in the water delivered to the
            new service area?

      Computerized network models  can assist in provid-
      ing answers to these questions. These models are also
      referred to as distribution  system models or hydrau-
      lic and water quality models. Computerized network
      models  perform calculations based on mathematical
      descriptions  of flow and pressure.  The basic formula-
      tion of these models dates back to the work of Profes-
      sor Hardy Cross in the 1930s.  Today, these models
      are packaged in an interactive graphical  format that
      makes the data entry and analysis of results relatively
      easy.  Figure 3.11 is a computer screen shot depicting
      the results of an analysis of the SmallWater distribution
      system using the EPANET software package (available
      from EPA). Color coding and arrows are  displayed in
      order to show flow magnitude and direction, and pres-
      sure at junctions.
A distribution system  is represented as a network
model of links and nodes.  Links represent pipes, while
nodes represent junctions, sources, tanks or reservoirs.
Valves and pumps  are represented as either nodes or
links depending on the  specific software package.  In
order to "build" a network model, the location and con-
nectivity between each network component must be
known. Additionally, the following basic information
is required for the various types of components:

   •  Pipe: length, diameter, roughness

   •  Junction:  elevation, water use

   •  Tank:  diameter or dimensions, elevations

   •  Reservoir:  water level
Figure 3.11 Screen-shot Showing the Results of an
Analysis for the SmallWater Distribution System

I need some fresh pictures for my portfolio, I  have
    a new hydraulic modeling gig coming up!
                      Tank Water Level
   •  Pump: head-discharge curve, intial status

   •  Valve: type, settings

 There are two types of hydraulic analyses that may be
 conducted using a drinking water distribution system
 network model: steady-state and extended period simu-
 lation (EPS).  In a steady-state analysis, all water de-
 mands and operations are treated as constant over time
 and a single solution is generated. Steady state analysis
 is useful for assessing a distribution system under a par-
 ticular set of circumstances. For example, a steady state
 model could be used to estimate the amount of water
 available to fight a fire and the resulting pressures in a
 particular neighborhood on a hot summer day.

 In the EPS mode, variations in demand, tank water lev-
 els and other operational conditions are simulated by a
 series of steady-state analyses that are linked together
 in order to represent the  changes in flows and pres-
 sures over time.  EPS can be used to investigate dis-
 tribution system operation, study the behavior of tanks
 and pumps, assess energy usage, and serve as the basis
 for water quality modeling. Figure 3.12 illustrates plots
 from an EPS model of SmallWater showing the varia-
 tion in tank water levels and flow in a water main over
 a 2-day period. EPS models are "built" starting with
 a steady-state model.  Additional information that is
 needed for an EPS model include: variation in water use
 (demands) over the course of a day, operating rules that
 describe how pumps and valves are operated and mini-
 mum and maximum allowable water levels for tanks.

 Water quality models  use the  output from hydraulic
 models in conjunction with additional inputs to pre-
 dict the temporal and spatial variability of a variety of
 constituents within a distribution system.  These con-
 stituents include:

   •  the  fraction of water originating from a
      particular source
                  12   16   20   24   28   32   36   40  44  48
                           Time (hours)
Figure 3.12 EPS Plots of Tank Water Levels and Flow in
a Water Main Over a 2-Day Period,
   •   the age of water (i.e., duration since leaving the
      treatment plant)

   •   the concentration of a non-reactive tracer
      compound either added to or removed from the
      system (e.g., fluoride or sodium)

   •   the concentration of a reactive compound
      including the concentration and loss rate
      of a secondary disinfectant (e.g., chlorine
      or chloramines) and the concentration and
      growth rate of disinfection by-products (e.g.,
      trihalomethanes [THMs])

EPANET was initially developed in 1993  as a distri-
bution system hydraulic-water quality model to sup-
port research efforts at the EPA. The development of
the EPANET software has also satisfied the need for
a comprehensive public sector hydraulic/water quality
distribution system model. It has been a key compo-
nent in providing the basis for water quality modeling
incorporated  into many commercial models and  has
been  used  by many utilities  throughout the country.
In addition to EPANET, there are several commercial
software packages that are widely used in the United
States and internationally. Many of these packages
are based on the EPANET  formulation and include
value-added components that increase the capability of
the software.  Table 3.5 provides a summary listing of
available commercial  software and a Web  link where
additional details may be obtained on specific features,
current versions, availability and pricing.

      Table 3.5 Available Hydraulic-Water Quality Network Modeling Software Packages
Network Modeling Software Company Website
SynerGEE Water
Wallingford Software
Univ.of Kentucky
Fisher-Ulrig Eng.
GLS Eng. Software
Bentley Systems
                 3.10  SmallWater,  USA-
                         Asset Management
                         Problem Scenario
      SmallWater has been experiencing a rapid turnover of
      operators.  Often, during these personnel changes, one
      operator has left before another is fully trained. Conse-
      quently, much of the on-duty operator's time has been
      spent in locating  seemingly  misplaced maintenance
      records. Repair problems seem  to be increasing. The
      utility's managers are  increasingly concerned that the
      loss of trained operators, personnel turnover and mis-
      placed records are jeopardizing  the utility's ability to
      meet long-term water quality goals, to develop an O&M
      plan, and to meet their overall LOS requirements.

      Issues to Consider
      SmallWater does not have an AM system in place. It has
      limited finances to purchase commercially available AM
      software and is limited in its ability to provide training
      to operators for developing an in-house AM system.

      In order to solve these problems, it is recommended that
      the  utility investigate the use of a  simple spreadsheet-
      or database-based AM system.  Prior to selecting an
      AM system to track inventory and event data, the utility
      staff should examine its needs and determine which AM
      system provides the best fit.  If utility personnel are not
      familiar with the use of spreadsheet or database man-
      agement software, there are many readily available re-
      sources that can help provide training. These resources
      include local software  specialists, community colleges,
      and vendors. Also, there are many books that can pro-
      vide a good overview of available software packages.
      Once data  are entered into  a spreadsheet or database
      management system, the data can be sorted or filtered
      and custom reports can be generated. To be  effective,
      this system should be  viewed as a means for efficient
      O&M, not merely a recordkeeping tool.

      The key to successful inventory and recordkeeping is
the identification of all distribution system assets and
assignment of a unique identifier to each separate asset
component.  Figure 3.13 shows the SmallWater distri-
bution system with each component color coded.  Each
component type is assigned a letter (or letters) and with-
in that component type, individual items are assigned a
unique number.  For example, T-2 refers to tank number
2 and P-30 refers to pipe number 30. Individual pipes
are categorized as continuous "runs" between junctions,
where pipe characteristics (diameter or material) may
(or may not) change at other important locations such as
a tank, pump or major water users.

For each component, additional information of interest
can be collected and stored in the database. For exam-
ple, the following information would likely be stored for
   •   Pipe number
   •   Street name
   •   Diameter
   •   Length
   •   Material
   •   Date installed or replaced

Other types of information could easily be stored. For
example, in addition to the components shown in Fig-
ure 3.13, inventory data on hydrants and isolation valves
could be kept. Figure 3.14 shows the location of hydrants
in parts of SmallWater and the accompanying Table  3.6
contains  useful hydrant  inventory information.  This
type of data could be useful and provide the basis for an
inventory of assets. It is usually referred to as static data
since it remains relatively constant over time.

Other data that can be collected and stored in a data base
include information on pipe breaks, valve  exercising,
hydrant flushing, hydrant flow tests, water quality events
such as "red  water,"  or  any other distribution system
events or activities of interest.  This type of O&M infor-
mation is especially useful for evaluating the perform-
ance of assets and making decisions on future repair and

      Table 3.6 Hydrant Inventory Information
HyNdr J5L Add- *""ฐ- Avai;agpm)Flow
202 Main St.
224 Main St.
248 Main St.
286 Main St.
140 Spring St.
110 Spring St.
78 Spring St.
95 Spring St.
112 Lincoln St.
82 Lincoln St.




              \  WELL-1
                                                        replacement programs.  Table 3.7 shows a portion of an
                                                        event table for SmallWater.

                                                        The inventory and event tables serve as a permanent re-
                                                        pository for information on all actions taken related to
                                                        the distribution system. Figure 3.15 presents an exam-
                                                        ple schema (structure) that can be used to design such
                                                        a system within a spreadsheet or database management
                                                        system. The solid boxes show the elements in the water
                                                        system. The dashed boxes refer to maintenance events
                                                        for various elements, and the dashed lines show the re-
                                                        lationship between the elements and the maintenance
                                                        events. This schema can be modified, based on the spe-
                                                        cific needs of the utility. Some types of information may
                                                        not be of immediate interest to some utilities and other
                                                        data may be added as needed.
Figure 3.13 Components in the SmallWater Distribution

Pipe ID 	
Year installed


• Pipe ID
; Date
! Action
! Active?

Pipe ID
Fire Flow
Year installed

IsolValve ID •
i Pipe ID
Turn direction
Year installed
Pump ID Tank ID Valve ID
Pump station Diameter Valve type
Pump name Height Setting
Manufacturer Max level Diameter
Design flow Min level Year installed
Design head Year installed
Year installed

	 Hydrant ID

; Date
! Maintenance

Figure 3.14 Hydrant locations in part of SmallWater
     Table 3.7 Event Table
Figure 3.15 Sample Asset Management Database
Design or Schema
Component Date of Event Type of Event Notes
Type y|J
Flow Test

Valve cannot be closed


                  Distribution System  Infrastructure
    ACROSS                                      DOWN
    3  The longest components of a distribution          1
       system infrastructure
    4  Abbreviation for a commonly used plastic pipe      2
       in U.S. water distribution systems
    7  Configuration of distribution system that           5
       provides a higher degree of reliability of
       service to customers in case a main break         6
       occurs                                      8
    9  Centrifugal pumps require this at startup
    10  Term for keeping an inventory of distribution
        system components
    11  Type of valve that allows flow in one direction
Mechanical device that moves water from
surface to elevated storage tanks
Types of pumps most commonly used in
distribution systems
Can be a "turn on" or a "turn off" for water
Provides a water connection for fire-fighters
Two letters of the NSF logo designating pipe
approved for potable water use
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   (9 'S9A|EA (g 'OAd
                                                                    'S9d|d (C '|e6nj!J)U9Q fe 'sdwnd ( I,
                                                                            :uo!in|os PJOMSSOJQ

 Chapter 4

 Drinking Water


 Drinking water regulations are designed primarily to
 protect public health. As discussed in Section 2.4, the
 Safe Drinking Water Act (SDWA) was passed by the
 U.S. Congress in 1974 to protect public health by regu-
 lating the Nation's drinking water supplies.  The 1974
 SDWA and its amendments established the following
 four key elements:

   •  a framework (including schedule and
      procedures) for developing drinking water

   •  drinking water standards designed to include
      health-based goals, known as Maximum
      Contaminant Level Goals (MCLGs)

   •  technically achievable enforceable standards
      known as Maximum Contaminant Levels (MCLs)

   •  use of treatment techniques (TTs) instead of the
      MCLs (as necessary)

 The SDWA works in conjunction with the Clean Water
 Act (CWA), which controls the discharge of pollutants
 into lakes, rivers and streams. The CWA regulations are
 designed to protect the source water, whereas SDWA
 regulations are designed to protect water quality sup-
 plied to the general public (consumer) by public water
 systems (PWSs).

 Even though  CWA and SDWA generally work in con-
 junction with each other, some conflicts may arise be-
 tween the two acts as they have separate and distinct
 measures of water quality. As mentioned previously, the
 CWA prescribes Total Maximum Daily Loads (TMDLs)
 for different pollutants based on the designated use of a
 water body, whereas the SDWA prescribes MCLs.
           Regulated by
Safe Drinking Water Act
Clean Water Act (EPA, 2002a)

The  1977 amendments  to the Federal Water Pollution
Control Amendments of 1972 are commonly known as the
CWA. The goal of the CWA is to eliminate the releases of
toxic amounts of pollutants into waters of the United States
(e.g., rivers, lakes, streams). The CWA established the fol-
lowing three major programs:

  •  National Pollutant Discharge Elimination System
     (NPDES) Program - A system for granting and
     regulating discharge permits which regulates both
     point (industrial) and non-point (agricultural)
     discharges into waters of the U.S.

  •  Total Maximum Daily Load (TMDL) Program - A
     TMDL is the sum of the allowable loads of a single
     pollutant from all contributing point and non-point
     sources to a water body (e.g., river, stream, lake).
     The TMDL calculation includes a margin of safety
     to ensure that the receiving water body can be used
     for the state-designated purposes (e.g., drinking
     water supply, swimming, fishing). The TMDL
     calculation also accounts for seasonal variation in
     water quality.

  •  State Water Pollution Control Revolving Fund
     - To assist municipalities in creating wastewater
     treatment plants that were capable of meeting the
     standards, the CWA established a system to provide
     federal financial assistance. Initially, funding was
     provided in the form of construction grants.  This
     mechanism was modified several times and later
     replaced by the State Water Pollution Control
     Revolving Fund in 1987.

In response to the CWA, EPA finalized effluent guidelines
that regulate water pollution from 56 industrial categories.
It also established pretreatment requirements for industrial
users contributing wastewater to Publicly Owned Treat-
ment Works. It is estimated that these EPA regulations are
responsible for preventing the discharge of nearly 700 bil-
lion pounds of pollutants each year.
                                         Regulated by;
                                         Clean Water Act

       From a compliance perspective, PWS operators who
       discharge wastewater and/or storm water (during con-
       struction activities) from their facilities need to ensure
       that the applicable requirements of CWA are met. How-
       ever, the focus of this reference guide is distribution
       system water quality;  therefore,  only SDWA-related
       regulations are discussed in this chapter.  A summary
       of the  evolution of federal drinking water regulations
       since the  passage of the 1974 SDWA is presented in
       Figure 4.1.

       The regulations presented in Figure 4.1 are designed to:
       control microbiological contamination, control chemi-
       cal/radioactive contamination, and establish procedural
       requirements for meeting MCLs.  The following three
       factors determine if a specific  regulation or rule applies
           to a utility's operations:

              •  classification and size of the utility

              •  type of source water used (e.g., surface water,
                 ground water, or ground water under the
                 influence of surface water)

              •  type of water treatment used by the utility (e.g.,
                 filtration, disinfection)

           Based on these factors, if it is determined that a particu-
           lar rule applies, the utility must then meet the sampling,
           monitoring,  reporting,  treatment,   and management
           practices as outlined in the regulation.  These applica-
           bility decisions are  typically made by  the  state regu-
           latory agencies.   Failure to  meet these requirements
                                                                          Bioterrorism Act
                                 Public Health Security and Bioterrorism Preparedness and Response Act of 2002
                                                                  enacted Jun 12, 2002 (PL 107-188)

                            Arsenic and Clarifications to Compliance and New Source Contaminant Monitoring
                                                                     promulgated Jan 22, 2001
  Safe Drinking Water Act, enacted 1974
                             Phase I Rule
                       promulgated July 8,1987

                   Total Trihalomethane Rule
                   promulgated Nov 29,1979
        Public Notification Rule
              promulgated May 4, 2000
Total Coliform Rule
promulgated Jun 29,1989

Surface Water Treatment Rule
promulgated Jun 29,1989

          Phase V Rule
          promulgated Jul 17,1992
                           Radon in
                   Drinking Water Rule
              scheduled for promulgation
       NIPDWR                        I
       National Interim Primary Drinking Water Regulations
       enacted between 1975 and 1976         I

                           86SDWAA -I
     Safe Drinking Water Act Amendments of 1986
                       enacted Jun 16,1986
       Lead and Copper Rule
       promulgated Jun 7, 1991

     -Phase II and  MB  Rule
       promulgated Jan 30 and Jul 1,
                                                    Information Collection Rule
                                   promulgated May 14,1996; effective Jun 18,1996

                                      Safe Drinking Water Act Amendments of 1996
                                                         enacted Aug 6,1996

                                            Interim Enhanced Surface Water Treatment Rule
                                                            promulgated Dec 16,1998

                                                     Stage 1 Disinfection By-Product Rule
                                                            promulgated Dec 16,1998

                                                   Consumer Confidence Rule
                                                            promulgated Aug 19,1998
     Ground Water Rule
promulgated Nov 8, 2006
                                       Stage 2 Disinfection
                                        I  'By-Product Rule
                                    promulgated Jan 4, 2006
       Figure 4.1  The Evolution of Federal
       Drinking Water Standards
       (Adapted from EPA, 2005a)
                                                    Long-Term 1 Enhanced Surface Water Treatment Rule
                                                                        promulgated Jan 14, 2002
               Long-Term 2 Enhanced Surface Water Treatment Rule
                                    promulgated Jan 6, 2006

constitutes a violation under the SDWA and can lead
to enforcement actions and penalties.  The following
sections present a summary of the key regulations that
apply to small- and medium-sized utilities.

4.1 Highlights  of 1974  SDWA and
     its Amendments
Between 1975 and 1976, EPA adopted a set of Na-
tional Interim Primary Drinking Water Regulations
(NIPDWR). The NIPDWR provided the basis for the
first national drinking water standards.  These stand-
ards included limits for ten inorganic chemicals, six
organic pesticides, turbidity and five radionuclides.
In addition, the NIPDWR established standards for
microbiological  contamination  based  on total col-
iform organisms. In order to ensure that the water
quality  supplied to the public met these standards,
the SDWA required  that utility  operators routinely
monitor drinking water by sampling and testing the
water entering the distribution system for most con-
taminants and in their distribution system for other
contaminants.  The SDWA also required utilities to
notify their customers if the  standards or sampling
requirements were not met.   State regulatory agen-
cies were given the primary enforcement responsibil-
ity ("primacy") over their water supply systems, pro-
vided the individual  State program met the national
criteria.  Furthermore, the  SDWA required EPA to
assume the enforcement responsibility in case a State
was unable or unwilling to do the job of enforcing the
national standards.

4.1.1 1986 Amendments to SDWA
In 1986, the SDWA was amended and the NIPDWR
standards were declared to be final.  In addition, the
1986 amendments required EPA to:

   •  regulate 83 contaminants within three years after

   •  regulate an additional 25 contaminants every
     three years

   •  mandate disinfection for all PWSs

   •  mandate filtration for surface water systems

   •  designate best available technology for each
     contaminant regulated

   •  allow for TT instead of MCL

The non-community  water systems were  subdivided
into transient and non-transient  systems. States with
primacy were required to  adopt these regulations and
begin enforcing them 18 months after they were pub-
lished by EPA.
4.1.2 1996 Amendments to SDWA
The SDWA was amended again in 1996 to address these
concerns and provide funds for PWS infrastructure and
state program  management.  The  1996 amendments
made the following changes to the SDWA:

   •   allowed EPA to establish a process for selecting
      contaminants to regulate based on scientific
      merit and eliminated the need to regulate an
      additional 25 contaminants every three years

   •   established the Drinking Water State Revolving
      Fund (DWSRF) to help PWSs finance the costs
      of drinking water infrastructure needs

   •   added an emphasis on source water protection
      and enhanced water system management

   •   allowed for flexibility of regulations and
      monitoring for small systems

   •   required EPA to conduct cost-benefit analyses of
      new regulations and analyze the likely effect of
      the regulations on the viability of the utility to
      implement them cost-effectively

   •   provided all systems additional time to come
      into  compliance, plus allowed up to two more
     years if capital improvements were required

   •   established consumer confidence reporting
  Hmm... maybe it's time for
   us to amend the SDWA!
4.1.3 Variances and Exemptions
Each drinking water regulation includes provisions for
states to issue variances and exemptions.  Affordabil-
ity-based variances are available for small-to-medium
systems (serving fewer than 10,000 people) that allow
utilities to deviate from MCL or TT requirements under

  The EPA Regulatory Process (EPA, 2003b)
  To continually increase the effectiveness of the multiple
  barrier approach and protect drinking water customers,
  EPA develops regulations as new scientific or health infor-
  mation becomes available.  Each new regulation strength-
  ens or adds a needed barrier at one or more stages of the
  water supply process. After an extensive review of scien-
  tific and health information, EPA works with stakeholders
  and concerned citizens to draft a proposed regulation. The
  proposed regulation is published for public comment. EPA
  considers all comments and revises the regulation, if ap-
  propriate. A final regulation is then published.  A listing
  and details on specific current and proposed standards can
  be found on the EPA website at: http://www.epa.gov/safe-

      certain conditions.   Exemptions are designed  to give
      utilities additional time to comply with the new regula-
      tions. To use these variances and exemptions, the utility
      must first prove that the requested variance or exemp-
      tion does not pose an unreasonable risk to public health
      as determined by EPA. Also, variances and exemptions
      are not allowed for meeting the regulatory requirements
      for controlling microbial contaminants.

