EPA816-D-09-001
November 2009
xvEPA
United States
Environmental Protection
Agency
REVIEW DRAFT
CONTROL AND MITIGATION OF DRINKING WATER
LOSSES IN DISTRIBUTION SYSTEMS
-------
Office of Water (OW/OGWDW/DWPD) EPA MC-4606M
EPA816-D-09-001
www. epa. gov/safewater
November 2009
Review ii
-------
Disclaimer
The Drinking Water Protection Division of the EPA Office of Ground Water and Drinking Water has
reviewed and approved this draft guidance manual for publication. Neither the United States
Government nor any of its employees, contractors, or their employees make any warranty, expressed or
implied, or assumes any legal liability or responsibility for any third party's use of or the results of such
use of any information, apparatus, product, or process discussed in this guidance manual, or represents
that its use by such party would not infringe on privately owned rights. Mention of trade names or
commercial products does not constitute endorsement or recommendation for use.
The statutory provisions and EPA regulations described in this document contain legally binding
requirements. While EPA has made every effort to ensure the accuracy of the discussion in this guidance,
the obligations of the regulated community are determined by statutes, regulations, or other legally
binding requirements. In the event of a conflict between the discussion in this document and any statute
or regulation, this document would not be controlling.
Comments regarding this document should be addressed to:
Michael Finn
U.S. EPA Office of Ground Water and Drinking Water
Drinking Water Protection Division
1200 Pennsylvania Avenue, N.W. 4606M
Washington, DC 20460
Finn.Michael@epa.gov
202-564-5261
Review
-------
Table of Contents
Executive Summary viii
1 WATER LOSS CONTROL PROGRAMS FOR PUBLIC WATER SYSTEMS 1-1
1.1 INTRODUCTION 1-1
1.2 GROWING CONCERNS PUBLIC WATER SYSTEMS FACE AND HOW A WATER
LOSS CONTROL PROGRAM CAN HELP 1-2
1.3 WATER LOSS CONTROL PROGRAM COMPONENTS 1-5
2 WATER LOSS TERMS AND CONCEPTS 2-1
2.1 INTRODUCTION 2-1
2.2 THE WATER BALANCE 2-2
2.3 THE WATER AUDIT 2-5
2.4 PERFORMANCE INDICATORS AND BENCHMARKS 2-7
2.5 ECONOMIC CONSIDERATIONS OF REAL LOSSES 2-10
3 METERING 3-1
3.1 INTRODUCTION 3-1
3.2 METER TYPES 3-2
3.3 METERING POINTS 3-5
3.4 METER REGISTERS, METER READING AND AUTOMATIC METER READING 3-6
3.5 METERING PROGRAMS 3-8
4 WATER LOSS PREVENTION PROGRAM ELEMENTS 4-1
4.1 CONDUCTING A WATER AUDIT 4-1
4.1.1 GATHERING SYSTEM INFORMATION 4-1
4.1.1.1 MAPPING - CADD & CIS 4-2
4.1.2 ESTABLISHING PERFORMANCE INDICATORS 4-2
4.1.2.1 ASSESING LOSSES AND DATA GAP ANALYSIS 4-4
4.1.3 COMPARING LOSS CONTROL OPTIONS 4-4
4.2 INTERVENTION 4-4
4.2.1 FURTHER INFORMATION GATHERING 4-4
4.2.2 LEAK DETECTION AND LOCATING 4-4
4.2.2.1 LOCATING LEAKS AND LOSSES THROUGH RECORDS 4-4
4.2.2.2 PHYSICALLY LOCATING LEASKS AND LEAK DETECTION APPROACHES 4-5
4.2.3 FLOW MONITORING 4-6
4.2.4 LEAK DETECTION AIDS 4-8
4.2.4.1 ACOUSTIC DEVICES 4-9
4.2.4.2 THERMAL DETECTION 4-22
4.2.4.3 ELECTROMAGNETIC DETECTION 4-24
4.2.4.4 CHEMICAL DETECTION 4-26
Review iv
-------
4.2.5 LEAK LOCATING SERVICES AND OTHER POTENTTIAL SOURCES FOR EQUIPMENT
AND EXPERTISE 4-29
4.2.6 PREDCITING PIPE FAILURE 4-30
4.2.7 PIPE REPAIR AND REPLACEMENT 4-31
4.2.7.1 PIPE REPAIR TECHNIQUES AND CONSIDERATIONS 4-31
4.2.7.2 PIPE REPAIR/REPLACEMENT PERSONNEL 4-31
4.2.7.3 AVAILABLE EQUIPMENT AND MATERIALS 4-31
4.2.7.4 LEAK REPAIR TECHNIQUES 4-32
4.2.7.5 PIPE REPLACEMENT 4-36
4.2.8 SELECTING REPLACEMENT PIPE 4-38
4.2.9 OPERATION AND MAINTENACE PROGRAM AND PREVENTATIVE MEASURES 4-42
4.2.9.1 EFFECTIVE DESIGN AND CONSTRUCTION 4-42