      General Variance  A general variance from meeting an
      MCL requirement can be requested if the  utility cannot
      comply with the MCL because of the characteristics of the
      source water.  This variance is granted only if the utility
      has already installed the EPA-designated Best Available
      Technology (BAT) for treatment to remove the contami-
      nant for which the MCL is being exceeded. In addition,
      the variance should not result in an unreasonable risk
      to public health, and the state agency must prescribe a
      schedule for compliance when granting this variance.

      Small System Variances States can grant small-system
      variances to systems serving fewer than  3,300 people
      without EPA approval. However, they must get EPA
      concurrence for variances to systems serving between
      3,300 and 10,000 people. EPA needs to identify afford-
      able variance technology for each regulation based on
      affordability criteria. As of 2005, no such small-system
      variances have been granted because EPA has not identi-
      fied any affordable small-system variance technology.

      Exemptions States may exempt PWSs from an MCL
      or TT requirement if the following three conditions are

         • The utility is unable to comply because
           of compelling factors, which may include
           economic factors.

         • The exemption must not result in unreasonable
           risk to public health.
                        •	;             \
                         You don't think this could qualify
                          as an Affordable Small System
                             Variance Technology...
               .t__w~-..   •>,;^;f csry
                      !   Tj •oV." _
               '.-i.-ฃM71 J^ ^J  '
               •t'hMEII (
                                      •   *~-
   •   The system was in operation as of January 1,
      1989, or, if it was not, no reasonable alternative
      source of drinking water is available to the new

In summary, the  variances and exemptions are tempo-
rary. Only under an extreme condition should a utility
consider these as options.

4,2  Regulations to Control
      Microbial Contaminants
Disease-causing  microbial contaminants  such as fecal
coliform (e.g., E. coif), Giardia, and Cryptosporidium
are frequently found in surface waters  and  ground-
waters under the influence  of surface water.  Figure
4.2 shows microscopic photographs of  the  disease-
causing microorganisms E.  coli, Giardia, and Crypt-
osporidium.  Some of the major rules that are intended
              Dad, I  heard you talking about affordable virus
              removal technology. This tool is guaranteed to
               remove all viruses, and best of all it's free!

Figure 4.2  Disease-Causing Microorganisms - E. coli,
Giardia and Cryptosporidium (not to scale)

      to control these microbial contaminants include:

        •  Total Coliform Rule (TCR)

        •  Surface Water Treatment Rule (SWTR)

        •  Interim Enhanced SWTR (IESWTR)

        •  Long-term 1 Enhanced SWTR (LT1ESWTR)

        •  Filter Backwash Recycling Rule (FBRR)

        •  Long-term 2 Enhanced SWTR (LT2ESWTR)

        •  Ground Water Rule (GWR)

      Table 4.1 presents a summary overview of each of these
      regulations and its applicability to small- and medium-
      sized systems, along with the  associated monitoring,
      treatment,  and management  practice  requirements.
      The information presented in the table  is only meant
      to provide a general overview  of the regulation.  EPA
      has developed many regulation-specific  factsheets and
      guidance documents that are much more thorough and
      cover the nuances of each regulation.

      4.3  Regulations to Control
           Chemical Contaminants
      Some of the major rules under the SDWA that are in-
      tended to control chemical contaminants include:

        •  Arsenic Rule

        •  Lead and Copper Rule (LCR)

        •  Stage 1 Disinfectants/Disinfection Byproducts
           Rule (Stage 1 D/DBPR)

        •  Stage 2 Disinfectants/Disinfection Byproducts
           Rule (Stage 2 D/DBPR)

        •  Radionuclides Rule

        •  Radon Rule

      Table  4.2 presents  a summary overview of each of
      these regulations and its applicability to small- and me-
      dium-sized systems, along with the associated monitor-
      ing, treatment, and management practice requirements.
      The information presented in the table  is only meant
      to provide a general overview  of the regulation.  EPA
                   has developed many regulation-specific factsheets and
                   guidance documents that are much more thorough and
                   cover the nuances of each regulation.
Additional  Information
Regulatory Guidance
                     EPA has prepared many rule-specific guidance documents
                     for public use.  In addition, EPA has prepared the follow-
                     ing guides which are tailored for small system operators:

                       1. Small Systems Guide to Safe Drinking Water Act
                          Regulations: The First STEP to Providing Safe and
                          Reliable Drinking Water - One of the Simple Tools
                          for Effective Performance [STEP] Guide Series.

                       2. Complying with the Ground Water Rule: Small
                          Entity Compliance Guide - One of the Simple Tools
                          for Effective Performance (STEP) Guide Series.

                     These and the other rule-specific regulatory guidance doc-
                     uments can be downloaded for free from the EPA website
                     at: http://www.epa.gov
                   4.4  Public Notification and
                         Consumer Confidence Rules
                   Public notification is intended to ensure that consum-
                   ers will know if there is a problem with their drinking
                   water. PWSs must notify their customers if: the  level
                   of a contaminant in the water exceeds EPA/state drink-
                   ing water regulations; there is  a waterborne  disease
                   outbreak or any other situation that may pose a risk to
                   public health; the water system fails to test its water
                   as required; or the system has a variance or exemption
                   from the regulations.  Depending on the severity  (tier)
                   of the situation, PWSs have a time limit of 24 hours to
                   one year to notify their customers. The three EPA des-
                   ignated tiers are as follows:

                      1.  Tier 1, for MCL violations and situations  with
                         significant potential to have serious adverse
                         effects on human health as a result of short-term
                         exposure. Notice is required within 24 hours
                         of the violation. A consultation with the state
                         agency is also required within 24 hours.

                      2.  Tier 2, for other violations and situations with
                         potential to have serious, but not immediate,
                         adverse effects on human health. Notice is
                         required within 30 days, or as soon as possible,
                         with extension of up to three months for
                         resolved violations at the discretion of the state
                         or primacy agency.

Table 4.1 Summary of Regulations Designed to Control Microbial Contamination (Adapted from AWWA, 2006a)
 Rule/Applicability to Small-and-
        Medium Systems
 Total Coliform Rule - Applies to all
    Rule Overview/Objective
Conforms are abundant in the feces
of warm-blooded animals. In most
instances,  coliforms themselves
are not the cause of sickness, but
they  are easy to culture and  their
presence is  used to indicate that
other pathogenic  (disease-caus-
ing) organisms of fecal origin may
be present which can cause  seri-
ous illnesses.
   Related General Monitoring
Sampling is required.  The number
and frequency of samples is based
on population served  by the PWS
and results of the sanitary survey.
Repeat samples are required within
24 hours if a  positive total coliform
sample is found. Furthermore, the
positive samples must be analyzed
for ฃ co//  (a fecal coliform).  Cer-
tain strains of ฃ co// are known to
cause illness in  humans.
Related Treatment Requirements
The  rule does not mandate any
specific treatment.   However,  if
monitoring indicates the presence
of coliform, treatment  may need to
be added  or  modified as neces-
sary to resolve the issue.
 Related Management Practice
The  rule does not mandate any
specific  management  practices.
However,  management practices
may need to be adjusted to meet
the  problems  uncovered  during
 Surface  Water  Treatment  Rule
 -Applies to all PWSs that use sur-
 face water or ground water under
 the influence of surface water.
Disease-causing  microorganisms
such as G/ard/a and Leg/onella are
present in most surface  waters.
This rule  establishes  criteria for
determining  if both  filtration and
disinfection  are  required  for re-
moval of these organisms.
Unfiltered systems  need to moni-
tor turbidity every 4 hours (source
water), residual disinfectant con-
centration  continuously (finished
water), maintain distribution sys-
tem disinfectant residual, and  the
total coliform levels (source water)
1-3 times  per  week,  depending
upon the population served.
Filtered systems need to monitor
turbidity at least every 4 hours and
residual disinfectant concentration
continuously (finished water).
Systems  may avoid  filtration if
they have low coliform and tur-
bidity in  source  water and meet
other site-specific criteria.  Sys-
tems that do not meet this crite-
ria must  install filtration treatment
and  the  state  must  determine
that filtration in  combination with
disinfection achieves the desired
G/ard/a (99.9% removal) and virus
(99.99%  removal) removal/inacti-
vation efficiency.
Unfiltered systems are required to
meet source water quality criteria
and maintain a watershed control
program. They are also subject to
annual  inspection and watershed
control program evaluation.
 Interim  Enhanced  SWTR   and
 Long-term 1  Enhanced SWTR.
This regulation builds  upon  the
SWTR  to  address Cryptosporid-
ium - a microorganism  that can
spread due  to  contamination  of
water from human or animal feces
leading to severe diarrheal illness.
Continuous turbidity monitoring is
required for each conventional and
direct filtration process, with val-
ues recorded every 15 minutes.
States  are required  to  perform
sanitary surveys.
Combined filter effluent must be <
0.3 NTU for 95 percent of monthly
readings  and may at no time  ex-
ceed 1.0  NTU.
Systems   requiring  compliance
must establish disinfection profile
and benchmark.  Any changes to
disinfection practice must be  ap-
proved by the state.
 Long-term  2  Enhanced   SWTR
 -Applies to all PWSs that use sur-
 face water or ground water under
 the influence of surface water.
This regulation builds  upon  the
address Cryptospor/d/um - a  mi-
croorganism that can spread due
to  contamination  of  water from
human or animal feces  leading to
severe diarrheal illness.
Required to  initially monitor  ฃ
co// for a  year and if the  annual
mean concentration in the  source
water  exceeds  specified  levels,
Cryptospor/d/um   monitoring   is
Depending upon the  initial moni-
toring results, the PWS is further
classified into four "bins" (Bin 1  <
0.075 oocyst/L,  Bin 2 - between
0.075 and 1.0 oocyst/L,  Bin 3 -
between 1.0 and 3.0 oocyst/L, and
Bin 4 > 3.0 oocyst/L).  Each bin
(except Bin 1) requires the PWS  to
install a treatment technology and
establish  a  monitoring schedule
based on contamination levels  in
the source water.  The treatment
options  range   from  improving
watershed control, reducing influ-
ent concentrations and additional
pre-treatment to  membranes and
advanced oxidation.
The  rule does not mandate any
specific  management  practices.
However,  management practices
may need to be adjusted to meet
the  problems  uncovered  during
 Filter  Backwash  Recycling Rule
 -Applies to all PWSs that use sur-
 face water or ground water under
 the influence  of surface  water; if
 they employ conventional or direct
 filtration, and recycle spent filter
 backwash  water,  thickener super-
 natant, and liquids from dewater-
 ing process.	
Spent filter backwash water, thick-
ener supernatant, and liquids from
dewatering  process  can  contain
microbial  organisms  such  as
Cryptospor/d/um.  This rule mini-
mizes the risks  associated  with
recycling these types of water.
The FBRR requires utilities to sub-
mit a  plant schematic  showing
recycle flow and plant flow to the
regulatory authority.   They  must
also retain any records on recycle
practices to document that the re-
cycling of the regulated streams is
performed correctly.
The recycle streams must be sent
to  a point  where they will pass
through all  the treatment process
steps before  entering the distri-
bution  system.  The  PWSs can
request approval for an  alternate
The  rule does not mandate any
specific  management  practices.
However,  management practices
may need to be adjusted to meet
requirements of the regulation.
 Ground Water Rule -Applies to all
 PWSs that use ground water.
This rule is designed to protect the
consumers  of ground water from
bacteria and viruses. It also seeks
to identify defects through sanitary
surveys in  water  systems  that
could  lead to contamination.
Systems  not achieving  mandated
level of microbial removal/inacti-
vation must, after a positive  total
coliform  result,  take  a  source
water sample and conduct further
tests (e.g., forฃ co//, enterococci,
orcoliphage). States also conduct
hydro-geological  assessments  to
identify if a particular  source  is
sensitive  to such  contamination
in  which  case  further monitoring
requirements are  applicable.
Systems that detect fecal contam-
ination would be required to take
corrective action that may include
disinfection,  removal of the con-
tamination source,  or  switching
The  rule does not mandate any
specific  management  practices.
However,  management practices
may need to be adjusted to meet
deficiencies noted in  the sanitary
survey requirements of the regula-
 aAII of the rules have recordkeeping and reporting requirements associated with the monitoring, treatment and/or management requirements.

Table 4.2 Summary of Regulations Designed to Control Chemical Contamination  (Adapted from AWWA, 2006a)
   Rule/Applicability to
 Arsenic Rule - the revised
 rule is called -Arsenic and
 Clarifications  to   Compli-
 ance and New Source Con-
 taminants Monitoring Rule.
 All CWSs and NTNCWSs.
          Rule Overview/Objective
The revised Arsenic Rule reduced the MCL from
0.05 mg/L to 0.01 mg/L.  Arsenic is shown to
cause cancer and other health effects.
      Related General Monitoring
The  rule makes monitoring  requirements
of arsenic consistent with those for other
inorganic compounds (lOCs)  regulated un-
der the standardized monitoring framework
Related Treatment Requirements
The rule  specifically lists  BATs and
small  system compliance  technolo-
gies (SSCTs).  The SSCTs including
Point-of-Use  (POU)/Point  of  Entry
(POE) technologies most likely to be
used by small systems include: acti-
vated  alumina treatment, reverse os-
mosis, and modified lime softening.
 Related Management
Practice Requirements'1
The rule does not mandate
any specific management
practices.   However, sys-
tems employing treatment
for the first time to meet
the  MCL  need to focus
and  develop  appropriate
technical,  managerial and
financial capacity.   Sys-
tems employing POU/POE
systems   must  maintain
excellent  customer rela-
 Lead and Copper Rule - All
 CWSs and NTNCWSs.
This rule establishes a 90th percentile action level
for lead at 15 micrograms/L (/jg/L) from the 50
jug/L previous level and copper action level of 1.3
mg/L. Lead is a toxic metal that can cause a range
of health effects including learning disabilities in
children. Long-term (more than 14 days) expo-
sure to copper in  drinking water at levels higher
than 1.3 mg/L  may cause kidney and liver dam-
age in infants.
The number of samples required (ranging
between 5 and 60 for small- and medium-
sized systems) depends upon the  system
size. Sampling frequency is annual, every
3 years, or every 9 years (depending upon
the  system size  and previous  monitoring
results).  If lead  or copper concentrations
exceed the specified action levels in  more
than 10%  of customer  taps sampled, the
PWS must undertake a number of additional
actions to control corrosion.
Corrosion  control treatment  is  re-
quired  unless  the  monitoring data
indicates levels  below the  action
level for two consecutive  6-month
sampling periods.    Source  water
monitoring  and treatment  may  be
required if the  action levels are ex-
ceeded  because of  elevated  levels
in source water.  If the service lines
are the cause of the exceedance and
the problem is  not corrected by cor-
rosion control,  service lines must be
The rule does not mandate
any specific management
practices.  However, man-
agement  practices  may
need  to be adjusted  to
meet the problems uncov-
ered during monitoring.
 Stage 1 Disinfectants/ Dis-
 infection  By-products  (D/
 DBPs) Rule-All CWSs and
 NTNCWSs that add chemi-
 cal  disinfectant to  water
 during the treatment proc-
 ess.  Certain requirements
 apply to TNCWSs that use
 chlorine dioxide.3
DBPs result from  a  reaction between the disin-
fectant (such as chlorine) and  the organic  and
inorganic compounds present in water.  The  rule
sets MCLs for haloacetic acid 5  (HAAS)  at 0.060
mg/L, chlorite (chlorine dioxide by product) at 1.0
mg/L, bromate (ozone byproduct) at 0.010 mg/L,
and total trihalomethanes (TTHMs) at 0.080 mg/L.
It also sets  maximum residual disinfectant levels
(MRDL) for chlorine (4.0 mg/L), chloramines  (4.0
mg/L) and chlorine dioxide (0.8 mg/L). DBPs can
potentially cause cancer and impact reproductive
health of humans.
For small and medium systems, 1  sample
per plant annually are required for THMs and
HAAs, generally in the warmest month, or
quarterly. Plants using ozone are required to
monitor monthly, and chlorine dioxide plants
are required to monitor daily at the entrance
to distribution system  and monthly within
the distribution system.  For systems using
conventional filtration, monthly sampling is
required for total organic carbon (TOG) and
alkalinity which are precursors that impact
the DBP formation.
Systems  that use surface water or
ground water under the influence of
surface water and employ conven-
tional filtration must remove a speci-
fied percentage (15 to  50%) of TOG
using either enhanced coagulation or
enhanced softening.  The specific %
requirement depends upon TOG con-
centration and alkalinity of  source
The rule does not mandate
any   specific    manage-
ment practices.  However,
management    practices
may need to be adjusted
to balance the  need  for
disinfection while minimiz-
ing  the  potential for DBP
 Stage 2 D/DBPs Rule - All
 CWSs and NTNCWSs that
 add chemical  disinfectant
 (other than  UV  light)  to
 water during  the treatment
 process  or  deliver water
 that has been disinfected.3
The rule builds upon the Stage 1  D/DBP Rule. The
covered PWSs are  required to perform an initial
distribution system evaluation  (IDSE) to identify
monitoring locations for eventual compliance with
the current standards for TTHM and HAAS.  Very
small systems (serving fewer than 500 people)
may seek waiver from IDSE.  The other option
is  to  obtain a "40/30" certification.   The  term
"40/30" refers to a system that under the Stage
1 D/DBP monitoring shows all samples  <, 0.040
mg/L for TTHMs and 0.030 mg/L for HAAS.
The  IDSE  determines the monitoring  site
locations.  The frequency of monitoring  is
based on both source water type and sys-
tem  size.  Generally, for small to medium
systems it is 2 samples per quarter or year.
Changes  in  treatment may be  re-
quired to remove the  DBP precur-
sor (TOG) for the reduction of DBP
concentrations.    Systems  should
explore operational changes, distri-
bution  system  modifications,  and
alternative disinfection  strategies as
The rule does not mandate
any   specific    manage-
ment practices.  However,
management    practices
may need to be adjusted
to balance the  need  for
disinfection while minimiz-
ing  the  potential for DBP
 Radionuclides Rule  - All
This rule builds upon the MCLs for combined ra-
dium-226/228 of 5 pico curies/liter (pCi/L), gross
alpha particle activity 15 pCi/L, and beta particle
and photon activity of 4 milliremt/year.  It adds a
uranium  MCL of 30 pg/L.  These radionuclides
are known to cause cancer and death at elevated
levels of exposure.
Monitoring of the  radionuclides other than
beta particle and photon emitters is consist-
ent with the SMFt.  Monitoring is required
at each  entry point to the distribution sys-
tem. Monitoring of beta particle and photon
emitters is not required for most CWSs.  If
the system is  designated by the state as
"vulnerable"  or "contaminated,"  monitor-
ing of beta particle and photon emitters  is
The small system compliance tech-
nologies  listed in the  rule are green
sand filtration, co-precipitation with
barium sulfate, electrodialysis,  ac-
tivated  alumina and  ion  exchange
POU/POE devices.  Special consid-
eration for spent media or cartridge
disposal may  be required.
The rule does not mandate
any specific management
practices.  However, man-
agement  practices  may
need  to be adjusted  to
meet  requirements  of the
 a Stage 1  D/DBP Rule compliance is based on running annual average (RAA), monitoring is plant-based. Stage 2 D/DBP Rule compliance is based on locational running annual average (LRAA),
 monitoring is population-based.
 bAII of the rules have recordkeeping and reporting requirements associated with the monitoring, treatment and/or management requirements.
 t The Standardized Monitoring Framework (SMF) was finalized by EPA in 1991  to simplify and consolidate monitoring requirements across contaminant groups. The SMF increases public health
 protection by simplifying monitoring plans and synchronizing monitoring schedules leading to increased compliance with monitoring requirements. The SMF reduces the variability within monitoring
 requirements for chemical [inorganic compounds (lOCs), volatile organic compounds (VOCs), and Synthetic organic compounds (SOCs)] and radiological contaminants across system sizes and
 types. Monitoring for asbestos, fluoride, nitrate and nitrite are different from monitoring requirements for other lOCs because these chemicals have unusual characteristics. The SMF established a
 9-year "compliance cycle" composed of three 3-year "compliance periods."  Newly regulated contaminants will be subject to the SMF. During the initial monitoring period, the rule requires PWSs to
 sample four consecutive quarters for each contaminant at each entry point to the  distribution system. Depending upon the results, systems may be able reduce their monitoring frequency to annually
 or once every 3,6, or 9 years. The SMF allows states to waive all monitoring requirements for all contaminants except nitrate (MCL of 10 mg/L) and nitrite (MCL of 1  mg/L).
 t millirem is a  unit of radiation dose equivalent to one-thousandth of a rem.  Roentgen equivalent man (rem) - A unit used  to express different types of ionizing radiations on a common
 scale to indicate its relative biological effects. For beta and gamma radiations: Exposure to 1 Roentgen delivers a dose of 1 Rad, which is equivalent to 1 Rem.


           3.   Tier 3, for all other violations and situations not
               included in Tier 1 and Tier 2, such as monitoring
               and reporting violations. Notice is required
               within 12 months of the violation, and may be
               part of a single annual report, including, in some
               cases, the annual consumer confidence report
               (CCR) already required by EPA.

        EPA  sets  strict  requirements  on the  form, manner,
        content, and frequency of public  notices.   Figure  4.3
        contains a  sample public notice.  Public  notification
        is  provided in addition to the annual water  quality
        report (or  CCR),  which provides customers  with a
        more  complete picture of drinking water  quality and
        system operations for the preceding year.  The annual
        CCR informs  consumers what  is in their water, where
        it comes from, and  where they can obtain additional
                                    "Hi Stan.  Our contractor dropped his
                                   cell phone into the finished water tank.
                                      Is this a Tier 1, 2 or 3 violation?"
                          2) When the
                            occurred —
                          6) Actions -—
                            should take
                          3) Potential
                            effects ,,
                          7) What is
                            being done to
                            correct the
                          10) Required
        Tests Show Coliform Bacteria in [System] Water

 The Jonesville water system routinely monitors for coliform bacteria.
• During the month of July, 7 percent of our samples tested positive. .
 The standard is that no more than 5 percent of samples may test

 What should I do?

    You do not need to boil your water or take other corrective
    actions. However, if you have specific health concerns, consult
    your doctor.                                        ^/
    You do not need to use an alternate (e.g., bottled) water supply.

    People with severely compromised immune systems, infants, and •
    some elderly may be at increased risk. These people should seek
    advice about drinking water from their health care providers.
    General guidelines on ways to lessen the risk of infection  by
    microbes are available from EPA's Safe Drinking Water Hotline at

 What does this mean?

 This is not an emergency. If it had been, you would have been notified
 immediately. Coliform bacteria are generally not harmful themselves.
 Conforms are bacteria which are naturally present in the environment
 and are used as an indicator that other, potentially-harmful, bacteria
 may be present. Conforms were found in more samples than allowed
 and this was a warning of potential problems.

 Usually, conforms are a sign that there could be a problem with the
 system's treatment or distribution system (pipes). Whenever we detect
 coliform bacteria in any sample, we do follow-up testing to see if other
 bacteria of greater concern, such as fecal coliform or E. coli, are
 present We did not find any of these bacteria in our subsequent

 What was done?

 We took additional samples for coliform bacteria which all came back
 negative.  As an added precaution, we chlorinated and flushed the
 pipes in the distribution system to make sure bacteria were eliminated.
 This situation is now resolved. -4	
                                         For more information, or to learn more about protecting your drinking
                                         water please contact John Jones at 555-1212.-

                                         Please share this information with all the other people who drink this
                                         water, especially those who may not have received this notice directly
                                         (for example, people in apartments, nursing homes, schools, and
                                         businesses). You can do this by posting this notice in a public place or
                                         distributing copies by hand or mail.

                                         This is being sent by the Jonesville Water System.
                                                  State Water System ID#1234567. Date Distributed: 8/8/06
        Figure 4.3  Sample Public Notice (EPA, 2007c)
4) Should alternate
  /water supplies be
                                                                                                     5) The
                                                                                                    -^*** population
                                                                                                       at risk
  8) When the
    system will
 — return to
                                                             • 9) Phone
                                                                number for

Sanitary Surveys (EPA, 1999)
A sanitary survey is an on-site survey of the water source, fa-
cilities, equipment, operation, and maintenance of the PWS for
the purpose of evaluating the  adequacy of such source, facili-
ties, equipment, operation, and maintenance for producing and
distributing safe drinking water. They are used to prevent and
correct sanitary deficiencies and are indispensable for ensuring
the delivery of safe water on a sustainable basis. When conducted
properly and with appropriate follow-up, sanitary surveys fulfill
the following objectives:
  •   Reduce the risk of waterbome disease;
  •   Provide an opportunity to educate system operators;
  •   Identify systems needing technical or capacity
      development assistance; and
  •   Identify candidates for enforcement action.
Sanitary surveys have been a critical component of state drink-
ing water programs for decades. States regulatory agencies are
required to complete sanitary surveys for all surface water sys-
tems and systems using ground water under the direct influence of
surface water (GWUDI) on the following schedule:
System Type
Noncommunity water system
Community water system
Community water system with
outstanding performance based
on prior sanitary surveys
Minimum Frequency
Every 5 years
Every 3 years
Every 5 years
The recent ground water rule extends sanitary  survey require-
ments to ground water systems.  Sanitary surveys may also be re-
quired when compliance problems arise. The PWSs are required
to cooperate with their regulatory agency and provide supporting
information when requested by the agency. Sanitary surveys can
be very useful for small utilities and provide them outside assist-
ance to identify weaknesses in the system before they cause seri-
ous problems. They can also help the utility regain control and re-
solve current weaknesses and avoid repeat compliance problems.
Sanitary surveys help evaluate the following issues:
   •   The capability of the PWS to monitor and manage water
      quality data
   •   System management and operational weaknesses
   •   Regulatory compliance weaknesses
   •   The integrity of supply sources
   •   Treatment adequacy and operational weaknesses
   •   Potential impacts of pumping
   •   Integrity of storage facilities, and
   •   Distribution  system weaknesses
After the sanitary survey is completed, the inspector generally
provides a follow-up report addressed to the PWS manager or
chief operator. The purpose of the report is to  summarize any
problems that have been identified, as well as recommendations
for necessary improvements. The report generally discusses each
of the items listed above in detail and provides dates by which the
deficiencies (if any) should be corrected. Sanitary surveys can be
a preventive tool, helping water utilities address weaknesses.
      ]L  4.5  SmallWater,  USA -
       T        Regulatory Scenario
Problem #1 Scenario
As previously presented in Section 2.7, in the 1990s,
the well (ground water) supply in SmallWater became
inadequate. Therefore, an alternate  source was devel-
oped in the form of an interconnection to the surface
water supply from a larger system located to the south-
east. The well field was maintained as a supplemental
and emergency  supply.  What regulations would cur-
rently apply?

Issues to Consider

   1) Is the source considered a surface water source
      from a regulatory standpoint because it has
      switched supply from ground water wells to
      purchased surface water?

   2) If the ground water source is used for
      supplementing for peak summer demand, what
      compliance issues are raised?

   3) Since SmallWater is buying treated surface
      water from another source which is in
      compliance with all surface water source
      requirements, does SmallWater have any
      compliance requirements?

Regulatory Guidance
SmallWater  should first contact its  state (primacy)
regulatory  authority and present the  entire operating
scenario.  From a regulatory standpoint, SmallWater is
considered as the supplier to the customers who live in
the SmallWater service area. At the  point where the
bulk purchase takes place, it is  SmallWater's respon-
sibility to ensure that the water quality supplied to the
consumer meets the surface water requirements man-
dated by the SDWA.

If ground water is used as a supplement to meet summer
demand, the supplier has to comply with both ground
and surface water treatment requirements.  SmallWater
should consult the state regulatory agency to make sure
the mixed water supply meets all regulatory require-

Problem #2 Scenario
Last July,  one  of the three  required monthly routine
total coliform samples in SmallWater showed positive
results. This triggered a series of actions including no-
tification to the state,  additional testing, and public no-

      Issues to Consider

         1) What is the procedure to identify if
            contamination is isolated to the plumbing
            system of an individual building from where the
            routine sample was drawn, or if contamination
            was in the distribution system itself?

         2) What should be done if a repeat sample is total

         3) How is the overall monitoring schedule affected
            by this event?

      Regulatory Guidance
      In response to the notification of positive total coliform
      sample, SmallWater was required to take action within
      24 hours. This response includes  collection of a set of
      three repeat samples to assess the extent of the problem.
      For water systems that collect one or fewer samples per
      month, a fourth repeat sample is  required. One of the
      repeat samples must be collected from the original sam-
      ple tap, one within five service connections upstream,
      and  one  within five  service connections downstream.
      This pattern of repeat sampling helps to determine the
      extent of contamination and potential cause of the posi-
      tive  sample. If a repeat sample is total coliform-positive
      at the same service connection, but negative at upstream
      and  downstream service connections, the state  may in-
      vestigate to determine if it is appropriate to waive the
      total coliform-positive sample as being a plumbing sys-
      tem problem in the individual building.

      If any routine or repeat sample is total coliform-positive,
      the positive sample is tested either for the presence of
      fecal conforms orE. coli. The test is done automatically
      by the lab and does not require an additional sample. A
      potential urgent health risk exists if any sample, routine
      or repeat, tests positive for fecal coliform/E1. coli. When
      notified by the laboratory that one of the samples tested
      positive for fecal coliforms or E. coli, SmallWater was
      required to notify the state by the end of the day. This
      notification is required on or before the end of the next
      business day if the state office is closed. The occurrence
      of a positive routine and repeat sample in conjunction
      with a positive fecal or E.  coli sample creates an acute
      violation of the MCL. In addition to notifying the state,
      SmallWater is also required to notify the public within
      24 hours by television, radio, hand delivery, or other
      methods approved by the  state, and consider advising
      their customers to boil their water.
coliform-positive sample results, they are required to
notify the state by the end of the next business day and
to notify the public within 30 days by mail, hand deliv-
ered notices, or other methods approved by the state.

In the month following detection of total coliforms in
any routine or repeat sample, SmallWater is required to
collect five routine samples. If none  of these tests are
positive for the presence of total coliforms,  they may
resume collecting their usual three routine samples the
next month. A total coliform-positive sample is cause
for  concern. However, if a set of repeat samples that
month and five routine samples the next month are all
negative, and their other multiple barriers to contamina-
tion are adequate, SmallWater should have confidence
that their water is safe.

Beyond the strict requirements for responding to a posi-
tive coliform sample, SmallWater may also consider the
following progressive steps to avoid further problems.

  1.  The sample-tap and sample collection
      procedures should be examined and reviewed.
      Coliform bacteria can come from unclean
      faucets, biofilm in the premise plumbing, and
      poor sample collection and handling procedures
      such as sample bottles sitting in melted ice in a
      cooler. Sample collectors may need to take more
      care in the collection process and sample faucets
      may need to be repaired and sanitized.

  2.  Local water main conditions should be
      reviewed. If the water system is chlorinated,
      chlorine test results should be evaluated to
      ensure that there is adequate chlorine residual.
      Local main breaks, flushing, unusual flow
      reversals, valve and hydrant operations  can all
      stir up or dislodge coliforms from sediments or

  3.  Storage facilities that influence  the water
      provided to the sample location from which the
      positive coliform sample was taken should be
      checked for possible contamination.
      A less serious but still significant potential health risk
      exists if more than one sample (routine and/or repeat)
      in a month is total  coliform-positive. This creates a
      monthly MCL violation. When SmallWater is notified
      by their laboratory of the repeat or second routine total

                   Drinking Water Regulations
                           6   7
3 The action level for this compound is 15 |jg/L
  under the Lead and Copper Rule
4 A microbial contaminant that is used as a
  general indicator of the presence of other
  disease-causing organisms
6 Acronym for the regulation designed to control
  Cryptosporidium in drinking water
           1 Time period within which a notice is required
             to the regulatory agency in case of a Tier 1
           2 Term for special allowances by the regula-
             tors to exempt small systems from meeting
             the regulatory MCL or treatment technique
           5 Abbreviation for the act passed by congress
             to protect drinking water in 1974
           7 Acronym for the sum of four disinfection
             byproducts formed due to reaction of
             chlorine with naturally occurring organic
IAIH11 (Z '
                                               (9 'VAACS (9 'WJOJHOQ fc 'pes~\ fe 'SSOUEUEA fe 'sjnon K ( \,
                                                                       suounios P.IOMSSOJO


Chapter  5

Distribution System

Water Quality Issues

Drinking water exiting the water treatment plant enters
a distribution system which is a complex network of
pipes, tanks and reservoirs designed to deliver finished
water to consumers. Although water entering a distri-
bution system may  meet drinking water standards, the
quality of the transported water may degrade within
the distribution system before it reaches the consumer.
Some of these undesirable changes such as objection-
able taste, odor or color can often be detected imme-
diately, whereas other changes in quality  such as the
intrusion of dangerous pathogens may only be noticed
after a waterborne  disease outbreak.   Some of these
pathogens include Salmonella and E.  coli.  Therefore,
proper distribution system management is essential to
protect consumers from both aesthetic and public health
threats due to deteriorating water quality. The following
sections in this chapter discuss common water quality
issues faced by water utilities, including small- and me-
dium-sized systems. These issues include taste, odor,
and color; biofilm formation; disinfection and disinfec-
tion byproducts (DBFs); nitrification;  pH stability and
scale formation; and contamination events.

5.1  Taste, Odor,  and Color
In most cases, taste and odor do not pose a public health
threat, and color in water can stain household applianc-
es and plumbing fixtures.  These aesthetic problems can
result due to various factors including the following:
poor source water quality, inadequate treatment, initiat-
ing disinfection of well with iron or manganese, chang-
es in water quality in the distribution system, and exter-
nal contamination events.  The Safe Drinking Water Act
(SDWA) established National Secondary Drinking Wa-
ter Regulations (NSDWR or secondary standards) that
are non-enforceable guidelines regarding contaminants
that may cause cosmetic effects (such as skin or tooth
discoloration) or aesthetic effects (such as taste, odor,
or color) in drinking water. EPA recommends second-
ary standards for water systems,  but does not require
these  systems to comply.  However, states may choose
to adopt them as enforceable standards and may require
monitoring and reporting.

All customers want their water to look, taste and smell
good; therefore, the utility operator should investigate
customer complaints  and  try  to  resolve these issues.
When complaints are filed, as a first step, the utility op-
erator should try to identify if the water quality problem
has occurred in the customer's plumbing or is due to
poor source water quality or treatment and/or changes
in the distribution system that can be controlled by the
utility operator. If more than one customer has reported
similar problems, it is likely that the issue is related to
source water, inadequate treatment or distribution sys-
tem problems.  The following sections discuss typical
customer concerns, their most common causes and ba-
sic troubleshooting techniques.

5.1.1 Taste and Odor Problems
Petroleum, gasoline, turpentine, fuel or solvent odor
Generally, the source of these types of odors is external
contamination (e.g., leaking underground fuel storage
tanks).  Therefore, it is recommended that the utility
perform on-site investigations to isolate and remedi-
ate the problem. Contaminated soil or ground water
can enter a well or it can permeate through plastic pipe
buried in a contaminated area. Small systems that lack
resources and expertise for tackling this problem should
notify the state agency.

Sulfur or rotten egg odor These types of odors are
commonly caused by bacteria growing in a sink drain
or in a water heater in the customer's home.  In some
cases, the smell may be caused by naturally occurring
hydrogen sulfide. As a first step, it is recommended that
the utility ask the customer to collect a small amount of
water in a cup, step away from the  odor-causing sink,
swirl the water around inside the cup and smell it. If the
water has no odor, the likely source is bacteria in a sink
drain. If the water continues to have an odor, a possible
source is the customer's water heater. This problem can
occur 1) if the hot water has not been used for a long
time, 2) if the heater has been turned off for a while, or
I   Do you have anything that will mask a
   "rotten egg" smell in drinking water?

      3) if the thermostat on the heater is set too low. If the
      sink drain and the water heater have been eliminated as
      the potential source of the problem, additional investi-
      gations will be needed. Sulfur odors can also originate
      from unmaintained household water treatment devices
      and from stagnant plumbing.  Sulfur odors can appear
      in dead-end mains or through a  backflow event and
      the distribution system piping may require flushing to
      remove the odor-causing material.  If the problem is
      system-wide, additional water treatment (such as car-
      bon filtration)  prior to distribution may be necessary to
      eliminate organic compounds  in the source water that
      may be causing the problem.

      Moldy, musty, earthy, grassy or fishy odor These
      odors can also be caused by bacteria growing in a sink
      drain or stagnant water. As indicated in the previous
      section, the customer should be requested by the water
      utility to collect a small amount of water in a cup, step
      away from the tap, swirl the water around inside the
      container and  smell it.  If  the water has no odor, the
      likely cause is bacteria in the  sink drain. If the water
      continues to have an odor, the  source is most likely al-
      gal bloom in the main water. Although generally harm-
      less, it may result in abnormal odor at very low con-
      centrations. Temporarily, this problem can be alleviated
      by  flushing (running the faucet for several minutes).
      However, it is possible that the distribution system may
      require flushing to remove the odor-causing material.
      If an algal bloom in the surface water source  is deter-
      mined to be the cause, additional water treatment (such
      as ozonation or carbon filtration) prior to distribution
      may be necessary to eliminate the problem.

      Chlorine,  chemical or medicinal odor  These types
      of odors are usually caused by the presence of excess
      chlorine in the water. Chlorine odors can result from
      disinfection of new pipe installations or due to poor con-
      trol of chlorine residual. Chemical or  medicinal odors
      may occur due to the interaction of excess chlorine with
      organic matter present in source water or the distribu-
      tion system piping. If the organic matter in the source
      water is not a problem and there are no nearby custom-
      ers reporting similar problems, it is recommended that
      the customer contact a licensed plumber and have the
      building pipes cleaned or replaced. If organic matter in
      the source water is found to be causing the problem, ad-
      ditional water treatment (such as carbon filtration) prior
      to distribution may be necessary to resolve the issue.

      Salty taste This type of taste is usually caused by natu-
      rally occurring sodium, magnesium or potassium com-
      pounds that are present in a coastal area where sea water
      may be affecting the fresh water supply. Naturally occur-
      ring high levels of total dissolved solids (e.g., Colorado
      River water) can also cause this problem. A utility should
work with the state, and additional site investigation may
be required to isolate and remediate the problem.

Metallic taste Metallic tastes may be caused by met-
als, such as aluminum, zinc, iron, copper or manganese
that leaches from distribution system piping as corro-
sion byproducts, or arise from the source water, or a
residual  chemical contaminant from water treatment.
Possible  sources of these tastes are treatment process
chemicals (e.g., coagulants or corrosion inhibitors) or
the source water. The corrosive potential of the finished
water must be evaluated to determine if the distribution
system piping could be a source (see Section 5.5, pH
Stability  and Scale Formation, for additional details).
Appropriate sampling and analysis may be required to
isolate the  problem.  Once the  problem is identified,
corrective techniques can be applied which may include
modification of the treatment process.

5.1.2 Color Problems
Green or blue water Corrosion of copper plumbing will
frequently cause a bluish-green  stain on porcelain fix-
tures. The cause of this problem is generally in the cus-
tomer's piping or due to corrosive water supplied by the
utility. Copper corrosion can sometimes appear in new
building  plumbing.  Also,  backflow of carbon dioxide
or other corrosive chemicals can cause copper corrosion
in plumbing. The corrosive potential of water should be
checked and, if necessary, adjustments need to be made
during treatment such that the water supplied is not cor-
rosive. Phosphate is commonly added to reduce corro-
sion in the distribution system. If the water supplied by
the utility is not corrosive, the customer should contact a
licensed plumber and possibly have the residential pipes
replaced. A short-term acute exposure (above the maxi-
mum contaminant level (MCL) of 1.3 mg/L)  can cause
gastrointestinal distress.  Long-term acute exposure can
result in liver or kidney damage. People suffering from
Wilson's disease should consult their doctor if the cop-
per in their water exceeds the MCL.

Brown, red, orange or yellow water Rusty water can
cause brown, red, orange or yellow water due to cor-
roding galvanized iron, steel or cast iron pipes in build-
ing plumbing or in the distribution system pipes. Local
water main conditions (valve operating, flow reversals,
and flushing) can upset corroded iron mains and stir
up rust. While unpleasant and potentially damaging to
clothes and fixtures, iron in drinking water is not an im-
mediate human health concern. The SDWA has a (non-
enforceable) secondary standard of 0.3  mg/L for iron.
The corrosive potential of water should be checked by
the utility and, if necessary,  appropriate adjustments
should made during treatment. Phosphate addition and
pH adjustment are commonly used to reduce corrosion
in the distribution system.

                      I'm feeling a bit flushed...   |
                      I think it is more than just
                       iron rust contamination    J
Black or dark brown water Manganese or other pipe
sediment can cause a black or dark brown color but
generally  clears up without further action after the
sediment settles in the water main.  Flushing of cold
water faucets and toilets is recommended. Manganese
does not pose a threat to human health. The SDWA has
a (non-enforceable) secondary standard of 0.05 mg/L
for manganese.  The utility should investigate to deter-
mine if the household is located in an area with chronic
low-flow issues that could lead to pipe sediments and
deposits.  If the problem is caused by the presence of
manganese in source water, additional treatment pri-
or to distribution  may be required to resolve the

Milky white or cloudy water   En-
trapment of air bubbles can result
in milky or cloudy water.  The
customer  should  fill  a
glass with water and set it on
a flat surface.  If the water
starts to  clear  at the bot-
tom  of the glass  first, the
cloudy or white  appear-
ance is  a natural occur-
rence.   Presence of air
bubbles is not  a health
threat and should clear in
about five minutes. If the
water does not  become
clear, additional   studies
should be  conducted  to
isolate and remediate  the
problem.  Galvanized  pipe
(zinc coating)  or aluminum
oxide can also make the water
appear milky.