4.2.9.2 MATERIAL STANDARDS 4-42
4.2.9.3 DESIGN STANDARDS 4-42
4.2.9.4 CONSTRUCTION CONTROL 4-43
4.2.9.5 EFFECTIVE MAINTENANCE 4-43
4.2.9.6 CORROSION CONTROL 4-43
4.2.9.7 VALVE EXERCISING & SYSTEM FLUSHING 4-44
4.2.9.8 EFFECTIVE OPERATIONS AND ACTIVE PRESSURE MANAGEMENT 4-45
4.2.9.9 SYSTEM MODELING 4-45
4.2.9.10 METER ASSESSMENT, TESTING AND REPLACEMENT PROGRAMS 4-45
4.3 EVALUATION 4-45
4.4 SUMMARY-ASSEMBLING A COMPLETE LOSS CONTROL PROGRAM 4-46
4.4.1 PUTTING THE PIECES TOGETHER 4-46
4.4.2 FINDING HELP 4-47
Appendix A - Summary of Selected State Water Loss Policies A-l
Appendix B - Miscellaneous Data B-l
Appendix C - Water Audit Worksheet Examples C-l
Appendix D - Check Up Program for Small Systems (CUPPS) Example D-l
Appendix E - Case Studies of Implemented Water Loss Programs E-l
References R-l
Review
-------
List of Figures
Figure 1-1 Drought Conditions During August 2008
Figure 1-2 Water Loss Control Program Components
Figure 2-1 The AWWA/IWA Water Balance Table
Figure 2-2 Hydrant with Unmetered and Possibly Unauthorized Use
Figure 2-3 Forces Controlling Leakage and Costs
Figure 2-4 Time to Repair a Leak
Figure 2-5 An Example of an ELL Curve
Figure 3-1 Round-Reading Water Meter
Figure 3-2 UFR Valve Flow Profile and Valve Schematic
Figure 4-1 The Benchmarking Process
Figure 4-2 Pipe Rehabilitation Decision Flow Chart
List of Tables
Table 4-1 Data Requirements for a Detailed Management Plan
Table 4-2 Temporary Flow Meter Types
Table 4-3 Listening Rods / Sticks
Table 4-4 Geophone Leak Detection
Table 4-5 Leak Noise Travel for Distances in Distribution Mains and in Service Lines
Table 4-6 Hyrdophone Leak Detection
Table 4-7 Acoustic Fiber Optic Cable
Table 4-8 Electromagnetic Field Detection
Table 4-9 Data Loggers
Table 4-10 Leak Noise Correlators
Table 4-11 Thermal Water Leak Detection
Table 4-12 Ground Penetrating Radar
Table 4-13 Tracer Gas Detectors
Table 4-14 Tracer Liquid Detectors
Table 4-15 Wrapping
Table 4-16 Repair Clamps
Table 4-17 Sliplining
Table 4-18 Replacement (Open Trench)
Table 4-19 Replacement (Trenchless)
Table 4-20 Comparison of Distribution Size Pipe Materials - Material Properties
Table 4-21 Comparison of Distribution Size Pipe Materials - Pipe Properties
Table 4-22 Comparison of Distribution Size Pipe Materials - Operational Considerations
Table A-1 Summary Policy Findings
Table A-2 Selected State Standards for Unaccounted-for Water
Table B-l Estimated per/Capita/Day Water Use by State
Table B-2 Snapshot of high water loss within distribution systems
Review
VI
-------
Acronyms and Abbreviations
AM Asset Management
AMR Automatic Meter Reading
ANSI American National Standards
Institute
ASCE American Society of Civil
Engineers
ASDWA.... Association of State Drinking
Water Administrators
ASTM American Society for Testing
Materials
AWWA American Water Works
Association
AwwaRF .. American Water Works
Association Research Foundation
BABE Breaks and Burst Estimation
CADD Computer-Aided Design and
Drafting
CARL Current Annual Volume of Real
Losses
CUPSS Check-Up Program for Small
Systems
DMA District Metered Area
DWSRF Drinking Water State Revolving
Fund
ELL Economic Level of Leakage
EPA United States Environmental
Protection Agency
FAVAD Fixed and Variable Discharge
Paths
. Gallons Per Minute
. Ground Penetrating Radar
. International Water Association
. Impressed Current Cathodic
Protection
. Infrastructure Leak Index
. International Standards
Organization
MassDEP...Massachusetts Department of
Environmental Protection
NRWA National Rural Water Association
NTNCWS . Non-Transient Non-Community
Water System
GRP