Figure 5.1 depicts a taste and odor
wheel that  can assist  t
5.2  Biofilm
Biofilm consists of microbial organisms that  attach
to the interior surfaces  (e.g., pipes,  tanks) of water
distribution system pipes and tanks. These organ-
isms excrete a slimy glue-like substance that allows
them  to adhere to the piping or other water distribu-
tion system components. Figure 5.2  shows a picture
of biofilm  growth inside a pipe.  Generally, biofilm
in distribution system piping contains various species
of bacteria: most commonly coliforms, heterotrophic
and nitrifying bacteria. However, biofilm can contain
fungi, algae, protozoa, dead cells, corrosion products.
organic, and inorganic matter.  Typically, biofilms are
benign and do not cause health problems. However,
in many cases, their excessive growth leads to various
types  of problems and requires control. For example.
biofilms can shield disease-causing  microorganisms
such  as mycobacteria,  aeromonads  and Legionella
from residual disinfectants.  In addition, biofilms can
allow the growth of bacteria to reach a level that in-
terferes with total  coliform compliance  testing  or
support the growth  of coliform organisms to a level
that jeopardizes  compliance with the total coliform
;ar .
i %
Figure 5.2 Bio film Growth Inside the Pipe

      monthly standard.   Furthermore, biofilms can also
      produce taste- and odor-causing compounds, especial-
      ly after initiation of disinfection, leading to consumer
      complaints. Therefore, it is important to understand
      the factors that promote biofilm growth and the opera-
      tional techniques that can be employed to minimize
      biofilm growth as discussed in the following  subsec-

      5.2.1 Factors Aiding Biofilm Growth
      Drinking water is not sterile.  Thus,  bacteria in water
      will form biofilm as water always has enough nutrients
      (carbon, nitrogen and phosphorous)  to allow  biofilm
      growth to occur.  However, the rate  of biofilm growth is
      influenced  by the finished water quality and other con-
      tributing factors such as disinfectant type, residual disin-
      fectant concentration, pipe material, system hydraulics,
      corrosion activity and distribution system maintenance
      practices. The basic process begins with the seeding of
      Just like the "fire triangle,"
        for the biofilm to grow it
      needs three key nutrients....
the microbial organism in the system and the growth
rate is a function of nutrient availability and other con-
tributing factors which are discussed in this section.

The overall composition of the biofilm in a distribu-
tion system depends upon the organisms  that initiate
the growth.  For example, water main construction and
repair activities  can create an opportunity for some
undesirable  organisms to enter the  system and act as
"seeds" for growth. Thereafter, the availability of nu-
trients in the finished water is a key factor in biofilm
growth. The key nutrient that impacts biofilm growth
is total organic carbon (TOC) in water.  Some research
has pointed to specific components of TOC, notably as-
similable organic carbon (AOC) and biodegradable or-
ganic carbon (BDOC), as the key factors in influencing
biofilm growth. However, there is still much uncertainty
associated with the biofilm growth process.

Biofilm growth is amplified by factors such  as flow,
high temperature, corrosion,  and low  residual disin-
fectant levels. In general, low flow conditions tend to
favor formation of biofilms. Higher temperatures favor
the development of biofilms and increase  the diversi-
ty of microorganisms present in the biofilm.  A rule-
of-thumb is that water temperature at or above 15ฐC
(~60ฐF) tends to  experience greater bacterial  activity.
Corroded pipes are more supportive of biofilm growth
than non-corroded pipes, because the corrosion deposits
and tubercles (blister-like growth of iron oxides) can act
as a shelter to the organisms to protect them from the
disinfectant. Most disinfectants are effective in control-
ling the organisms that comprise a biofilm provided that
it comes in contact with the organisms.  However, the
dead cells, extra cellular molecules, and other compo-
nents of a biofilm react with the disinfectant to limit
their destructive ability. The type of disinfectant used
can also affect biofilm growth.  In some instances, the
use of chloramines may yield better biofilm control.

5.2.2 Operational Factors Inhibiting the
     Growth of Biofilm
Biofilm growth in distribution system piping is inevi-
table, given that  small quantities of microorganisms
are always present in source water and pass  through
treatment or can be introduced accidentally during con-
struction and repair activities.  Operational techniques
can be implemented to inhibit biofilm growth by the
following: reducing available nutrients, optimizing dis-
infectant dosage, controlling  corrosion and periodic

Reducing nutrient availability As mentioned in the
previous section, TOC is usually the key nutrient that
impacts biofilm growth  in drinking  water systems.
Utilities should consider treatment techniques such as

enhanced coagulation and/or activated carbon nitration
in conjunction with source water protection measures
to reduce the overall TOC levels in water.  For some
utilities, another option is to move the point of disinfec-
tion (to a point after the filtration process).  This allows
bacteria to  grow in the filter media and consume the
biodegradable fraction  of TOC, even though the over-
all TOC levels are not  significantly reduced. In some
systems,  nitrogen may be the limiting nutrient factor.
Ammonia,  nitrate or nitrite removal technologies may
be employed by the operator to reduce nitrogen avail-
ability. For systems using chloramines, careful control
of ammonia addition may help to reduce residual free
ammonia in the finished water.

Optimizing disinfectant dosage Disinfectants can re-
duce the growth of biofilm in  a distribution system.
However,  residual disinfectant  must  be  available
throughout the distribution system. In many cases, it
may not be practical to maintain residual levels based
on  disinfection at one  central  location.   Distributed
booster chlorination stations may be more effective in
maintaining residual levels in areas of low-flow and
stagnation, especially during warmer water tempera-
ture months.
This automated antibiotic
drip system is designed to
     control Biofilm
Corrosion control As discussed previously, corrosion
deposits and tubercles can act as a shelter to help pro-
tect biofilm from a disinfectant.  In moderate to severe-
ly corroded iron pipes, the exposed surface may take up
a vast majority of the available disinfectant.  Proactive
corrosion control practices may result in better control
of biofilm growth. Water main rehabilitation or replace-
ment is another option.

Flushing Flushing at velocities greater than 2 feet/sec-
ond can physically remove some biofilm by scouring.
Flushing can also remove accumulated debris and cor-
rosion products that shield the  biofilm from disinfec-
tion. Flushing is only a temporary measure; the under-
lying conditions that support biofilm growth need to be
addressed simultaneously.

5.3  Disinfection and Disinfection
All utilities using surface water sources are required
by EPA to disinfect the water prior to delivery  to their
consumers.  The intent of this  requirement is  to pro-
vide a barrier against disease-causing microorganisms.
The process which destroys or removes disease-causing
organisms is termed "disinfection." Chlorine and chlo-
ramines are the most commonly used disinfectants in
the U.S.    Furthermore, it is necessary that a residual
disinfectant be maintained throughout the distribution
system. Loss of disinfectant residual is one of the most
common water quality concerns. The availability of a
disinfectant residual is a function of time and rate of de-
cay or loss caused by consumption of disinfectant at the
pipe wall and in the bulk water. Excess disinfectant lev-
els lead to  undesirable changes in water quality when
the disinfectants  react with naturally occurring  organic
matter or compounds, such as TOC or bromide, in the
source water/distribution system to form DBFs.
                                                                              I wonder if the new disinfectant
                                                                             soap we are using for handwashing
                                                                             causes any disinfectant byproducts
                                                                                  to form on our hands...

      Although studies are ongoing to determine the long-
      term health effects of exposure to DBFs, EPA has
      already set monitoring requirements  and MCLs for
      some of  the  more common DBFs  including: tri-
      halomethanes (THMs),  haloacetic  acids (HAAs),
      bromate,  and chlorite.  If DBFs are a problem, the
      utility  should carefully  evaluate the key variables
      that impact their formation including: residual dis-
      infectant levels, water age in the distribution system,
      TOC concentration, pH, and water temperature.   A
      DBF problem scenario is described in Section 5.7  at
      the end of this chapter.

      5.4 Nitrification
      Nitrification in drinking water distribution systems  is
      the transformation of ammonia to nitrate. In this proc-
      ess, ammonia is first transformed to nitrite by bacteria
      and subsequently, nitrite is transformed to nitrate as a
      bacteriological process or simply in the presence  of
      oxygen.  Nitrifying bacteria are slow-growing organ-
      isms, and nitrification problems usually occur in large
      reservoirs or  low-flow  sections  of distribution sys-
      tems.  Ammonia is present in drinking water through
      either naturally-occurring processes or through the
      addition of ammonia during disinfection to form chlo-
      ramines. Given similar levels of TOC and temperature
      in the source water, chloramines form less DBFs than
      chlorine.  Therefore, chloramine use is expected to in-
      crease as a direct result of more stringent DBF MCLs
      associated with the Stage 1 and Stage 2 D/DBP Rules
      (see Chapter 4).
                          If you paid attention in your
                        chemistry class, you would know
                        they stand for nitrite and nitrate!
Nitrate and nitrite levels in water are required to be
monitored at the entrance to the distribution system.
If the levels  are greater than one-half of the MCL,
additional proactive monitoring  and troubleshooting
should be performed.  Nitrate and nitrite have direct
health implications. Nitrate is transformed to nitrite
in the human digestive  system.  The nitrite ion oxi-
dizes iron in the hemoglobin of the red blood cells to
form methemoglobin, which lacks the oxygen-carry-
ing ability of hemoglobin. This creates the condition
known as methemoglobinemia (commonly referred
to as "blue baby  syndrome"), in which blood lacks
the ability to carry sufficient oxygen to the individ-
ual body cells causing the veins and skin to  appear
blue. Infants under 6 months of age and older persons
with genetically impaired enzyme systems are unable
to reduce toxic methemoglobin to oxyhemoglobin.
Therefore, ingestion of nitrite and nitrate can be fatal
in these susceptible population groups. To protect the
susceptible population, EPA has mandated the MCL
for nitrate to be 10 mg/L (measured as nitrogen) and
1 mg/L for nitrite (measured as nitrogen).  Most indi-
viduals over one year of age have the ability to rapidly
convert methemoglobin back to oxyhemoglobin.

It is important to recognize that nitrate and nitrite may
come from sources other than nitrification.  It has been
found that 93 percent of all U.S. water supplies contain
less than 5 mg/1 nitrate, but these values may be chang-
ing as a result of the increased use of nitrate-contain-
ing fertilizers that enter  source waters.  Increased use
of chloramination may also result in higher levels of
nitrate in drinking waters because of partial nitrification
in the distribution system. The nitrification process in
a distribution system can be controlled by utility op-
erators by controlling the presence of ammonia, mini-
mizing the low-flow areas in distribution systems and
controlling the growth of biofilm that may contain the
nitrifying bacteria.

5.5 pH Stability and  Scale
It is important to maintain a stable pH as part of main-
taining distribution system water quality.  Excessive
changes in pH can lead to water quality problems. For
example, low pH values (less than 7.0) can accelerate
the internal corrosion of metallic pipes, and can lead
to leaching of lead and copper in pipes and plumbing
fixtures. Therefore, a  certain level of scaling  in me-
tallic pipes is helpful in passivating the pipe  by de-
positing a protective carbonate layer on it. However,
higher pH (greater than 9) can cause excessive scale
formation which can significantly reduce the carrying
capacity of a pipe and provide a shelter for biofilm
growth. Scales in pipes are formed due to the precipi-

    tation of mineral constituents in water onto the pipe
    walls. Scale formation is a complicated process that
    depends on a variety of system-specific physical and
    chemical conditions and pH is only one of the factors.
    Scale-forming potential is often measured by the Cal-
    cium Carbonate Precipitation Potential or the Lange-
    lier Saturation Index (LSI).
Langelier Saturation Index (LSI) (CD, undated)
In order to  calculate the LSI, it is necessary to know the
alkalinity (mg/1 as calcium carbonate [CaCO3]), the cal-
cium hardness (mg/1 Ca2+ as CaCO3), the total dissolved
solids (mg/1), the actual pH, and the temperature of the
water (ฐC).

LSI = pH-pHs

Where: pH  is the measured water pH and pHs is the pH at
saturation in calcite or calcium carbonate and is defined as:
pHs = (9.3+A + B)-(C + D)

A = (Log10  [total dissolved solids] - 1) /10
B = -13.12  x Log10 (ฐC + 273) + 34.55
C = Log10 [Ca2+ as CaCO3] - 0.4
D = Log10 [alkalinity as CaCO3]

A negative LSI value indicates that there is no potential for
scaling to occur, the water will dissolve CaCO3. A positive
LSI indicates that scaling can result from CaCO3 precipita-
tion. An LSI close to zero is the desirable in most cases.
     5.6  Contamination  Events
     Drinking water distribution systems are vulnerable to
     external contamination from cross-connections, perme-
     ation/leaching, intrusion/infiltration and reservoir/stor-
     age facility contamination. These problems are briefly
     discussed below.

     5.6.1 Cross-connections and Backflow
     Almost all distribution systems  contain  locations
     where accidental  cross-connections  between  pota-
     ble drinking water and  non-potable water can occur.
     These cross-connections can provide a pathway  for
     backflow  of non-potable water (i.e., contaminated
     water into potable supplies). Backflow occurs either
     because of reduced pressure  in the distribution system
     (termed backsiphonage) or due to the presence of in-
     creased pressure from a non-potable  source (termed
     backpressure). Backsiphonage may be caused by a va-
     riety  of circumstances, such as main breaks, flushing,
     pump failure, hilly terrain, limited pumping capacity,
     high demand by consumers,  or emergency firefighting
     water drawdown.  Backpressure can occur when heat-
     ing/cooling, waste disposal,  or industrial manufactur-
     The extensive scaling has reduced
    the pipe diameter to 20% of design
    capacity. If we adjusted the pH and
    cleaned the pipes, we could meet the
      new demand in this service area.
ing systems are connected to potable supplies and the
pressure in these external systems exceeds the pres-
sure in the distribution system.  In both cases, the di-
rection of water flow is reversed, causing non-potable
and  potentially contaminated water from industrial,
commercial, or residential sites to flow back into the
distribution system through a cross-connection.

The  risk posed by cross-connection and backflow can
be minimized.  For example, it can be prevented by
installing backflow prevention devices and assemblies
and  through formal  programs to seek out and cor-
rect  cross-connections within the distribution system.
Some water systems  have programs to identify cross-
connections or the  potential  for cross-connections
in individual service connections.  Some corrective
measures include activities such as flushing and clean-
ing a distribution system after an incident.

There is no easy way to detect and monitor for the oc-
currence of cross-connection and backflow. Also, there
are no national reporting requirements for backflow in-
cidents, and no central repository exists for backflow
incident  information. Some states have detailed re-
quirements and other states have minimal requirements
for cross-connection  control. The number of reported
incidents is believed to be a small percentage of the to-
tal number of backflow incidents that actually occur in
the U.  S.  There is a lack of general awareness about
the threat posed by  cross-connections and backflow
through illegal and unprotected taps.  PWS operators
should be aware that there is a potential for intentional
contamination  of a distribution system through such

      5.6.2 Permeation and Leaching
      Permeation of piping materials and non-metallic joints
      is denned as the passage of contaminants external to
      the pipe, through porous, non-metallic materials, into
      the drinking water and is generally limited to plastic
      and other non-metallic materials. Volatile organic com-
      pounds present in the ground can permeate plastic pip-
      ing and gaskets.

      Leaching is denned as the dissolution of metals, solids,
      and chemicals into drinking water.  Leaching from ce-
      ment linings can occur in soft, aggressive, poorly buff-
      ered waters. Under static conditions, metals such as alu-
      minum, arsenic, barium, chromium, and cadmium can
      leach from cement linings, even when NSF-approved
      materials are used and  linings are applied according to
      AWWA standards. Vinyl chloride can leach from PVC
      pipe manufactured prior to 1977.  The SDWA has estab-
      lished an MCL of 0.002 mg/L (2 ug/L) for vinyl chloride;
      however, no instances of MCL violations have been cited
      in connection with PVC pipe manufactured after 1977.

      Permeated plastic piping must be replaced since the
      piping retains its swollen porous state after permea-
      tion. Operators of small PWSs using non-metallic pipes
      should be aware of permeation and leaching problems
      and address them appropriately. Operators should avoid
      placing plastic pipes (mains or service lines) in soils
      and ground water environments  that may be contami-
      nated with organic solvents and petroleum products.

      5.6.3 Intrusion and Infiltration
      A pressure transient in a drinking water pipeline caused
      by an abrupt change in the velocity or direction of water
      can cause a surge or "water hammer."  When a valve
      is closed rapidly, it suddenly  stops water flowing in a
      pipeline  and the  associated pressure energy is  trans-
      ferred to the valve and pipe wall.  Similar action can
      occur when a pump is  shut off rapidly,  as may happen
      with a power outage. Shock waves circulate within the
      distribution system and pressure waves sometimes pro-
      duce a banging noise as it travels back and forth.  A less
      severe form of water hammer is called a surge where
      a slow motion mass oscillation of water is caused by
      internal pressure fluctuations  in the  system.  If these
      pressure transients are not controlled, they can damage
      pipes, fittings,  and valves, causing leaks and shortening
      the life of the  system. The production of this transient
      low- and negative-pressure creates the opportunity for
      contaminated water to intrude  and infiltrate the pipe
      from outside. Such pressure transients can back-siphon
      environmental water in soil (or flooded valve and meter
      pits) into the mains through leaking joints or cracks.

      5.6.4 Storage Facility Contamination
      Reservoirs and neglected finished water storage  facili-
ties such as reservoirs and tanks can be a dangerous
source of contamination.  When unchecked, animals,
birds  and pests can inhabit and contaminate these fa-
cilities.  If these facilities are improperly maintained,
they can quickly spread the contamination throughout
a distribution system. Storage facilities should be thor-
oughly inspected on a regular basis.
                                  Looks like we have
                                   a storage facility
                                contamination problem!
  Storage Tank Contamination (Clark et al, 1996)
  In December 1993, a Salmonella outbreak was identified in
  the Gideon, Missouri, municipal water system.  This out-
  break affected around 486 of the 1,104 residents and caused
  seven deaths among nursing home residents. Ensuing EPA
  investigations supported by other federal, state and local au-
  thorities concluded that all the affected residents had con-
  sumed municipal water. The investigations revealed that a
  large municipal storage tank was in a state of disrepair with
  bird parts and other floating debris which was determined
  to be the source of contamination. During November 1993,
  the residents of Gideon reported objectionable tastes and
  odors in the drinking water supply. The utility superintend-
  ent  initiated an  aggressive and comprehensive flushing
  program and flushed the hydrants in the system. Unfortu-
  nately, the flushing program resulted in water being drawn
  from the municipal tank that was severely contaminated
  with Salmonella which dispersed throughout the network.
  This preventive  action led to a major waterborne disease
  outbreak. Initially, it was suspected that the sediments in
  the tank owned by the private company also connected to
  the distribution system and was the source of the outbreak.
  However, a pressure test confirmed that the backflow pre-
  vention  valve connecting the private  tank to the  Gideon
  network was functioning properly.  A modeling analysis
  confirmed that the earliest reported cases of disease were
  found to be from areas receiving water predominantly from
  the contaminated municipal tank.

                 Additional  Information
                 Taste,  Odor, Flushing, DBF,
                 Nitrification and Cross-
NESC. Tech Brief: Taste and Odor Control. 2006.
AWWA. Water Supply Operations: Flushing and Cleaning
- DVD. 2006.
AWWA. Cost and Benefit Analysis of Flushing. 2004.
EPA. Technologies and Costs for Control of Disinfection
By-Products. October, 1998
EPA. Nitrification. August 15, 2002.
EPA. Cross-Connection Control Manual. February, 2003.
          |L  5.7 SmallWater, USA -
           7        Water Quality Problem
    Problem #1 DBF Scenario
    SmallWater purchases water from another supplier and
    has discovered a compliance problem with DBFs (par-
    ticularly THMs and HAAs) in its purchased water.  The
    supplier chlorinates the water and the long travel time to
    SmallWater and within the SmallWater distribution sys-
    tem frequently leads to the formation of excess DBFs.

    Issues to Consider
    Elevated DBF  levels can be a difficult problem to al-
    leviate.  This is especially true in this situation where
    SmallWater purchases most of its water from another
    utility and has little control over the source water and
    treatment process. Issues that should be considered in-

       •   Does the water comply with DBF levels in the
          new Stage 2 DBF Rule?