IWA
ICCP
ILL.
ISO.
NSF NSF International (Formerly
National Sanitation Foundation)
O&M Operation and Maintenance
PCCP Prestressed Concrete Cylinder Pipe
PRV Pressure Reducing Valve
PVC Poly vinyl Chloride
PWS Public Water System
SCAD A Supervisory Control and Data
Acquisition
TILDE Tools for Integrated Leak
Detection
WARN Water & Wastewater Agency
Response Network
UARL Unavoidable Annual Real Losses
UFR Unmeasured Flow Reducer
US United States
Review
vn
-------
Executive Summary
Maintaining system infrastructure to deliver clean and safe drinking water to customers is often a
significant challenge for the operators of public water systems (PWSs). Much of the estimated
880,000 miles of drinking water infrastructure in the United States has been in service for
decades and can be a significant source of water loss. In addition to physical loss of water from
the distribution system, water can be "lost" through unauthorized consumption (theft),
administrative errors, data handling errors, and metering inaccuracies or failure. Water is a
commodity that is produced by a PWS; therefore, lost or unaccounted-for water can be equated
to lost or unaccounted-for revenue. A water loss control program can help to locate and reduce
these water losses and thus maintain or increase revenue.
A PWS must balance use of its resources to address the financial and personnel demands of
economic restrictions, water availability, population and climate changes, regulatory
requirements, operational costs, and public and environmental stewardship. A water loss control
program can help identify and reduce actual water losses along with apparent losses resulting
from metering, billing or accounting errors. Water loss control programs can potentially defer,
reduce, or eliminate the need for a facility to expend resources on costly repairs, upgrades, or
expansions. A water loss control program will also protect public health through reduction in
potential entry points of disease-causing pathogens.
A water loss control program is an iterative process that must be flexible and customizable to the
specific needs of a PWS. There are three major components of an effective water loss control
program that must be repeated on a periodic basis to continually evaluate and improve the
performance of a PWS. These three components are the 1) Water Audit, 2) Intervention, and 3)
Evaluation.
Conducting a water audit is a critical first step in developing a water loss control program. A
water audit quantifies the amount of water that is being lost. Most states have regulatory policies
that set acceptable losses from PWS distribution systems at a maximum of between 10 and 15
percent of the water produced by the PWS. This percentage of unaccounted water provides
estimated losses and does not adequately quantify how or why this water is categorized as
"unaccounted-for". Lack of standardized terminology has historically added to difficulties in
comparing water losses from different PWSs. The International Water Association (IWA) and
the American Water Works Association (AWWA) have developed standard methods and
terminology to perform water audits and to assist water utilities in tracking their distribution
system losses. The AWWA/IWA water audit methodology is based on the water balance table,
which specifies different types of water consumption and losses. Through the water audit,
Review viii
-------
options will become apparent regarding how to proceed with further identifying where losses are
occurring or where efforts to control or eliminate the losses should be concentrated.