       •   If it is not in compliance, what are the primary
          causes for the elevated DBF levels? Potential
          problems could be high levels of DBF
          precursors in the source water coupled with
          insufficient or incorrect treatment, long travel
          times for the finished water to reach the town,
          and/or excessive travel times from the entry
          points into the town until the water reaches the
          town's customers.

    Regulatory Guidance
    The initial question that SmallWater should address is
    whether or not the elevated DBF levels are due prima-
    rily to the characteristics of the source water and treat-
    ment. Another question is whether or not excessive wa-
ter age has led to high levels of DBF formation during
the time when the water is traveling to SmallWater and
within the SmallWater distribution system.

Sampling data showed that THM levels at the point of
entry to the town were in compliance and typically av-
eraged around 40 to 50 ug/L while samples within the
SmallWater distribution system frequently exceeded 80
ug/L and, in some cases, exceeded 100 ug/L. This sug-
gested that THM formation within the town was the pri-
mary cause of the elevated DBF levels. A quick calcula-
tion of the travel time for the water from the treatment
plant to the town for the purchased water showed that,
under average conditions, it took about 20 hours. This
was compared to the map of maximum water age (from
the entry points to the town) that the town's consultants
produced from their hydraulic model.

Figure 5.3 indicates that maximum travel times within
the town were typically in the range of 1 to 5 days. This
far exceeded the 20-hour travel time for the purchased
water to reach the town. Both the sampling data and
the travel time calculations clearly indicated that the
primary problem leading to excessive DBF levels was
the operation of SmallWater's water distribution system
rather than the source water/treatment. SmallWater's
consultant was asked to  work with the town's  water
staff to determine operational changes for reducing the
water age within the town.

Problem #2 Contamination Scenario
SmallWater has received several sporadic complaints
over the past year from the residents in the trailer park
in the southwestern part of town about water that oc-
casionally tastes and smells  bad. The water system op-
erator has visited the area on a few occasions and has
not found any obvious problems. There haven't been
any positive conform samples in the town for the past
year.  Recently, one resident mentioned that both their
children and elderly mother have experienced severe
stomach aches.

Issues to Consider
The patterns of complaints  in the trailer park suggest
that there may be some intermittent contamination
occurring in the distribution system serving this area.
Since the complaints are from more than a single resi-
dence, it is likely that the location of the contamination
is in the distribution system itself or possibly within the
customer's plumbing that has then migrated through
the distribution system. Also, since the trailer park is
served by a single connection to the main part of the
distribution system, it is likely that the contamination
usually will stay  in the trailer park piping rather than
move more widely into the  distribution system.  There
are no Total Conform Rule (TCR) sampling sites in the

      Figure 5.3 Water Age Within Small Water,  USA
      trailer park which may explain why there have been no
      positive coliform readings.

      Regulatory Guidance
      The town has fulfilled the sampling requirements as-
      sociated with the TCR and  has  not experienced any
      positive  readings. However,  the  repeated complaints
      within a small area and especially  the recent indications
      of possible gastrointestinal illness should alert the town
      to a  potential serious problem.  SmallTown  officials
      should contact the state primacy and health agency and
      solicit its assistance. Other activities should include (1)
      a cross-connection investigation in the trailer park area;
      (2) additional coliform sampling in the trailer park area;
      and (3) medical testing of the  sick residents for possible
      exposure to disease-causing coliforms such as E. coli.

                         Distribution System
                        Water Quality  Issues
4 Odor commonly caused by bacteria growing
  in a sink drain
7 Plastic pipes are susceptible to contamination
  from surrounding soils when this occurs
8 Water appearance caused by entrapment of
  air bubbles
9 Shock-waves caused by abrupt changes in
  velocity and direction of water
10 Technical term for process that converts
   ammonia to nitrate in distribution system
11 Water colors associated with manganese or
   other pipe sediments
              1  Forms due to precipitation of minerals in
                water on to the pipe walls
              2  Water colors associated with corroding iron
              3  Water colors associated with corrosion of
                copper plumbing
              5  A result of a cross-connection where
                nonpotable water contaminates drinking
                water distribution system
              6  Common technique used for biofilm control
                which can sometimes lead to undesirable
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Chapter 6

Distribution System

Monitoring,  Control,

and  Security

There are many questions that arise when attempt-
ing to monitor, control and/or secure a distribution
system.   Some of these questions include the  fol-

   •  What is happening at any moment in the
     underground pipes, elevated tanks, pump
     stations and other components that make up
     the distribution system?

   •  Are pressures sufficient to meet customer
     demands, prevent infiltration, and provide fire

   •  Is there sufficient chlorine residual to protect
     the water in the distribution system?

   •  Is there enough water in the tank in case of a
     major fire?

   •  Has a contaminant entered the water system
     that could lead to a waterborne disease

   •  When opening a hydrant, how much flow is

   •  Does the distributed water quality meet the
     standards set by EPA and the state regulatory

In order  to answer these  questions with  some de-
gree of accuracy and reliability, data must be  col-
lected and reviewed periodically by the utility  per-
sonnel from a variety of sources.  If any  problems
are observed, corrective actions must be taken by
the utility personnel.  Utility managers may want
to consider automated monitoring for operating and
controlling a distribution system. Automation assists
in obtaining a continuous set of records that can be
examined for improving system operations. A distri-
bution system is one of the most vulnerable aspects
of a water utility because its components are geo-
graphically dispersed, making it difficult  to ensure
physical integrity.  However, some key distribution
system components, such  as finished water storage
tanks, can be adequately secured. Automation may
therefore help improve the  overall security of the
distribution system.  This chapter discusses options
for monitoring, controlling and securing a distribu-
tion system.
6.1  Monitoring a Distribution
Monitoring can be broadly categorized as measuring
the hydraulic state of the water in a distribution sys-
tem,  or measuring water quality parameters.  These
two  aspects of  distribution system monitoring are
discussed further in Sections 6.2 and 6.3. Hydraulic
state monitoring includes: measuring flow rate, water
pressure, velocity and/or water levels within a tank
or reservoir. Water quality monitoring involves meas-
urement of the intrinsic characteristics of the  water.
For example, a representative sample of water may be
analyzed for temperature, conductivity, and pH.  In
addition, the water can be analyzed for specific wa-
ter quality parameters such as chlorine residual and
                   Doc, the sampling guide said to grab
                      a sample and store at 39ฐF
                     t-t-til the t-t-time of analysis!
Specific monitoring procedures may range from sim-
ple manual sampling to a highly automated process of
sample collection and analysis. In manual sampling, a
water sample is taken from the distribution system and
is either analyzed in the field (Figure 6.1) or transport-
ed for analysis in the  laboratory.   Automated moni-
toring typically requires more sophisticated and costly
equipment, but provides savings in labor costs and the
added benefit of a greater number of measurements.
Historically, small water utilities have generally relied
upon manual sampling procedures in order to avoid the
capital  investments associated with automated equip-
ment.  However, as technology costs decrease, there
are many cases where automated monitoring equip-
ment is cost-effective for smaller utilities.  Figure 6.2
shows an example schematic of an automated sampling
unit that measures and analyzes the sample in the field
and sends the information back to a central office for

Figure 6.1  Manual Water Quality Sampling and Field

      Since monitoring activities are expensive, they are usu-
      ally performed to meet a specific objective or multiple
      objectives. These objectives may include:

         •   Regulatory requirement - Taking samples of
            water to determine if it meets the requirements
            established by federal or state agencies

         •   Process control requirement - Providing real-
            time information that assists in operating the

         •   Baseline data collection - Establishing normal
            ranges for data values from the system

         •   Contaminant identification - Detecting the
            presence of a contaminant that has intentionally,
            accidentally or naturally entered the water

         •   Computerized model calibration - Collecting
            hydraulic or water quality data to be used in
            adjusting a hydraulic and/or water quality model
            of the distribution system
Figure 6.2  Automated Water Quality Monitoring
(GCWW, 2007)

   •   Improving system performance - Collecting
      real-time information that may be used to
      understand and improve system performance

In the following  sections, various available options for
distribution system state and water quality monitoring
are discussed.

6.2  Distribution System  Hydraulic
As water moves  through  a distribution system and its
various components,  hydraulic characteristics  such as
flow, velocity, and pressure change over time.   In order
to understand a system's operation, to identify potential
problems, or to operate the system more efficiently, it is
useful to monitor these characteristics.  Measurements
may be made continuously at key locations using auto-
mated monitors (if affordable) or be measured manually
at selected locations and times.

6.2.1  Flow and Velocity Monitoring
Flow is an important factor in understanding the opera-
tion of a distribution system.  Low flows in some pipes
may indicate a constriction or closed valve. High flows
can result in high velocities which cause large friction
losses and even damage to the pipe. Water sold to cus-
tomers is typically billed based on flow. Therefore, un-
derstanding flow is important to the proper operation and
maintenance of a water distribution system.

Meters are used to measure flow rates and velocities in
an open channel or closed pipe. They may be perma-
nently placed in the distribution system or in a treatment
plant to provide continuous measurements. They may
also be temporarily installed as part of a testing program
to provide measurements over  a period of a few days
or weeks.  They may also be used manually to measure
flow from a hydrant as part of a system calibration or fire
flow analysis. Flow meters can provide continuous flow
measurements and/or totalized volumes over a period
between readings.

There are several different types of flow meters.  Most
meters can be broadly  classified based on the following
operating principles: differential pressure, positive dis-
placement (PD), velocity measurement and level meas-
urement. Differential pressure meters and velocity meters
are most commonly used in the water industry. Within
each of these categories, there are alternative methods for
achieving these measurements. Table 6.1 illustrates sev-
eral different types of flow meters and the basic principle
upon which each is built.  More detail on the limitations
and advantages of each type of meter can be found in
American Water  Works Association's (AWWA's) M33
Manual of Water  Supply Practices "Flowmeters in Water
Supply" (second edition published in 2006).

Table 6.1  Flow Meters (Partially adapted from AWWA,  2006b)
      Meter Type
 Venturi Meter
                             - High-Pressure Port
             Principles of Operation
                                      A constricting section is placed in the pipe causing
                                      an increased velocity and corresponding pressure
                                      drop.  Pressures are measured at the upstream end
                                      of the constriction and within the constriction. Flow
                                      is calculated from the square root of the measured
                                      pressure differential multiplied by a meter factor
                                      that accounts for dimensional units and discharge
 Turbine and Propeller
Vanes	v
In turbine and propeller flowmeters, flowing water
strikes rotor blades that rotate at a rate proportional
to the flow velocity. The turbine wheel of a turbine
meter generally fills the cross-section of the pipe
and is mounted to spin freely between two central
bearings supported in the pipe wall. The propeller
of a propeller meter is mounted on bearings at the
downstream end of the pipe and does not fill the
meter cross-section.
 TransitTime Ultrasonic
 Flow Meter
                                      A pair of transceivers is positioned diagonally across
                                      the meter body. The transceivers transmit  and re-
                                      ceive an ultrasonic pulse in the direction of flow, fol-
                                      lowed by a return pulse against the direction of flow.
                                      The time difference between the two pulse transmis-
                                      sions through the stream is a function of fluid veloc-
                                      ity and,  by computation, the rate of flow.
 Averaging Pitot Flow
                                      Multiple ports in an insertion tube face upstream
                                      into the flow to provide sampled pressures at
                                      selected points along the vertical pipe diameter to
                                      provide an averaged pressure over the pipe cross-
                                      section while ports facing downstream register
                                      static pressure. The device produces a differential
                                      pressure reading which is used to calculate velocity
                                      (proportional to the square root of the pressure
 Insertable Averaging
 Magnetic Flowmeter
                                      Multiple magnetic fields are generated by electro-
                                      magnetic coils placed inside a sensor inserted in
                                      the pipe section through a tap connection. Water
                                      passing around each sensor encounters the mag-
                                      netic field, which induces a small electric charge
                                      that is proportional to the velocity of the water in
                                      the magnetic field. The electric charge is sensed by
                                      multiple pairs of electrodes in contact with the water
                                      adjacent to each of the electromagnets. Each coil
                                      and pair of electrodes becomes an electromagnetic
                                      velocity sensing point along the  sensor.
 Variable Area Flow
                                      Also known as a rotameter, the area through which
                                      the liquid flows is permitted to vary so that a con-
                                      stant differential pressure is maintained. The basic
                                      elements are a vertical conical tube and a cylindri-
                                      cal float that is free to rise and fall in the tube. The
                                      greater the entering volumetric flow, the larger the
                                      required flow through area, and the higher the float
                                      rises. Therefore, the rise of the float is proportional
                                      to the rate of flow.

      Flow measurements may also be taken at hydrants
      and used to estimate fire flow availability (or as part
      of a distribution system model calibration study). Pitot
      gages are typically used to measure hydrant flow and
      are available in three forms: hand held, clamp-on, or in
      combination with diffusers (see Figure 6.3).  They are
      all based on the principle that virtually all of the veloci-
      ty head in the hydrant flow is converted to pressure head
      that is read by the pitot gage.  Pressure measurements
      can then be  converted to hydrant discharge rates based
      on the diameter of the hydrant port, the characteristics
      of the port and the specific instrument.
Figure 6.3 Hydrant Flow Gages

  Water Meters and Automation
  Positive displacement (PD)  water meters are normally
  used to measure usage in residences  and commercial
  buildings.  Other types of flow meters can also be used
  at specific locations in a distribution system to determine
  flow through that portion of the system.  These flow me-
  ters utilize a variety of flow measurement methods and are
  generally selected for specific use based on the type of end
  user, the required flow rates, and accuracy requirements.

  PD meters employ oscillating pistons or a nutating disk to
  measure flow.  Both methods  rely upon the physical dis-
  placement of the measuring element in direct relation to
  the amount of water passing through the meter. The piston
  or disk moves a magnet that drives the register. PD meters
  are generally very accurate at low to moderate flow rates
  typical of residential and small commercial users, and are
  common in sizes from 5/8 to 2-inch pipe-size. However,
  this measuring methodology is not practical in large  com-
  mercial applications that experience high flow rates or low
  pressure loss.  A velocity type meter is commonly em-
  ployed for higher flows where the velocity is converted
  into volume. Common velocity-based meters include:  jet
  meters (single-jet and multi-jet), turbine meters, propeller
  meters, and magnetic meters.

  Manufacturers have now developed pulse or encoder reg-
  isters to produce electronic output for radio transmitters,
  reading storage devices,  and data logging devices that
  are employed with Automatic Meter Reading (AMR).  In
  AMR technology, the usage data is automatically collected
  from customer water meter and transferred to a central da-
  tabase for billing and/or analyzing. AMR systems provide
  customers and utilities a more accurate  way of tracking
  and billing of actual water usage rather than depending
  on a flat rate system or an estimate.  AMR technologies
  include handheld, mobile and network technologies based
  on wired, wireless,  or radio frequency transmission.

6.2.2 Pressure Monitoring
Pressure measures the amount of internal energy within
water at any location in the distribution system.  Most
importantly, pressure  serves as an important indicator of
how a water system is operating and is closely related to
hydraulic integrity. Routine low pressures in a distribu-
tion system  indicate design deficiencies or operational
problems in the system. Unusually low pressures may
indicate a problem such as a main break, closed valve
or low water levels in a tank.   Therefore,  pressure is
frequently monitored to assess system operation  and

Pressure can be monitored continuously using pres-
sure meters installed  in the system or can be measured
manually at hydrants or any faucet in the distribution

                  My dad put automatic water meters and
                   valves throughout the house and the
                  shower shuts off after 15 gallons use!
      system.  Permanently installed continuous monitors
      are frequently connected to a Supervisory Control and
      Data Acquisition (SCADA) system (See Section 6.4
      for an overview on SCADA and automation). These
      pressure values are transmitted to a central control
      room. Pressure meters may also be used to measure
      tank  water levels. Figure 6.4  shows a pressure gage
      attached to a fire hydrant. Figure 6.5 shows typical
      SCADA readouts of the distribution system hyraulic

      6.3 Distribution  System Water
           Quality  Monitoring
      Water utilities strive to  deliver water that meets or
      is better than the Safe Drinking Water Act (SDWA)
      standards and is aesthetically acceptable. Other goals
      may  include minimizing treatment costs and deliver-
      ing a product that is consistent in quality for all uses.
      Water quality monitoring serves as the mechanism for
      measuring how well the utility meets these goals and
Figure 6.4 Digital and analog pressure meter attached
to fire hydrant
may serve multiple purposes including:

   1.  Satisfying regulatory compliance requirements

   2.  Assisting in process or operational control

   3.  Identifying contaminants in the water

   4.  Characterizing the water quality for use in future

Because water quality  monitoring can be expensive,
most small utilities emphasize its use only in meeting
regulatory compliance  requirements.  However,  ad-
ditional monitoring can frequently pay off in terms of
an improved product and lower treatment and  chemi-
cal costs. Routine or automated online monitoring can
also assist in screening for the possible occurrence of:
loss of disinfection residual, pathogen contamination,
disinfectant byproduct  formation, nitrification, metal
accumulation, and intentional (e.g., terrorist) contami-

Design of a monitoring or sampling program involves
the following decisions:

   1.  What constituents should be monitored?

   2.  Where should the monitoring locations be

   3.  What type of sampling (continuous, composite
      or grab) should be employed?

   4.  How often should sampling occur?

   5.  What type of analytical procedures should be

   6.  Is the sampling routine, seasonal, or being
      conducted for a special study?
Figure 6.5 Readout meters for flow, water level and
pressure from a SCADA system

      For compliance  monitoring, the answers to most of
      these  decisions are spelled out in the regulations and
      operating permits.  However, for other types of moni-
      toring, the water utility is responsible for designing the
      monitoring program that meets  its specific needs and
      fits within its budget.
          Honestly ma'am, the computer |
          virus ate our monitoring and  h
              compliance records!     J
      6.4  Controlling a Distribution
      The smaller utilities  have  historically limited the use
      of SCADA to control the treatment process. However,
      SCADA is routinely employed by larger utilities to moni-
      tor and control distribution system operations. A SCADA
      system  consists of three components: instrumentation
      and hardware, a software program or operator interface,
      and communication media.  In the past, most small sys-
      tems could not afford SCADA systems because the initial
      equipment cost was high and it required a highly trained
      technical person to effectively operate the SCADA on a
      routine basis.  However, with more sophisticated technol-
      ogy updates, costs have become more reasonable. Fur-
      thermore, the degree  of sophistication (and customiza-
      tion of the programming) allows for a less skilled person
      to operate the system effectively. The implementation
      of appropriate automation and control technology (e.g.,
      SCADA) can greatly enhance operations and mainte-
      nance activities for small utilities.  The key components
      of SCADA systems, along with some basic selection cri-
      teria, are described in the following subsections.

      6.4.1 SCADA Instrumentation and Hardware
      Instrumentation and hardware are generally the most
      expensive components of a SCADA system.  In order
      for an instrument to be connected to a SCADA system,
      it must  generate an output  signal that the SCADA can
      read.  Sophisticated monitoring instruments generally
      have a local display and an optional standard external
analog or digital output. The analog output is usually a
direct current output of 1 to 5 volts or 4 to 20 milliam-
peres which can be interfaced with standard SCADA
input/output (I/O) hardware. Through calibration, this
signal can then be directly related to the instrument
reading, such as chlorine concentration in milligrams
per liter or turbidity in nephelometric turbidity units.
Similarly, a pump's operating state would have a pre-
defined digital output (e.g., 1 or 0) where the value re-
turned would directly correspond to the operating state
of the pump (i.e., 1 = off and 0 = on, orvice versa).

Information also travels  in the  opposite  direction
through the SCADA system. In this case, the central
system sends an analog or digital signal to the instru-
ment in order to initiate some action by the instrument.
The digital signals are used to control all system com-
ponents from relays to motor starters.  The analog sig-
nals  are used to control variable frequency drives and
other variable speed pumps and motors.
                                                                               Would we be able to send an alarm to
                                                                              our vendor when the cookie supplies are
                                                                               running low on the vending machine?
The analog and digital I/O values are aggregated, com-
puted and communicated by field SCADA devices such
as programmable logic controllers or micro-processor
based remote terminal units (RTUs).  Field RTUs may
be connected to other master RTUs or computing devic-
es such as a personal computer that contains customized
software  which provides the human machine interface
or the SCADA operator interface. The cost of the RTUs
can range between $200 and $20,000, depending upon
the features and complexity desired.