The Intervention process begins to address the findings of the water audit and can include a
variety of actions such as gathering of further information, implementing metering programs,
adding or changing metering, and detecting and repairing leaks. The selected intervention option
should provide the highest potential benefit value for the resources available that will help to
alleviate a flaw or deficiency in the distribution system.
The evaluation portion of the program consists of assessing the success of the audit and
intervention actions. The evaluation of an intervention action can be as simple as answering a
yes or no question - Was the leak located and repaired? - but more often provides detailed
quantification of the implemented action through the use of performance indicators - The pipe
replacement resulted in areduction ofwater losses of 1,000 gallons per customer per year.
Performance indicators numerically evaluate different aspects of the distribution system and
need to be consistent, repeatable and presented in meaningful standardized units. A performance
indicator (or collection of several) can be used to establish a benchmark. A benchmark allows a
PWS to evaluate its performance over a period of time by repeating the performance indicating
tests and comparing them with previous results. Performance indicators and benchmarks also
allow comparisons between public water providers.
Accurate metering is crucial in a water loss prevention program. Metering establishes
production and customer use volumes as well as provides historic demand and consumption data
that is useful not only for auditing but for planning future needs. There is no single type of meter
that will accurately measure flow for all applications but there are a variety of meters, that have
been developed using different operating principles, designed to perform within required
tolerances under different circumstances. The cost of meters typically ranges from a few
hundred dollars to thousands of dollars per meter depending on size, complexity, and operating
conditions. A PWS must select the meters they use carefully according to intended use, flow
rates, and the environment where it will be installed. How the meters will be read is also a
decision that a PWS has to decide when considering metering programs. Meters can be read
manually but most PWSs are moving toward a variety of different Automatic Meter Reading
(AMR) systems that reduce reading errors and allow labor to be reduced or reallocated.
While it is possible to spot losses through billing data discrepancies or abrupt changes in
amounts ofwater that have been historically used, it is typically necessary to physically pinpoint
the leak in the field. The location of a leak is not always obvious unless it is large. An array of
techniques and equipment are available to assess leakage from distribution lines within a
Review ix
-------
geographic area or pinpoint a leak within a suspected segment of pipe. Flow monitoring of a
District Meter Area (DMA) or step-testing techniques are often used to determine leakage within
an area that can be isolated and may encompass 1,500 to 2,000 service connections. These
techniques monitor flow to specific areas and compare water flowing into the area with known or
estimated night usage to determine losses in the DMA or along a branch water line.
There are several different types of leak detection equipment that use different operating
principles. Acoustic equipment detects a leak through noise made by water as it leaks from the
pipe. Electromagnetic field detection is used on pre-stressed concrete pipe and locates defective
reinforcing steel in the pipe. Thermal detection devices look for the temperature differences in
the surrounding ground caused by saturation due to the leaked water. Chemical detection relies
on locating substances added to the treated water such as chlorine or fluoride that do not occur
naturally. A trace gas may also be introduced into dewatered lines. If there is a leak, a special
instrument can detect it at the surface. The different styles of leak detection equipment require
varying levels of skill and experience to operate with accuracy. Capital costs for typical leak
detection equipment range from less than one hundred to several thousand dollars depending on
its complexity.
Once a leak is located it can be repaired or replaced. Some repair techniques include wrapping,
using repair clamps, or sliplining. Replacement can be done by installing new pipe in an
excavated trench or by use of a trenchless method such as pipe bursting where a new pipe of the
same size or larger is pulled through the existing pipe with special equipment. Micro tunneling
or and hydraulic jacking are other trenchless techniques where pipe is either pushed or pulled
underground without the necessity of large amounts of excavation.
Operations and maintenance (O&M) procedures and standards should also be a part of any water
loss prevention program. Along with ensuring proper design, and installation of new distribution
components, maintenance and operation measures such as system flushing, valve exercising,
meter assessment testing and replacement programs, system modeling, and pressure management
all contribute to improved efficiency, reduction in water losses, and often cost savings.
Developing a complete water loss prevention program requires careful consideration of the water
loss reduction goals a PWS wishes to achieve. The program should be customized for the unique
features of the PWS and be flexible enough to update periodically as the PWS conducts future
audits. Those assembling a water loss prevention program should also remember there is help
available from the EPA, other PWSs, state drinking water primacy agencies, and other drinking
water trade and conservation organizations.
Review
-------
1 WATER LOSS CONTROL PROGRAMS FOR PUBLIC WATER SYSTEMS
1.1 INTRODUCTION
Safe drinking water is a necessity for life. Every day billions of gallons of this precious
commodity are delivered to millions of people across the United States (US). Thousands of
independent water utilities around the nation are dedicated to producing, treating, and delivering
safe water to the public. Significant resources are required to install, operate, and maintain the
infrastructure of a public water system (PWS). PWSs are facing more obstacles and challenges
today than they have in the past with more resource and funding constraints. The infrastructure
of many of the drinking water systems in the US were built decades ago and are currently in need
of attention. PWSs are not only expected to produce safe drinking water at a low cost but must
also address current growing concerns such as limited water availability, increasing water
demands, climate change, increasing regulatory requirements, and limited resources and funding.
The deterioration of the infrastructure of these drinking water systems has become a critical
issue. There are approximately 880,000 miles of drinking water infrastructure in the US. In the
American Society of Civil Engineers' (ASCE) 2005 Report Card for America's Infrastructure it
was estimated that there will be at least an $11-billion annual shortfall over the next 20 years in
funds necessary to replace aging facilities and meet existing and future drinking water
regulations. As the integrity of our aging infrastructure decreases, the loss of finished water in
the distribution system increases. The loss of integrity in the distribution system is evident by
the increasing amounts of reported breaches in distribution systems. The loss of finished water
in the distribution system results in direct loss of revenue for the PWSs. The American Water
Works Association (AWWA) estimated in the Distribution System Inventory, Integrity and
Water Quality publication that there are close to 237,600 breaks per year in the United States
leading to approximately $2.8 billion lost in yearly revenue.
Water loss from a utility's distribution system is a growing management problem that is not only
confined to lost revenue. Water losses in the distribution system require more water to be
treated, which requires additional energy and chemical usage, resulting in wasted resources and
lost revenues. With growing concerns about shrinking budgets, PWSs must look at how they can
optimize their production and revenue. Water lost in the distribution system equals revenue lost.
For these reasons more and more PWSs across the country are implementing water loss control
programs. Not only can a well implemented water loss control program reduce revenue loss but
it can also protect public health by eliminating the threat of sanitary defects that may allow
microbial contamination in finished water.
Review Draft 1-1
-------
This guidance has been prepared for water management administrators, local government
officials, system operators, and others who have an interest in developing programs to reduce
losses from their drinking water distribution systems. The success of a water loss control
program depends on the ability to tailor the program to the individual PWS. This guidance
provides information on flexible tools and techniques that may help the PWS meet their water
loss prevention needs.
1.2 GROWING CONCERNS PUBLIC WATER SYSTEMS FACE AND HOW A
WATER LOSS CONTROL PROGRAM CAN HELP
A public drinking water system must provide enough water to meet demand at a reasonable cost
while maintaining quality standards to protect public health. A PWS and its water management
administrators must balance these goals at the same time they face growing concerns such as:
Water availability
Economic restrictions
Population growth
Climate change and drought
Operational and maintenance costs
Regulatory requirements
Public service responsibility
Social pressures and environmental stewardship
Many of these issues are inter-related. A water loss control program can help to address each of
these issues.
Water Availability
The complexity of PWSs varies with a community's size, composition, and location. All
systems depend on quality and abundant water sources to meet increasing water demands. A
PWS's source may be ground water, surface water, ground water under the influence of surface
water, purchasing finished water from another PWS or a combination of these sources. Each of
these options requires resources and funds to locate, develop, treat, and maintain the source.