6.4.2 SCADA Operator Interface
The  price  of commercially  available customizable
SCADA  software usually depends on the number of
I/O channels licensed for use along with the number
of computers or workstations from which the system is
operated. The cost of SCADA software has decreased

over the past few years and the ease of customizing
SCADA software has improved dramatically. The most
sophisticated packages, designed to work with a variety
of hardware, are relatively expensive (between $1,000
and $20,000 for a utility with I/O channels numbering
between 50 and 1,000) and generally require a trained
programmer for the initial setup.  For less complicat-
ed uses,  such as by a small water utility with minimal
staffing,  a package  arrangement (where  the software
is included with the hardware and basic programming
setup) is usually sufficient.

Generally, SCADA equipment  that is  located within
a treatment plant  is hard-wired.  Distribution system
components, such as tanks and pumps that are scattered
throughout the  distribution system, need alternative
communication media such as leased lines or wireless
transmission capability.  Small systems that are rela-
tively compact should explore the use of standard in-
dustrial wireless radio modem connectivity where pos-
sible. Other hard-wired and wireless options available
to commercial carriers (such as the phone company)
require a monthly fee that may range between  $20 and
$200 per month, depending upon the selected  solution
and required data bandwidth requirement.

If a small system operator is considering the installation
of a new SCADA system, the following factors should
be carefully considered:

   •   Does the treatment and distribution system
      justify the need for a SCADA system (is
      it spatially dispersed and are its various
      components difficult to access)?

   •   Is the treatment plant and the distribution system
      amenable to automation?

   •   What types of communication media can be
      used (phone, radio,  cellular, etc.) at the critical
      locations in the system?

   •   How much existing automation and control
      instrumentation is available in the system that
      could be incorporated into the SCADA system?

   •   What type of SCADA system is needed (is the
      goal to monitor and /or control operations)?

   •   How many parameters need to be monitored
      and/or controlled?

   •   Are there any specific regulatory monitoring and
      reporting requirements that can be met by using
      a SCADA system?

   •   Can the selected SCADA system be made
      compatible with existing or future use of AMR?
Remote Monitoring - Coabvood, West Virginia (EPA, 2003d)
In 1992, EPA, in collaboration with the McDowell County Public
Service District (MCPSD), installed a prefabricated semi-auto-
mated ultrafiltration (UF) drinking water treatment package plant
in Coalwood, West Virginia (WV).  The UF system was located
approximately  12 miles from the MCPSD office  in the Appa-
lachian Mountains. The UF system has been in operation since
1992, and has been providing water of good quality to the com-
munity. However, upon completion of the two-year project, it be-
came apparent that the MCPSD would be unable to meet the WV
Department of Health monitoring and reporting guidelines. These
regulations require that the treatment operator(s) maintain daily
records of specific operating and treatment parameters.  Routine
monitoring of the water distributed from the UF treatment process
was resulting in significant costs for associated time and travel.
Furthermore, during inclement  weather conditions, completion
of these routine tasks became extremely difficult.  Similar moni-
toring requirements at other remotely located sites also required
MCPSD to dedicate a considerable amount of staff time to com-
plete these routine tasks.   Therefore, in 1998, the EPA extended
the research project by installing and testing an off-the-shelf user-
friendly Windows-based SCADA system.  The SCADA system
selected was fairly inexpensive, smart, user-friendly and scalable.
The total cost for the hardware and software for setting up the
SCADA system at the WV test site was $35,000. Table 6.2 pro-
vides a breakdown of the SCADA system costs:
      6,2  Cosf of SCADA                  at
Coalwood, WV.
Computer, Instrumentation, Software, and
Communication Modem and Phone Line
Data Collection and Transportation Terminal
Instrumentation for Monitoring and Control
Setup and Installation
Total Capital Cost
The remote capability allowed the utility to save on labor and
mileage for performing daily monitoring.  A simple cost-benefit
(retum-on-investment) analysis showed the advantages of such
a system. The site was approximately 24 miles round trip from
MCPSD headquarters and it took the operator one hour per day to
perform this task.  The annual labor savings (based on an operator
labor rate of $15/hour) amounted to: $15 per hour X 1 hour/day
X 365 days/year = $5,475. In addition, the vehicle cost savings at
the rate of $0.40 per mile amounted to: $0.40 per mile X 24 miles/
day X 365 days/year = $3,504. In total, a minimum of $8,979
in annual savings to the utility was achieved immediately for
this site. A direct payback, based on cost savings to satisfy daily
monitoring requirements, was achieved in less than 4 years. This
simplified cost model was  based on direct operating costs only
and assumed that the cost of upkeep of monitoring instrumenta-
tion was similar to other laboratory devices used by the  opera-
tor. Additional benefits included the ability to maximize the effi-
ciency of the water treatment operations, creation of an advanced
knowledge of the systems condition prior to performing any site
visits for troubleshooting and repair, improving the security of the
system, and improving regulatory monitoring compliance.

         •   Can the SCADA system be classified as a capital
            improvement project and acquired through
            outside sources of funding such as grants and
            interest-free loans?

         •   What is the return-on-investment or labor cost
            savings resulting from installing a SCADA

      Considering these factors will help a utility determine
      the need, affordability, and the basic design of a SCADA
      system. These factors will also help to determine if the
      SCADA system will complement general utility opera-
      tions. Retrofitting a treatment and distribution system for
      a SCADA system can be cost-prohibitive because many
      currently operating small utilities were not originally de-
      signed for remote operations.  Therefore, they have lit-
      tle or no existing electronic instrumentation or hardware
      that can be integrated into a SCADA system, and the cost
      of upgrading the utility for remote operations could be
      significant.  It is essential that a cost-benefit analysis be
      performed prior to such implementation.
 [Under this new water rate plan, anyone can reduce
 |  their current water bills by 10%... if they take
      showers and cook during off-peak hours!
      6.5  Securing a  Distribution System
      The Public Health Security and Bioterrorism Prepared-
      ness Act of 2002 mandated that drinking water utilities
      serving more than 3,300 persons conduct vulnerability
      assessments (VAs)  and develop emergency  response
      plans (ERPs). EPA provided funding or training as-
      sistance to utilities to  assist in compliance with the
      Act.  The compliance schedule was staggered based
      on system size.  The last scheduled date for preparing
      a certified ERP was December 31, 2004, for systems
      serving between 3,300 and 50,000 persons.  For sys-
      tems serving fewer than 3,300 persons, EPA developed
a guidance document titled, "Drinking Water Security
for Small Systems Serving 3,300 or Fewer Persons."
There are a variety of guidance documents and tools
available on the Internet for addressing small systems
security that were collaboratively developed and fund-
ed by a variety of organizations including: EPA, state
environmental agencies, Department of Homeland Se-
curity, National Rural Water Association, and the Rural
Community Assistance Program. Small water utilities
are strongly encouraged to use these sources as much
as possible.

The VA process identifies the critical water utility as-
sets that may be subject to potential threats. If these
assets are successfully targeted, the consumer's health
could be compromised or there could be severe infra-
structure and economic damage. The ERPs address the
risks associated with these vulnerabilities and contain
procedures that eliminate, minimize,  and/or manage
these  security  breaches. An overview of distribution
system vulnerabilities, operational and emergency re-
sponse mechanisms is presented in the following  sub-

6.5.1  Distribution System Vulnerabilities
Distribution systems and their components are vulner-
able to two types of attacks. In one scenario, the system
component could  be physically destroyed or disabled;
in the other scenario, the component may be contami-
nated with a chemical and/or biological threat agent. In
                                                                               Our security budget only had
                                                                             enough money to buy these signs.
                                                                              Go ahead and post them... they
                                                                               might discourage the vandals,

addition to security threats, distribution system compo-
nents are vulnerable to aging and corroded pipes. Pipes
located below the water table provide an opportunity for
intrusion of water and contaminants (e.g., animal and
human wastes) if low or negative pressure conditions
occur.   Maintaining the hydraulic integrity (positive
pressure) of a water distribution system is important,
given that insufficient pressure  can lead to infiltration
or backflow through cross-connections (see Chapter
5). Infiltration or backflow can occur during fluctuating
water use patterns (e.g., fire prevention activities/fire
hydrant use, power outages, and flushing exercises).

Post-treatment contamination can occur during the stor-
age of drinking water. Storage facilities are particularly
vulnerable to contamination due to the failure of pro-
tective covers  or barriers, or open hatches and vents.
Birds, insects, animals,  rain, and microorganisms can
even contaminate covered finished water storage tanks.
Routine inspections and maintenance are necessary to
address this vulnerability.

6.5.2 Operational and Emergency Response
EPA strongly recommends that utilities develop a for-
mal ERP  that contains  the  following eight core  ele-

   1.  System-Specific Information - At a minimum,
      identify the utility staff and contact person(s)
      with the location of critical documents, such as
      distribution system maps, as-built drawings, site
      plans, source water locations, current equipment
      inventory and operations manual(s).

   2.  Community Water System Roles and
      Responsibilities - The plan should designate an
      Emergency Response Lead with an alternate.
      This person should be  designated as having
      the responsibility for evaluating incoming
      information, managing resources and staff, and
      deciding on appropriate response actions. This
      person should also have the lead responsibility
      of coordinating emergency response efforts with
      first responders.

   3.  Communication Procedures: Who, What,
      and When - The plan  should clearly identify
      communication channels for utility staff and
      personnel, external non-utility entities (such as
      other city, state and federal agencies), and the
      public/media. The plan should contain internal
      and external notification lists with information
      on all appropriate entities to be contacted,
      including their names, titles, mailing addresses,
      e-mail addresses, all applicable land line and
      cellular phone numbers, and pager numbers.
      These lists should be updated as necessary.
4.  Personnel Safety - During an emergency,
   personnel may be at risk of harm, injury, or
   even death. Therefore, protecting the health
   and safety of the utility, first responders, and
   the surrounding community should be a key
   priority. An ERP should provide direction to
   personnel on how to safely implement a variety
   of response actions.

5.  Identification of Alternate Water Sources - The
   plan should contain information on the amount
   of water needed to address both short-term
   (hours to days) and long-term (weeks to months)
   outages. The ERP should identify potential
   alternate water supplies that can be quickly
   mobilized during both types of outages.

6.  Replacement Equipment and Chemical Supplies
   - The plan should identify the location of the
   current equipment inventory that contains the
   listing of equipment, repair parts, and chemicals
   that would be needed to respond adequately
   to a particular vulnerability. The utility should
   consider establishing mutual aid agreements
   with other nearby water utilities to address any
   deficiencies. These agreements should identify
   the equipment, parts, and chemicals available to
   the utility under the agreement.

7.  Property Protection - Protecting the utility
   facilities, equipment and vital records at the
   utility is essential to restoring operations once
   a major event has occurred. Therefore, the
   ERP should identify measures and procedures
   that include: "Lock down" procedures; access
   control procedures; establishing a security
   perimeter following a major event; evidence
   protection measures for law enforcement
   (should the major event also be declared a crime
   scene); securing buildings against forced entry;
   and other property protection procedures and

8.  Water Sampling and Monitoring - The ERP
   should clearly identify water sampling and
   monitoring requirements. To the extent
   possible, the ERP should identify and address
   special water sampling and monitoring issues
   that may arise during and after a major event.
   Some water sampling and monitoring issues to
   consider include: identifying proper sampling
   procedures for different types of contaminants;
   obtaining sample containers; determining the
   quantity of required samples; identifying who
   is responsible for taking samples; identifying
   who is responsible for transporting samples (in
   time-sensitive situations); confirming laboratory
   capabilities and certifications; and interpreting
   monitoring or laboratory results.

     I! only have $100 in our emergency
   communications budget but I got a I-
     great deal on 5 miles of string.   J
      An ERP containing these eight core elements provides
      the necessary information to effectively coordinate and
      respond to an emergency event.  In addition, the util-
      ity staff should be trained on procedures and conditions
      that necessitate the activation of the ERP.  Thereafter,
      operational actions must be implemented to identify the
      source of contamination, to isolate the source (if pos-
      sible), and to determine the  operational changes neces-
      sary for containing the damage to public health and the
      distribution system. Finally, steps must be undertaken
      to discharge or transport the contaminated water to a
      location where it can be effectively treated for disposal.
      An ERP should be viewed as a "living document" that
      is frequently updated as changes are made in the sys-
      tem, its operation and its personnel.
                  6.6 SmallWater, USA -
                       Monitoring,  Control
                       and Security  Problem
      Problem #1 Monitoring and Control
      Water samples from the distribution system indicate
      that SmallWater has had trouble maintaining residual
      chlorine  levels in the distribution  system. Residual
      chlorine  levels were frequently near zero at the most
      distant locations (supplied by the elevated tank) in the
      distribution system. SmallWater is considering booster
      disinfection at the tank and installing a continuous chlo-
      rine monitor to collect data for optimal disinfectant dos-
      age and to control the chlorine dosage rate.

      Issues to Consider
      Maintaining adequate residual disinfectant levels is es-
      sential from a compliance  perspective  and to ensure
      a safe water supply.  However, the cost  of installing a
      booster chlorine station and an online chlorine monitor
      with an analyzer can be quite costly. Costs may range
      between  $1,000 and $2,000 for the  monitor and  con-
necting it to a SCADA interface to control the booster
dosage of chlorine will require additional funds (new
SCADA remote terminal unit ~$2,500, installation and
testing ~$3,000). Additional funds are required for the
chlorine storage unit and the injection pump.

In order to take better advantage of the costs associ-
ated with the booster chlorination station, other uses of
the SCADA at this location should be investigated. The
utility may achieve some operational efficiency if the
operation of the tank can be optimized by using the tank
level indicators and integrating them with the SCADA
system for booster chlorination. Understanding tank hy-
draulics and mixing processes within the tank and their
potential  impact on loss of chlorine residual may result
in further efficiencies  and better performance. Online
residual chlorine data are also useful if there is a great
deal of variation in the regular weekday, weekend and
seasonal data.

Problem #2 Security Scenario
Security at the elevated tank has been an ongoing issue.
The tank property is not fenced and has been broken
into several times. Birds, animals and insects have pe-
riodically contaminated the tank and dead species have
been found in traps at access locations.

First and foremost, the tank access must be physically
secured. Barriers (e.g., doors, wire mesh or iron bars)
and locks must be placed on all hatches, vents, gates,
and other points of entry to prevent access by unau-
thorized personnel, birds, animals  and insects. Dead
bolt locks and lock guards are fairly inexpensive and
provide additional security at minimal cost. A  daily
check of critical system components enhances security
and ensures that there  has been no unauthorized entry.
Doors to  critical facilities, and their hinges, should be
constructed of heavy-duty reinforced material. Hinges
on all outside doors should be located on the inside.

To further enhance security, SmallWater should consid-
er installing access alarms on all points of entry utiliz-
ing the SCADA system  (see Problem #1).  Integrating
SCADA with security and monitoring/compliance re-
quirements is extremely cost-effective.

             Distribution System Monitoring,
                      Control, and  Security
4 Type of commonly used pressure-based
6 Flowmeter using sound waves to measure
8 A term for protecting utility property from
                  1 Term for periodic measurement of water
                    quality in distribution system
                  2 Abbreviated term for most commonly used
                    water meters for residential applications
                  3 Acronym for a plan to address risks associ-
                    ated with vulnerabilities
                  5 Recommended number of core elements of
                    an Emergency Response Plan
                  7 Acronym for Supervisory Control and Data
                    Acquisition System
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    Chapter  7

    Strategies to  Address

    Distribution  System

    Water  Quality Issues

    In the U.S., a concept called the "multiple barrier ap-
    proach" (as discussed in Chapter 2) has been applied
    widely to drinking water treatment.  This includes the
    use of both disinfection and nitration to  treat surface
    water prior to supplying it to the consumer. However,
    under the Safe Drinking Water Act (SDWA) and its
    amendments, this concept has been expanded by EPA to
    include source water protection and distribution system
    integrity. The 1996 Amendments to the SDWA empha-
    sized source water protection; more recently, EPA has
    focused on drinking water distribution systems.  The
    most recent "report card" issued by the American So-
    ciety of Civil Engineers addressing the nation's drink-
    ing water infrastructure reveals that distribution system
    infrastructure improvements will require a tremendous
    investment if they are to provide an effective barrier in
    protecting the nation's drinking water.

    Many  small-  and medium-sized distribution systems
    built prior to World War II (especially those serving ru-
    ral areas) have received little or no recent capital invest-
    ment.  Some of these systems are facing water quality
    problems that are associated with aging infrastructure.
    In addition, some utilities  are experiencing a higher
    rate of pipe failures and problems with specific pipes
    manufactured during a certain period of time, or when
    they are subjected to certain environmental conditions.
    Common problems include: corrosion, biofilm growth,
    frequent breaks and leaks,  and difficulty in minimiz-
    ing disinfectant loss and disinfection byproduct (DBF)
    levels. Cross-connection and backflow issues are also
                         i-   \
[Ah! here is the quarterly compliance
 report for Small Water. I knew they
  were cutting back on mail costs.  ,
frequently observed in these systems. To address these
issues and find long-term solutions, small- and medi-
um-sized utilities need to step back from a "crisis man-
agement mode" and engage in strategic planning. For
example, when a water quality problem is discovered
and the cause isolated, the utility must address immedi-
ate problems related to public health.  However, util-
ity mangers should also explore strategies that address
long-term issues. Some of these changes may require
long-term, phased infrastructure investment. This chap-
ter provides an overview of these operational, financial
and management strategies.

7.1 Operational Strategies
Operational changes are generally less expensive and
easier to implement than  changes that require signifi-
cant infrastructure investment.  For example, if DBFs
are  an issue, the utility should consider actions that
minimize DBF formation in the  distribution system.
The utility might consider reducing water age and/or
changing disinfectants (e.g., chlorine to chloramine) or
both. Switching disinfectants to chloramine will  likely
require some capital investment. In some cases, these
operational changes may only provide temporary relief
and eventually an infrastructure investment may be nec-
essary. The utility may need to find an alternative source
of water or treat the water in  such a way as to  lower
the total organic carbon (TOC) content in the finished
water.  A summary  of available operational strategies
is presented in the following sections of this chapter.
Some of these operational strategies are not presented
in detail here as they  have been previously described
within various chapter-specific problem scenarios (see
Chapter 4 and 5).

7.1.1 Reducing Water Age  in the Distribution
There are several indicators of excessive water age in-
cluding: taste and odor complaints, discoloration, low
disinfectant residual concentration, elevated DBF level,
elevated bacterial count, and elevated nitrite or nitrogen
levels.  "Old" water, especially in warm environments,
promotes the growth of microorganisms. Such micro-
organisms impart taste and odor issues or enhance nitri-
fication. Low-flow and dead-end areas within a distri-
bution system generally accumulate sediments; during
high-demand periods, these sediments may be stirred
up, resulting in discolored water.

From an operational perspective, tanks, valves, main
size and pumping rates have a direct impact on water
age.  Finished water storage facilities may exhibit poor
mixing conditions because tank turnover is limited by
minimum fire-fighting capacity requirements.   Tank
mixing can also be optimized either by cycling the tanks
periodically or installing mechanical devices, such as

      diffusers and nozzles to achieve higher velocities which
      results in better mixing.  Valve settings and pumping
      rates determine water velocities and flow direction. Ve-
      locity, in turn, impacts hydraulic pathway and retention
      time.  In some cases, operators can adjust system pres-
      sures  and position the valves in such a way as to induce
      flow within the distribution system in a direction that
      can minimize water age.  The utility can also initiate
      flushing programs to displace "old" water.
        Hold it, young drop... this is a "dead-end" of
         the distribution system; I have been here for
         almost 8 days now — that is roughly 120 in
         water droplet years, so I'm next to be used!

                                  1 *
      7.1.2  Adapting  Operations  to  Meet  System-
             Specific Water Demands
      Water demand is a driving force that affects all public
      water system (PWS) operations.  However, water de-
      mands vary significantly and system operators must
      have a good understanding of the amount of water be-
      ing used, where it is being used,  and how this usage
      varies with time.  For example, for most PWSs, the
      ratio of daily average to daily maximum water demand
      ranges from 1.2 to 3.0, and the ratio of the daily aver-
      age to the peak hourly demand ratio may vary between
      3.0 and 6.0.  Seasonal variations  may make these ra-
      tios even more  extreme.  Fortunately, these demand
      values are system-specific and can be quantified based
      on experience.   Demands are generally classified as

         •   Baseline demands - Corresponds to consumer
            demands  and unaccounted-for water associated
            with daily average operating conditions.

         •   Seasonal  Demand - Water use typically
            varies over the course of the year with higher
            demands  occurring in the warmer  months, due
            to watering of lawns and recreational use (e.g.,
            swimming pools).

         •   Fire demands - Typically, the most important
            consideration for water system design.
   •   Diurnal (daily) demand variations -
      Continuously varying demands which are
      inherent in a PWS and typically increase during
      the daytime hours.