When insufficient availability becomes an issue, a PWS has the option to find and develop
another source or buy additional water from another PWS. However, finding a new reliable and
adequate quality source may not always be easy or an option. A third option available to the
PWS is to take a look at their process and operation and determine if there is any way to save
water. This is when developing and implementing a water loss control program at the PWS
becomes essential. Through a water loss control program, water that was previously lost can
now be sold to the consumers, increasing revenue, meeting water demands and reducing the need
Review Draft 1-2
-------
for other sources. Such a program may be able to defer development of new sources and reduce
or eliminate the need to supplement supply from another PWS. The water loss control program
is often the most economical solution.
Economic and Population Growth
Population growth can put an additional strain on a water system. Economic, manufacturing,
and industrial growth in a community can also affect the ability of a water system to provide
sufficient water. Some industries rely heavily on water such as food processing and beverage
companies. These water demand increases must be met either by locating other sources,
increasing the capacity of the existing water treatment facility, or investing in new capital
improvement projects. A water loss control program can help find water that was previously lost
in the system and potentially defer, reduce, or eliminate the need for more expensive alternatives.
Climate Change and Drought
Droughts are naturally occurring phenomena. Periods of drought can contribute to increased
water demand and add strain to the PWSs source water supply. Drought effects can be
especially critical in the more arid Southern and Western regions of the United States.
Governmental agencies track drought data to predict water and resource needs. Drought maps
like the one in Figure 1-1 for August of 2008 can be found at http://drought.unl.edu/dm. A water
loss control program can help lessen the severity of the effects of drought and climate change on
PWSs through retention of more water in their distribution system. This not only has the effect
of retaining more water for the customers, but can lessen the amount withdrawn from the source.
Review 1-3
-------
U.S. Drought Monitor
Augusts, 2008
Valid 8 a.m. EDT
D2A
Intensity:
I _] DO Abnormally Dry
CH D1 Drought - Moderate
d D2 Drought - Severe
H 03 Drought - Extreme
H D4 Drought - Exceptional
Drought impact Types:
r~" Delineates dominant impacts
A = Agricultural (crops, pastures,
grasslands)
H = Hydrological (water)
The Drought Monitor focuses on broad-scale conditions.
Local conditions may vary. See accompanying text summary
for forecast statements.
USDA
http://drought.unl.edu/dm
Released Thursday, August 7, 2008
Author: Brian ritctis. National Drought Mitigation Center
Figure 1-1. Drought Conditions During August 2008.
Source: National Drought Mitigation Center, August 2008
Operational and Maintenance Costs
Water loss control and prevention programs can also benefit the bottom line of a PWS. Reduced
water losses in the distribution system can translate to:
Less electricity required to treat and pump the water,
Potential reduction in the feed rates of treatment chemicals, and
Potential reduction in disinfectant dose.
It can also mean deferred treatment facility upgrades. Savings may also be realized through
reduced equipment maintenance and replacement. Along with fewer breaks and leaks to be
repaired, the service life of distribution piping may be extended through pressure management
and surge suppression schemes. Review of metering accuracy and other metering programs can
recover lost revenues. Metering and pressure management will be discussed further in the
following chapters.
Review Draft
1-4
-------
Regulatory Requirements
Currently, there are no national requirements for auditing and reporting water loss from PWSs,
but some states have taken it upon themselves to begin regulating and assessing water loss from
systems in their jurisdictions. Texas, for example, became a leader in the push to control water
loss with the passing of House Bill 3338, which required all Public Water Utilities to conduct
water audits for 2005 operations and every five years thereafter. The water audit report
addresses four main points of water loss: distribution line loss, meter inaccuracies, accounting
practices, and service theft. Many other states have existing rules regarding losses from PWSs
and are continuing to tighten and enforce these requirements. A water loss control program can
make complying with these existing and future regulations easier.
Public Service Responsibilities
A water loss control program can contribute significantly to a PWSs responsibility to provide its
customers with safe water. Through a water loss control program, potential points of entry for
microbial and other contaminants are reduced, increasing public health protection. Some facets
of the program can reduce main breaks and the collateral damage associated with locating and
repairing these breaks. For example, a water audit may identify sources of water loss in the
distribution system. By addressing water leaks proactively, the PWS can prevent interruptions in
service and reduce the cost of repair. Other potential benefits to the customers include: deferred
rate increases, better distribution system reliability, and improved ability for the distribution
system to meet the higher water pressure and flows required for fire fighting. Combined, these
benefits ultimately increase customer satisfaction and reputation of the PWS.
Social Responsibility and Conservation
In addition to the benefits to the PWS and its customers, a water loss control program can have
further overarching benefits. Increasing social, government and public pressures have changed
the way society conserves water resources to ensure future sustainability. Not only will a water
loss control program help conserve water, but it can directly impact the amount of electricity and
treatment chemicals used. It may lead to conservation of materials and fuels used in
maintenance and repairs. Combined, the reduction in use of these resources can help reduce
greenhouse emissions.
1.3 WATER LOSS CONTROL PROGRAM COMPONENTS
A water loss control program must be flexible and tailored to the specific needs and
characteristics of a PWS. There are three major components to an effective program:
1. The Water Audit
2. Intervention
Review Draft 1-5
-------
3. Evaluation
Each of these major components consists of additional steps and options.
The Water Audit is an assessment of the distribution system and uses accounting principles to
determine how much water is being lost and where. Through the water audit, options will
become apparent as to how to proceed with further identifying where losses are occurring or
where efforts to control or eliminate the losses should be concentrated. These options should be
compared and evaluated not only economically but with consideration of all other issues and
concerns the PWS faces. Typical steps in an audit include:
Gathering information,
Determining flows into and out of the distribution system based on estimates or metering,
Establishing performance indicators (e.g., what parameters will be measured and how),
Assessing where water losses appear to be occurring based on available metering and
estimates,
Analyzing data gaps (e.g., determining if more information is necessary to make
comparisons and an informed decision),
Considering options and making economic and benefit comparisons of potential actions,
and
Selecting the appropriate interventions.
The Intervention process puts the options selected into action. More than one action may be
selected as beneficial to a PWS and the public. For example, the water management
administrator may decide that the PWS has three high priority items including adding additional
metering in one neighborhood, precisely locating and repairing a leak in a specific section of
main, and replacing a one-mile section of pipe. Selecting the order of these actions should be
based on budget constraints, public benefit, and priority of other scheduled capital
improvements. Intervention can include:
Gathering further information, if necessary,
Metering assessment, testing, or a metering replacement program,
Detecting and locating leaks,
Repairing or replacing pipe,
Operation and maintenance programs and changes,
Administrative processes or policy changes, and
Review Draft 1-6
-------
No further action is necessary.
The Evaluation portion of the program consists of assessing the success of the audit and
intervention actions. The evaluation will answer questions such as:
Were the goals of the intervention met? If not, why not?
Where do we need more information?
How often should we repeat the Audit, Intervention and Evaluation process?
Is there another performance indicator we should consider?
How did we compare to the last Audit, Intervention and Evaluation process?
How can we improve performance?
A major portion of evaluation is benchmarking. The audit establishes performance indicators,
which serve as benchmarks. The intervention action should improve performance in some way.
Evaluation is necessary to ensure that whatever the intervention was, it succeeded in its goal. If
the goal of the intervention was not met, the evaluation process seeks to determine why and what
can be done about it.
Figure 1-2. Water Loss Control Program Components.
A water loss control program as a continuous process.
Review 1-7
-------
2 WATER LOSS TERMS AND CONCEPTS
2.1 INTRODUCTION
There is no current comprehensive national regulatory policy that limits the amount of water loss
from a public water supply's distribution system. Most states, however, do have policies and
regulations that address excessive distribution system water losses. The policies vary among
states but most set limits that fall within the range of 10% to 15% as the maximum acceptable
value for the amount of water that is lost or "unaccounted-for."
Neither the term "unaccounted-for-water" nor the use of percentages as measures of water loss is
sufficient to completely describe the nature and extent of distribution system water loss.