As discussed previously, water distribution systems are
basically a networked conveyance mechanism in which
pumps move water through the system, control valves
allow water pressure and flow direction to be regulat-
ed, and storage facilities  such as reservoirs  and tanks
smooth out the  effects of fluctuating demands (flow
equalization).  Storage facilities  also provide reserve
capacity for fire suppression and other emergencies.
Generally, pumping operations are optimized based on
cost of electricity and  demand requirements.  A utility
might consider operational changes based on overrid-
ing demand type in an attempt to minimize water age.
For example, a storage tank might normally be cycled
to only 50 percent of its capacity because of fire-fight-
ing needs. The utility  could consider a change in strat-
egy in which it cycles the tank to utilize 65 percent of
its capacity  and  then  make arrangements to  meet the
additional 15 percent  fire-fighting demand from alter-
nate sources such as other tanks,  or even the purchase
of bulk water from  a nearby utility.

7.1.3 Changing Disinfectants
If DBF formation or nitrification is a problem, the util-
ity could consider switching disinfectants on a periodic
or permanent basis. For example, a drinking water util-
ity that normally uses chloramines might temporarily
switch to  free chlorine as a preventative nitrification
control measure. This switch to chlorination would be
accomplished system-wide by simply turning off the
ammonia feed facilities.  However,  to  switch to free
chlorine in an isolated pressure zone or storage facil-
ity, enough chlorine must be added to exceed the break-
point  and thereby achieve a free  chlorine residual.  If
strategies such as adjustments in chlorine to ammonia
ratio,  increased turnover, or flushing have not solved
the problem, breakpoint  chlorination is a commonly
utilized approach in storage tanks.

Utilities that normally  chlorinate could consider a tem-
porary switch to chloramines. Recently, many utilities
have  switched from chlorine to chloramines  because
chloramines are more stable and associated DBF forma-
tion is lower. Whether disinfectant changes are long- or
short-term, utilities should be aware that these changes
may have implications for protecting public health, es-
pecially during an intrusion event. Chloramine is a less
powerful disinfectant  than chlorine and may be inad-
equate for protection against microorganisms  entering
the distribution system. Giardia cysts and enteric viruses
are known to be  less easily inactivated by chloramines
than chlorine. However, any significant intrusion event

    will likely overwhelm either types of residual disin-
    fectant.  In addition, the utility should inform dialysis
    centers that chloramines are being used so that they can
    have their water treatment system enhanced to remove
    chloramine. In addition to chloramines, other substanc-
    es found in tap water can also interfere with dialysis.
    For example, copper, fluoride, sulfate, nitrate, zinc and
    aluminum also impact dialysis operations.  Remember,
    chlorine and chloramines are both toxic to fish.  Gener-
    ally, the operators of dialysis centers and fish breeders
    know that disinfectants in tap water must be removed
    before being used in their facilities.  Therefore, utilities
    changing disinfectant techniques must notify the public
    of the change, contact kidney dialysis facilities, and fish
    breeders. Disinfection changes may  also cause a change
    in pH levels in a distribution system resulting in tempo-
    rarily elevated lead or copper levels.

    7.1.4 Implementing Corrosion  Control
    Corrosion in drinking water systems can  be control-
    led by adjusting  pH, alkalinity  or by introducing
    corrosion inhibitors.  Increase  in pH is  one of the
    effective methods for reducing lead and copper cor-
    rosion.  According to research studies, the optimal
    pH for lead and copper control falls between 7.5 and
    9.5 (the value depends upon the system and inhibitor

Changing Disinfectants (AwwaRF, 2006b)
In November 2003, the American Water Works Asso-
ciation  Research Foundation (AwwaRF)  sponsored a
project to evaluate the long-term effects of disinfection
changes on distribution system water  quality. The re-
search team evaluated 19 utilities that had changed their
primary and/or secondary disinfectants.   Specifically,
seven utilities changed from  chlorine to chloramines,
six changed from chlorine to ozone, two changed from
chlorine to chlorine dioxide,  two changed from  chlo-
rine to ultraviolet disinfection, and  two added booster
chlorination.  The study concluded that, in general, the
results were positive.  The following specific  improve-
ments in the distribution system water quality were ob-
served as a result of changing disinfectants:
   •  Better microbial quality - lower coliform levels
     and heterotrophic plate counts
   •  Lower DBFs - reduced levels of trihalomethanes
     and haloacetic acids
   •  Reduced numbers of customer complaints
     regarding red water or discolored water
   •  Reduced numbers of customer complaints
     regarding tastes and odors
Despite the positive effects of changing  disinfectants,
there was one participating utility that experienced an
increase in lead levels. Therefore, a utility should care-
fully evaluate the effect of making such changes.
   Mommy, I cleaned the fish
   bowl and filled it with tap
 water.  Nobody told me using
  tap water with disinfectants
      would kill my fish!
used). The higher pH level can also help reduce iron
concentrations.  However, high pH can also result in
precipitation and scale on the pipe that significantly
impact the hydraulics of a distribution system.

Increasing alkalinity can also assist in corrosion con-
trol, and the optimal alkalinity for lead and copper
control lies between 25 and 75 mg/L as calcium car-
bonate.  Higher alkalinity levels (>60 mg/L as calcium
carbonate) are favorable for controlling iron corrosion
and result in better buffer intensity, which in turn pro-
vides a stable pH.

Phosphate- and silicate-based corrosion inhibitors are
often used by water utilities.   The most  commonly
used  inhibitors  include orthophosphate,  polyphos-
phate and sodium silicate, with or without zinc. Or-
thophosphate and zinc orthophosphate have reported-
ly been successful in reducing lead and copper levels;
polyphosphates are reported to prevent iron corrosion.
Sodium silicate  has  been shown  to reduce  lead and
copper levels. It should be noted  that sodium silicate
is basic and always results in pH increases.  Therefore,
it is difficult to determine if reductions in lead or cop-
per are due to the use of sodium silicate or higher pH
levels. Nevertheless, sodium silicate has been shown
to be an effective inhibitor.  Utilities using inhibitors
should periodically monitor the inhibitor concentra-
tion within the distribution system.

Use  of corrosion inhibitors and pH and/or alkalinity
adjustments to control lead, copper and/or iron levels
in drinking water should be employed with caution.
Pilot studies should be conducted  to determine the ef-
fectiveness of a specific control method.

      7.1.5 Preventing Sedimentation and Scale
      Under low velocity conditions, suspended solids may
      deposit on the pipe surface. Scale and mineral deposits
      may accumulate on pipe surfaces if the mineral content
      in the water is high and the pH/alkalinity of the water
      is supportive of scale formation  (as addressed previ-
      ously in Section 5.5). The accumulated sediment and
      scale reduces the carrying capacity of the pipe and can
      also create a more favorable environment for microbial
      growth.  Although sediments and  scales themselves do
      not necessarily pose a serious health risk, they can cause
      water quality deterioration, taste and odor problems, or
      discoloration.  Furthermore, the deposited solids may
      be re-suspended by sudden changes in flow. Significant
      changes in flow (velocity and direction) can scour sedi-
      ments, tubercles, and scale deposits from pipe walls and
      result in degradation of water quality. It is possible that
      these re-suspended particles may contain adsorbed con-
      taminants such as arsenic and other metals that origi-
      nated in the source water.  Rapid changes in velocity
      and flow direction can occur during main breaks, when
      service reservoirs are being  filled  or  drained, when
      pumps are going on or offline, or  during hydrant flush-
      ing activities.

      As metal pipes corrode, roughness tends to increase,
      and cross-sectional area tends to  decrease.  Microbial
      slimes can also result in a decrease in the hydraulic car-
      rying capacity of water mains. This loss in carrying
      capacity can result in a water system that cannot deliver
      necessary fire flow. Increases in pumping rates may be
      necessary to overcome the increasing friction losses and
      local deficiencies in system pressure. These increased
      pumping requirements can overload motors and result
      in a significant increase in energy consumption, and in
      operating and maintenance costs.  Furthermore, the ad-
      ditional pressure can over-pressurize weaker portions
      of the distribution system, potentially increasing the
      number of leaks and breaks.  To  avoid these negative
      consequences, utilities should  operate their distribu-
      tion systems in a manner that minimizes sedimentation
      and scaling by maintaining appropriate flow and water
      chemistry (e.g.,  pH and alkalinity  levels) throughout
      the distribution system.

      7.1.6 Implementing a Flushing  Program
      Flushing  involves moving water through  the distri-
      bution system at a high rate, and then  discharging it
      through  hydrants or blow-off ports. A flushing pro-
      gram is designed with one or more  specific objectives
      such as replacing aged water, removing loose deposits
      and sediments, and/or scouring internal  pipe surfaces.
      Utilities typically implement a flushing program in re-
      sponse to consumer complaints. Terms such as "direc-
      tional flushing" or "unidirectional flushing" are used to
describe the operation of valves during a flushing pro-
gram to maximize velocity and control flow direction,
starting with the largest mains and moving to the small-
est. Flushing is usually accomplished by  opening one
or more hydrants in a planned pattern. A  good rule of
thumb for flushing is to start at the location with "best"
water quality in the system and move outwards.

Residual disinfectant  concentration in a  distribution
system can be reestablished or stabilized by displacing
"old" water and replacing it with fresh water containing
a measurable residual disinfectant.  Flushing can also
remedy or prevent nitrification in systems that utilize
chloramines for disinfection.  Water that  has elevated
levels of ammonia is replaced with water containing a
higher disinfectant residual. However, flushing is not
required by all state agencies. Of 34 states responding
to a survey by the Association of State Drinking Water
Administrators, only 11 require flushing/cleaning/pig-
ging, with 20 others encouraging the practice.
   The new prototype pressurized flush system
   SP17 flushes pipes up to 1,000 feet long.
   We could save thousands of gallons of water
      during routine flushing operations.
  Flushing Velocities (AwwaRF, 2004b)
  AwwaRF sponsored a project to evaluate a range of site-
  specific flushing velocities. The study report indicates that
  utilities which had previously never flushed their systems
  benefited significantly from a high velocity (~5 feet per
  second [fps]) unidirectional  flushing program.  Utilities
  that had flushed within the last 4 to 6 years could receive
  approximately the same benefit (and save water) by flush-
  ing at a lower velocity (2 to  4 fps).  The AwwaRF study
  also determined that loose particles, including corrosion
  particles, iron sludge, sand,  and iron floe, are removed
  from smooth or slightly tuberculated pipes at lower flush-
  ing velocities (2 to 4 fps). In most cases, distribution sys-
  tem lines should be flushed until the water is clear.

Some systems may choose to clean pipelines that are
suspected of contributing to  the decay of disinfectant
residuals in finished water. A variety of cleaning meth-
ods are available which include:

   •   swabbing

   •   scraping

   •   pigging

   •   chemical cleaning, and

   •   jet flowing

Swabbing, scraping, and pigging refer to methods that
remove scale and deposits from the inside of the pipes.
Chemical cleaning involves the injection of chemi-
cal cleaners. Jet flowing uses a high-pressure method
to wash the  inside of the pipe. Each technique has its
benefits and disadvantages and should be tailored to a
specific site. In addition, depending upon the age of the
pipes, some  utilities may want to consider pipe lining
or replacement.

7.1.7 Infrastructure Replacement and/or
      Treatment Upgrades
Proper treatment methods, tailored to the utility's source
water characteristics, can also solve potential problems
in the distribution system. If optimum treatment is em-
ployed, it can greatly improve the biochemical stability
of the finished water.  Biochemical stability is closely
related to the amount and kind of organic matter present
in the water. Problems associated with the formation of
DBFs increase with the amount of organic matter left
in the water. Treatment to remove organics, inorganics,
and turbidity will also curb chlorine decay. The most ef-
fective treatment methods for maintaining biochemical
stability include:

   •   enhanced coagulation

   •   biological filtration

   •   ultrafiltration/nanofiltration

   •   granular activated carbon treatment

Water main breaks commonly occur in older or in poor-
ly designed  systems.  Main breaks are disruptive and
expensive to fix.  Furthermore,  for rusting and aging
pipes and finished water storage facilities, replacement
may be the only viable option. Therefore, utility opera-
tors and managers must develop a long-term strategy
for timely maintenance and replacement.   However,
these types of infrastructure replacement and treatment
upgrade projects require a significant  amount of finan-
cial resources  and time.  Possible financial strategies
designed to accomplish these goals are discussed in the
next section of this document.
7.2  Financial Strategies
Small- and medium-sized systems  face unique finan-
cial challenges because they cannot take advantage of
the economies of scale associated with larger drinking
water systems. For example, in a small system, a piece
of equipment costing $1,000 may be spread over a cus-
tomer base of 100 to 1,000 customers.  In a larger sys-
tem, the cost of this same piece of equipment may be
spread over 10,000 to 100,000 customers.  Simply put,
any capital investment for smaller systems is generally
higher on a per customer basis or per capita basis than
in a larger system.

  Financial Strategy (EPA - EFAB, 2005)
  In rural and developing areas, back-end loading could be
  used in financing water projects where hook-up fees  and
  user charges only begin to flow after a project is complet-
  ed. Infrastructure projects in such areas are often judged
  unaffordable because the debt associated  with the capital
  investment needed for new facilities cannot be immediate-
  ly serviced by user charges. In fact, new hook-ups/connec-
  tions often occur slowly. As connections are made and the
  service area rate base increases, user charge revenues grow
  to support debt repayment. Back-end loading can enable
  projects to proceed because it solves immediate environ-
  mental needs by deferring financial issues of "affordabil-
  ity" of debt repayment to a later time.

  This approach  has proven to be valuable  for San Benito,
  Texas, along the US-Mexican border. The North American
  Development Bank guaranteed a bond issue for San Benito
  with a highly skewed amortization schedule that allowed
  for the build-out of the system and the build-up of oper-
  ating revenues  to sustain long-term debt service. In  this
  case, the new water system would enjoy the very low inter-
  est rates provided by the bank guaranty until such time as
  the system revenues could provide substantial debt service
In cases  where the price of water cannot be simply
passed on to the customer, small- and medium-sized
utilities can apply for grants and low-interest loans.  A
grant is a form of financial assistance that is given to a
utility which does not have to be repaid. Loans must be
repaid along with the appropriate interest. These terms
are defined more carefully in the following paragraphs:

   •   Grant Programs: Grants are generally awarded
      to states, local governments or other nonprofit
      organizations. The primary advantage of grants
      is that the recipients do not have to use their
      own resources to pay the costs that the grant
      covers. Applying for grants, however, can
      require a significant commitment of time by
      utility personnel.  In addition, the availability

  Sustainable Pricing (EPA, 2005b)
  Individual customers are the most important source of rev-
  enue for a drinking water system.  The income provided
  by customers is critical to ensuring that systems are op-
  erated properly and efficiently both in the present and in
  the future.  Charging customers the actual cost of service
  ensures that water systems guarantee themselves a stable
  source of funds that is sufficient to cover the cost of opera-
  tion (including treatment, storage, and distribution costs).
  This policy also allows for the acquisition of funds for in-
  frastructure investments.  Asking  customers to pay for a
  commodity or service  sends  a signal about the value of
  the product or service they are purchasing.  Fees and other
  charges that reflect the full cost of water service help cus-
  tomers recognize  the value of water service.  Customers
  also become more aware of how much water they use and
  how they use it. To support this approach, EPA has devel-
  oped a sustainable infrastructure initiative which is based
  on the following four pillars:

     •  Better Management - Similar to asset management,
       environmental management systems, consolidation,
       and public-private partnerships can offer significant
       savings for small water utilities.

     •  Full-Cost Pricing - A key consideration in
       constructing, operating, and maintaining
       infrastructure is ensuring that there are sufficient
       revenues in place to support the costs of doing
       business. Sensible pricing can also have the added
       benefit of encouraging efficient water use.

     •  Efficient Water Use - One way to reduce the
       need for costly infrastructure is efficient use of
       water. There are many options for enhancing
       water efficiency including metering, water reuse,
       water-saving appliances, landscaping, and public

     •  Watershed Approaches to Protection - In
       addressing infrastructure needs for the purposes
       of water supply and water quality, it is important
       to look at water resources in a coordinated way.
       Directing resources towards high priorities, such as
       permitting on a watershed basis, and water quality
       trading are all means of ensuring that investments
       achieve the  greatest benefit.

            and timing of the grant award may not match
            the utility's needs.  Most grant programs have
            limited funds, and usually there is significant
            competition for this type of funding. Grants also
            have project eligibility requirements, and some
            programs may specify that the grantee contribute
            a share of the total project funds.
                       x	x.
                        I have solved our financial crisis,N
                          here is a "cash cow" and a
                       "goose that lays the golden egg!"
            Loan Programs: Loans are available from
            governments, banks or other financial
      institutions and the application process can be
      relatively quick. Commercial interest rates are
      generally higher with less favorable pay back
      rules than government loans. State programs
      generally have better rates and terms for those
      systems that do not qualify for conventional
      types of financing.  The terms of loans vary
      significantly and the utility should carefully
      evaluate these terms before a loan is secured.

Some of these financial options (both grants and loans)
are briefly summarized in the following sections.

Congress established the Drinking Water State Revolv-
ing Fund (DWSRF) as part of the 1996 SDWA Amend-
ments to provide states with a financing mechanism to
ensure safe drinking water for the public. EPA, through
the various state agencies, administers  the DWSRF in
order to provide financial resources to upgrade and re-
place drinking water infrastructure.  PWSs can receive
loans with very low or zero percent interest rates with
repayment periods of up to 20 years. However, in some
cases, drinking water utilities in disadvantaged commu-
nities may find even low-interest loans unaffordable. In
these types of cases, states can provide DWSRF funds
at a negative interest loan rate, or under a principal for-
giveness loan with an extended repayment period of up
to 30 years. Each state has specific eligibility criteria to
determine funding priorities. Funding requests under
the DWSRF program are allocated based on the follow-
ing order of priority:

   •   Requests  that address the most serious health
      risks to consumers

   •   Requests  necessary to comply with  SDWA

Creative Funding (Hudson, 2007)
Recent SDWA revisions to reduce the Arsenic Maximum
Contaminant Level (MCL) to 0.010 mg/L affected approx-
imately 80 small Indiana PWSs.  As a result, many small
utilities needed assistance to comply with the new stand-
ard.  A majority of these affected systems were rural (serv-
ing fewer than 500 people) and the Indiana DWSRF Loan
Program estimated that  the average arsenic remediation
project would cost $44,000. Unfortunately, this amount
was too small to justify a DWSRF loan.  If a utility cannot
justify a project under the DWSPJ7, these funds cannot be
used for small systems. To solve this problem, the Indiana
DWSPJ7 created the Arsenic Remediation Grant Program
in May 2006.  By combining DWSRF set-aside funds for
planning and design costs and  state monies for construc-
tion  costs,  the DWSRF  Loan Program was  able to offer
grants up to $100,000 to small PWSs to cover the entire
cost of arsenic remediation projects.

       •  Requests that assist water systems which are
          most in need, on a per-household basis (as
          determined by the state affordability criteria)

     Similar funding assistance is also  available to Indian
     tribes in the U.S.

     7.2.2 Community Development Block Grants
     The U.S. Department of Housing and Urban Develop-
     ment administers a Community Development Block
     Grant (CDBG) program through the individual states.
     The program provides small communities  with re-
     sources to address a wide range  of needs. The program
     gives each state the opportunity to administer CDBG
     funds for "non-entitlement areas."  Generally speaking,
  I received your application for loan, I
  am afraid we need more information
  than what you currently have provided
   for us to process this application.
"non-entitlement areas" are cities with populations of
less than 50,000 and counties with populations of less
than 200,000.   The primary objective of this CDBG
program is to develop viable communities by providing
decent housing and a suitable living environment. This
general  objective is achieved by prioritizing activities
which benefit low-  and moderate-income families or
aid in the prevention or elimination of slums or blight.
Under unique circumstances, states may also use their
funds to meet urgent community development needs.
A need  is considered urgent if it poses a serious and
immediate threat to the health or welfare of the com-
munity  and  has arisen in the past 18 months.  Local
governments have the responsibility  to consider local
needs, prepare grant applications for  submission to the
state, and carry out the funded community development
activities.  The list of eligible activities under this pro-
gram includes construction or reconstruction of water
and sewer facilities.

7.2.3 Rural Utilities System
One  of the six basic mission areas of the U.S. Depart-
ment of Agriculture (USDA) is the Rural Utilities Sys-
tem (RUS).  Under the RUS umbrella, USDA provides
a variety of water loan and grant programs. Along with
EPA and other federal agencies, USDA supports organ-
izations such as the National Rural Water Association
(NRWA) and the Rural Community Assistance Partner-
ship.  The USDA's RUS issues contracts to NRWA for
providing rural water circuit rider technical assistance.
In addition to supporting these national organizations,
USDA provides emergency  community  water assist-
ance grants to rural communities that have experienced
a significant decline in the quantity or quality of drink-
ing water. Grants  are provided to rural areas and cities
or towns with low income and a population of fewer
than 10,000.  Grants can cover up to  100 percent of
project costs. The maximum grant is $500,000 when
a significant decline in quantity or quality of water oc-
curred within two years, or up to $150,000, to make
emergency repairs and replace facilities in existing sys-

7.2.4 Economic Development Administration
The  U.S.  Department of Commerce provides grants
through the  Economic Development Administration's
(EDA) Public Works and Development Program.  Ap-
plications must be submitted to the state economic de-
velopment agency; states are authorized to administer
the funds. A drinking water project must be located in
a community or county determined to be economically
distressed, and the project must be directly related to
future economic development. Some restrictions apply
when grants are provided in conjunction with other fi-
nancial assistance.  The combined funding is generally
limited to 80 percent of the total project cost.

      7.2.5 Other Entities and Private Foundations
      Appalachian Regional Commission (ARC) ARC sup-
      ports qualifying applicants in the designated Appalachi-
      an Regions of 13 states.  The ARC's local development
      districts provide assistance in preparing an applicant's
      proposal.  Priority funding is determined each year by
      the  state  governors, Appalachian  district personnel,
      and ARC members. All projects that qualify for grant
      funding must be directly related to economic develop-
      ment, housing development, or downtown revitalization
      and improvement.  Drinking water projects are among
      the types of projects eligible for assistance.   It should
      be noted that ARC grants are limited to 50 percent of
      project costs and require the  recipients to supply the
      other 50 percent.  An exception is made for economi-
      cally distressed counties, which can receive 80 percent
      and must supply only 20 percent. To raise the remain-
      ing 20 percent of funds, owners of small systems in dis-
      tressed counties should innovatively and  aggressively
      seek other sources of funding.

      Indian Health Service (IHS) IHS is a part of the De-
      partment of Health and Human Services, and provides
      grants for projects undertaken by American Indians and
      Alaska Natives.  In 1959, Congress passed the Indian
      Sanitation Facilities Act to provide improved health
      conditions by improving sanitation, sewer, solid waste,
      and drinking water facilities. IHS grants support public
      health rather than economic development or environ-
      mental preservation and do not include funding for op-
      eration and maintenance. No  matching funds are nec-
      essary, and IHS grants  can be consolidated with those
      from other agencies.

      Small Community Water  Infrastructure Exchange
      (SCWIE) SCWIE is a network of water funding offi-
      cials. Under the auspices of the Council of Infrastruc-
      ture  Financing Authorities, a group of public and non-
      profit environmental funding  and technical  assistance
      officials combined their efforts to create SCWIE.

      Private Foundations Private  foundations are another
      possible source of funding for small- and medium-sized
      PWSs. These are often overlooked by small PWS man-
      agers. Information about smaller foundations can be ob-
      tained from a local Internal Revenue Service (IRS) of-
      fice.  The IRS annually collects Form 990-PF (Return on
      Private Foundations) from foundations of all sizes, and
      compiles information about the foundations' interests,
      restrictions, application procedures, and deadlines.

      7.3 Management Strategies
      If the operational and financial strategies currently avail-
      able  to a utility do not  have long-term sustainability, a
      utility should consider  management and institutional
      changes. Some options to consider are merging with a
                    Additional Information
  More information on the DWSRF is available at: http://
  More information on state  CDBGs is available at: http://
  More information on RUS assistance is available at: http://
  More information on EDA assistance is available at:
  http ://www. eda. gov/InvestmentsGrants/Investments. xml
  More information on ARC assistance is available at: http://
  www.arc.gov/index.do ?nodeld=101
  More information on IHS assistance is available at: http://
  More information on SCWIE assistance is available  at:
  http ://www. scwie.org/ContactSearch. asp
  A commercial  source of private foundation listing online
  is: http://foundationcenter.org/

larger utility, or changing ownership and/or management
of the water utility (from private to public or vice versa).

7.3.1 Small Systems Working Together
In general, state and federal regulatory agencies encour-
age small water  systems to work together if it makes
financial  sense. Working together generally  results in
a regulatory  agency having more effective control over
water quality and regional  development.  Furthermore,
the economies of scale associated with working together
tend to ensure the long-term financial viability of a sys-
tem.  One challenge in working together is the difficulty
in servicing a geographically diverse distribution system
from a central  location. In  such cases, remote monitor-
ing and reporting is recommended to ensure prompt local
service even if bulk water is purchased from a larger util-
ity.  Each manager of a small- and medium-sized utility
should consider the pros and  cons of working together,
for developing  regional water  usage rates and/or central-
ized purchasing.  In addition to concerns of financial via-
bility, managers should consider the geographical spread
and type  of source water of the combined systems. The
number one  concern of the partners  is the potential im-
pact of the combination on the quality of the water served
to the consumer. Again, remote monitoring and reporting
is recommended to ensure the quality of the water in the
combined distribution system. EPA's Community Water
System Survey, conducted in the year 2000, indicated
that there was a continued decline in the number of sys-
tems serving fewer than 3,300 people, while the number
serving more than 3,300 people grew by 20 percent.

Utility Merger (KEPPC, 2006)
The  Northern Kentucky Water  District  (NKWD)  was
formed  in  1997 from  the merger of water districts in
Kenton and Campbell counties. In recent years, it has also
acquired the Newport and Taylor Mill water utilities. By
2006, NKWD had 78,000 retail  customers in Campbell
and Kenton counties and provided wholesale water service
to the Pendleton County, Bullock Pen water districts, and
to the city of Walton.
In 2003, the Kentucky Public Service Commission granted
NKWD a rate adjustment that equalized the water rates in
the former Kenton and Campbell county districts. In 2004,
PSC granted rate  adjustments to equalize water rates in
Newport with the rest of the  district.  In 2006, the PSC
granted a rate adjustment to equalize the rates for custom-
ers in Taylor Mill.  The 2006 rate increase was estimated to
raise the quarterly bill for the average NKWD residential
customer consuming 18,000 gallons/quarter, from $78.65
to $83.70 (an increase of $5.02, or 6.4 percent).  It is es-
timated that the 2006 rate increase will increase NKWD's
annual revenues from water sales by 6.8 percent, to $36.3
    7.3.2 Change in Ownership and/or
    In general, there are  four options to consider when
    changing ownership and/or management of water utili-
    ties including:

       •   Efficiency Improvement Program: Implementing
          operational and management changes to improve

       •   Municipalization: The assets, operations
          and ownership of private water systems are
          transferred to a public entity.

       •   Privatization:  The assets, operations, and
          ownership are transferred to a private entity

       •   Public-Private Partnership:  In general, the
          public retains the ownership and control
          of the system, but privatizes operation and

    Private utilities are generally perceived as being profit-
    oriented and  hence more efficient than public  or mu-
    nicipal  utilities.  Because they are for-profit entities
    there is  a perception that they may fail to invest in long-
    term growth  which may lead to  poor system mainte-
    nance and upgrade practices. Municipalities, because
    they are non-profit entities and represent the people, are
    perceived as  likely to invest in the system and have a
    plan for long-term growth. On the other hand, because
    municipal systems are non-profit entities, there is con-
cern that there are inefficiencies built into the system
which may increase costs to the consumer. The general
perception about public-private partnerships is that they
represent the "best" of both municipal and private sys-
tems.  These perceptions are  generally anecdotal and
based on individual cases where information is avail-
able.  There are no long-term data or analyses that con-
clusively support any of these general perceptions.
            7.4 SmallWater USA -
                 Cell Tower Installation
Problem #1 Water Storage Tank Antenna
Several telephone companies approached SmallWater,
USA officials and made financial offers to the town if
they were permitted to install cell phone antennas on the
top of the elevated tank in the northern part of the water
system. It sounded like a good source of needed funds
but the official wanted to make sure that there would
not be any problems. He talked to an engineering firm
that specialized in tank construction and maintenance
procedures. Following is a summary of the information
that he received from the engineer.

Issues to Consider
The rapid expansion of wireless communication serv-
ices throughout the United States has resulted in the
construction of many cellular antenna towers. To  save
on the cost of erecting these towers, communications
companies look for existing structures that are suitable
for locating their antennas. Also, in some areas, zoning
restrictions have severely limited the ability of cellular
companies to locate their towers. For these reasons, wa-
ter storage tanks are prime sites for antennas. Existing
tanks are often the highest structure in a community and
usually have pre-existing Federal Aviation Authority
and zoning approvals.

Leasing revenue from  antenna installations has been
a welcome development for hard-pressed water utility
budgets. Leasing rates range from a few hundred dollars
to over $ 1,000 per month depending on the location and
suitability of the storage tank. Since tanks usually  have
room for multiple antenna installations, leasing revenue
can be doubled or tripled by adding cellular carriers.
In some cases, it is possible to pay for all future  tank
maintenance and painting with these revenues.  While
the income provided to water utilities from placement
of antennas is certainly worth considering, care must be
taken to avoid the adverse effects of these installations.

Guidance (Source: Cabin, I.M., 2007)
Many problems  have occurred from antenna installa-
tions that were improperly  designed and constructed.
Many installers have viewed the tank as simply a  plat-

      form for their antennas, without understanding the im-
      portant function that the tank serves and the purpose of
      tank appurtenances. Problem areas include:

         1.  Structural damage

         2.  Coating and corrosion damage

         3.  Occupational Safety and Health Administration
            (OSHA) violations

         4.  Restriction of access to ladders, manholes and
            hatches with resultant confined space and safety

         5.  Contamination of water supply through
            improperly sealed penetrations

         6.  Potential  for interference with future painting

         7.  Poor aesthetic appearance

      A few basic steps should be followed by storage tank
      owners to avoid these problems. First, the  cellular
      company should be required to provide a drawing of
      its complete installation including site utilities, ground
      structures, equipment panels, cable routing, and anten-
      na structures. Secondly, a qualified engineering firm ex-
      perienced with both storage tanks and antenna installa-
      tions should be  retained to inspect the tank, and review
      the drawings, welding procedures and coating repair
      specifications. Structural analysis should be performed
      to ensure that the tank can safely support the antennas.
      Also, care must be taken that the new installation does
      not interfere with existing cellular or utility antennas.

      Only after all necessary drawing and specification revi-
      sions are completed should the installer be allowed to
      begin. Keys to the tank or tank site should be returned
      when the project is finished. It is not recommended that
      antenna  companies be allowed to access the  tank to
      service their equipment without utility personnel pro-
      viding authorization and access.

      The final step is inspection of the completed installa-
      tion. The same  firm that reviewed the drawings should
      inspect the entire installation including the interior paint
      repairs.  In some cases, paint repairs  can only be com-
      pleted during low demand times of the year.  In other
      cases,  the repairs must wait for warmer weather. This
      will require coordination with the cellular company to
      ensure that the interior paint is properly repaired.

      When negotiating a lease with the cellular company, the
      design review and inspection services should be includ-
      ed in the contract at the company's expense. Most cel-
      lular companies are very cooperative in including these
      services  in the lease. It is a minimal expense and also
      provides them with the assurance that their equipment
will be properly installed. A number of other legal and
financial considerations should be carefully  evaluated
including length of contract, cost of living adjustments,
access, liability, exclusivity clauses, and future painting
expenses. Since many utilities already have antenna in-
stallations, it would be worthwhile to inquire about their
leases and hopefully benefit from their experience.

Water storage tank antennas are certainly worth investi-
gating. By following these steps, one should be able to
obtain the benefit of this new source of revenue while
avoiding the problems that can be caused by deficient an-
tenna design and installation. Figures 7.1 and 7.2 show
pictures of bad and good cell-tower designs, respective-
ly. The crowded design shown in Figure 7.1 could lead
to operational, maintenance and structural problems.

Problem #2 Operational Changes to Reduce
      Water Quality Degradation in Storage
During the past summer,  SmallWater, USA officials
received frequent taste and odor complaints from resi-
dents in the trailer park located near the old standpipe.
Discussions with the town  consulting engineer led to
the likely conclusion that these taste and odor problems
were probably due to  water quality degradation in the
standpipe. Some options for dealing with this problem
were discussed and will be tried out next summer.

Issues to Consider
Because  water  sometimes  spends a large amount of
time in a storage  tank, it is susceptible to degradation
of water quality. Some specific forms of water quality
degradation can include: loss of disinfectant residual,
regrowth of bacteria, formation of DBFs, nitrification
and sedimentation. In all of these phenomena, the deg-
radation is associated with two physical processes in a
tank: aging of water and mixing within the tank.

Since it is not uncommon for water to  spend several
days or sometimes  even weeks  in a storage facility,
tanks are prime candidates  for potential water quality
problems. There is no fixed standard for allowable wa-
ter age, but some experts suggest that 3 to 5  days is a
reasonable maximum residence time within a  tank. Al-
lowable water age varies based on the chemical content
of the water and the type of disinfectant that is utilized.
An  approximate value for the average residence time
can be easily calculated based on the turnover within
the tank using the following equation:

          Average Residence time (days) =
      Average water volume in tank (gallons) -^
       Average daily inflow (gallons per day)

Figure 7.1 Crowded Cell Tower Installation
encourage good mixing - namely, the water that is en-
tering the tank during the fill cycle should mix well with
the water that is already in the tank.  A poorly mixed
tank can result in zones or pockets of older, deteriorated
water. In some  cases,  the tank may become  stratified
(poor vertical mixing), primarily when the inflow water
is colder than the water in the tank. Tall tanks, such as
the SmallWater, USA standpipe, are especially suscep-
tible to mixing and stratification problems.  Good mix-
ing will generally occur if 1) the inflow "jet" enters at
a relatively high velocity (at least 1 foot per second), 2)
the inlet is oriented to encourage mixing with the water
in the tank, 3) the water level in the tank is allowed to
fluctuate over a range of several feet over the course of
each day, and 4) the water temperature of the inflow is
approximately the same as the temperature of the water
in the tank. The average inflow velocity for the stand-
pipe was calculated by dividing the average inflow rate
(100 gpm) by the  cross-sectional  area of the 16-inch
inlet. This showed a typical inflow velocity of only 0.16
feet per second (fps) - far less than the  recommended
velocity of 1 fps.

Based on this analysis, the engineer suggested that no
modification in operations was needed  but that some
minor modifications in the standpipe inlet configura-
tion should be made. The primary recommendation was
that a "reducer" be placed on the inlet-outlet line where
it entered  the standpipe  so that the effective  diameter
would be reduced from 16 to 6 inches. Other situations
may require the addition of more complex inlet-outlet
designs  or the use of mechanical mixers to encourage
circulation in the tank. There are a variety of modeling
and monitoring procedures  that can be  used to assess
whether there are mixing problems in a tank and to test
alternative schemes for improving mixing in a tank.
Figure 7.2 A Well-Designed and Constructed Cell
Tower Installation
      The standpipe typically contains about 150,000 gallons
      of water. Based on Supervisory Control and Data Ac-
      quisition (SCADA) records, the daily inflow is about
      75,000 gallons per day. Using this equation, the aver-
      age residence time in the standpipe was calculated as
      150,000 - 75,000 = 2 days. This was considered to be

      Mixing is another issue in tank operation and design.
      Distribution system storage tanks should be designed to

          Operational, Financial, and Management
              Strategies to Address Distribution
                  System Water Quality Issues
    4 Type of disinfectant that can be more toxic to
    5 Financial assistance that must be repaid with
      the applicable interest
    7 Financial assistance that does not have to be
      paid  back
    8 Commonly used base-chemical for corrosion
1  Acronym for EPA-established financing
2  Term for a publicly-owned non-profit water
3  Common procedure for removing loose
  sediments and deposits in pipes
6  Reduce "this" in distribution system to
  control DBP formation
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Chapter  8
The references included in this bibliography contain
additional detailed information for readers who wish to
pursue, in greater detail, the specific topics discussed
in this guide. Many of these references (especially the
EPA references) are freely available on the Internet.
The references are listed alphabetically, based on
the last name of the first author(s). In cases where
there are two or more works by the same author (e.g.,
AWWA, AwwaRF, and EPA), the entries  are listed by
the year, with the most recent document listed first.
The reverse chronological order makes it easy for the
reader to look up the most recent publication first.

American Society of Civil Engineers (ASCE).
"Report Card for America's Infrastructure, Drinking
Water," ASCE, Reston, Virginia.  2005.

American Water Works Association (AWWA).  Field
Guide to SDWA Regulations. Technical Editors
- Lauer, W.C., Scharfenaker, M. and J.M. Stubbart.
Published by AWWA,  Denver, Colorado. 2006a.

AWWA. M33 Manual of Water Supply Practices
"Flowmeters in Water  Supply."  Second Edition.
Published by AWWA,  Denver, Colorado. 2006b.

AWWA. AWWA Water Operator Field Guide.
Published by AWWA,  Denver, Colorado. 2004.

AWWA. M31 Distribution System Requirements for
Fire Protection, Third Edition. Published by AWWA,
Denver, Colorado. 1999.

American Water Works Association Research
Foundation (AwwaRF). Asset Management Planning
and Reporting Options for Water Utilities. 2006a.

AwwaRF. Long-Term Effects of Disinfection Changes
on Water Quality. 2006b.

AwwaRF. Development of Distribution System Water
Quality Optimization Plans. 2005.

AwwaRF. External Corrosion and Corrosion Control
of Buried Water Mains. 2004a.

AwwaRF. Establishing Site-Specific Flushing
Velocities. 2004b.

Bhardwaj,V Pumps-A Tech Brief. Published by the Na-
tional Drinking Water Clearinghouse at the West Virginia
University, Morgantown, West Virginia. Summer 2003.
Bhardwaj, V Reservoirs, Towers, and Tanks: Drinking
Water Storage Facilities - A Tech Brief. Published by
the National Drinking Water Clearinghouse at the West
Virginia University, Morgantown, West Virginia. Fall

Bowman, L. Comparison of Water and Wastewater
System Financing through the Rural Utilities Service
and State Revolving Funds. Published by National Rural
Water Association (NRWA), Duncan, Oklahoma. 2004.

Braden, J.B., Lee, M.Y., Jaffe, M. Building Technical,
Financial, and Managerial Capacity for Small Water
Systems: The Role of Consolidation, Partnership,
and Other Organizational Innovations. Published
by Midwest Technology Assistance Center (MTAC)
for Small Public Water Systems. MTAC Publication
TR07-01. Undated.

Brenda, L. Water System Operator's Guide. Published
by the U.S. Department of Agriculture (USDA)
Forest Service - National Technology & Development
Program. Publication ID: 0623 1802- SanDimas
Technology and Development Center (SDTDC). June

California Department of Health Services (CDHS)
and Environmental Protection Agency (EPA).  Small
Water System Operation and Maintenance - A Field
Study Training Program. Fourth Edition. Published by
California State University, Sacramento Foundation.

Canadian Federal-Provincial-Territorial Committee on
Drinking Water. Corrosion Control in Drinking Water
Distribution Systems.  Document prepared for Public
Comment. April 2007.

Clark, R.M., E.E. Geldreich, K.R. Fox, E.W Rice,
C.H. Johnson, J.A. Goodrich, J.A. Barnick, F.
Abdesaken, J.E. Hill and FJ. Angulo. A waterborne
Salmonella typhimurium outbreak in Gideon,
Missouri: results from a field investigation.
International Journal of Environmental Health
Research 6:187-193. 1996.

Clark, R.M., J.A. Goodrich, and J.C. Ireland. Cost
and Benefits of Drinking Water Treatment, Journal of
Environmental Systems, Vol. 14(1), pp. 1-30,1984-85.

Corrosion Doctors (CD). Langelier Saturation Index
(LSI) available at their website: http://www.corrosion-
doctors.org. Undated.

      Cowan, C., Mescher, A., Miller, J., Pettway, K. and
      Pink, B. A Framework for Evaluating Water System
      Ownership and Management Alternatives. Group
      Project Report. University of California, Santa
      Barbara, California. April 2005.

      EPA.  Small Drinking Water Systems: State of the
      Industry and Treatment Technologies to Meet the Safe
      Drinking Water Act Requirements. EPA Publication
      Number 600-R-07-110. September 2007a.

      EPA.  Complying with the Ground Water Rule: Small
      Entity Compliance Guide. One of the Simple Tools
      for Effective Performance (STEP) Guide Series. EPA
      Publication Number 815-R-07-018. July 2007b.

      EPA.  Revised Public Notification Handbook - Figure
      1: The Required Elements of a Public Notice. EPA
      Publication Number 816-R-07-003. March 2007c.

      EPA.  Cross-Connection Control: A Best Practices
      Guide. EPA Publication Number 816-F-06-035.
      September 2006a.

      EPA. Distribution Systems: A Best Practices Guide. EPA
      Publication Number 816-F-06-038. September 2006b.

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