Unaccounted-for-water is a term that has been historically used in the United States to quantify
water loss from distribution systems. Unaccounted-for-water, expressed as a percentage, is
calculated as the amount of water produced by the PWS minus the metered customer use divided
by the amount of water produced multiplied by 100, or,
(Water Produced by PWS - Metered Water Used)
Unaccounted-for-Water %= x 100
Water Produced by PWS
Although this percentage provides a rough idea of how much water is unaccounted for, it does
not help answer questions such as is the water really being lost? If so where? Is water that is
used for firefighting or by the city for street cleaning really unaccounted for? What about
inaccurate meters, theft or billing errors? These situations all can contribute to unaccounted
water but do not necessarily mean that there is excessive leakage in the distribution system.
Determining how much water is being lost and where losses are occurring in a distribution
system can be a difficult task. Without consistent and accurate measurement, water losses
cannot be reliably and consistently managed. The confusion over inconsistent terms and
calculations has led to the development of better tools and methods to track water losses from
distribution systems.
The International Water Association (IWA) and the American Water Works Association
(AWWA) began to finalize standard methods to assist water utilities in tracking their distribution
system losses in the last several years. These methods are the foundation of water auditing and
conservation strategies that are now being used successfully worldwide. In order to understand
how to apply the AWWA/IWA methodology, several concepts and terms must be defined and
explained. The AWWA/IWA Water Balance Table (Figure 2-1) is the foundation of the
methodology and defines the terms used in water auditing. The water audit determines the type
and quantity of water loss. Performance indicators can then be calculated to measure the level
and volume of water losses in the PWS. These performance indicators then serve as benchmarks
Review 2-1
-------
to gauge improvement during the next scheduled audit. Performance indicators and benchmarks
are discussed in more detail in Section 2.4.
2.2 THE WATER BALANCE
System
Input
Volume
Authorized
Consumption
Water Losses
Billed
Authorized
Consumption
Unbilled
Authorized
Consumption
Apparent
Losses
(Commercial
Losses)
Real Losses
(Physical
losses)
Billed Metered Consumption
Billed Un-metered Consumption
Unbilled Metered Consumption
Unbilled Un-metered Consumption
Unauthorized Consumption
Customer Meter Inaccuracies and Data Handling
Errors
Leakage in Transmission and Distribution Mains
Storage Leaks and Overflows from Water Storage
Tanks
Service Connections Leaks up to the Meter
Revenue
Water
Non Revenue
Water (NRW)
Figure 2-1. The AWWA/IWA Water Balance Table
Standardized terminology and definitions are crucial to consistent measurement. These
standards are needed to accurately track performance and improvements. In the AWWA/IWA
methodology, all water that enters and leaves the distribution system can be classified as
belonging to one of the categories in the water balance table shown in Figure 2-1; each of these
terms is defined below. The table is balanced because it accounts for all of the water in the
distribution system and the sum of any of the columns should also total the System Input Volume.
System Input Volume is defined as the amount of water that is produced and added to a
distribution system by a PWS. It also includes water that may have been purchased from another
water supplier to supplement the needs of the PWS.
Authorized Consumption is water that is used by known customers of the PWS. Authorized
consumption is the sum of billed authorized consumption and unbilled authorized consumption
and is a known quantity.
Billed Metered Consumption is an authorized consumption that is directly measured. It is the
quantity of water that is metered and generates revenues through the periodic billing of the
consumer.
Billed Un-metered Consumption is an authorized consumption that is based on an estimate or
flat fee. This billing method is used for customers that do not have meters. Estimated use is
Review Draft
2-2
-------
often based on historical or average use data. The fee may vary for different types of customers
such as residential or industrial.
Unbilled Authorized Consumption consists of known uses, condoned by the utility, for which
no revenue is received. Unbilled authorized consumption can be either metered or un-metered.
Unbilled authorized consumption is shown in yellow in Figure 2-1. Some examples might
include filling city street cleaner trucks or a city swimming pool, flushing water lines or sewers,
or water used by the fire department. All are legitimate water uses, with the full cognizance of
the utility.
Unbilled Metered Consumption is that quantity of water that does not generate revenues but
which is accounted and not lost from the system. Water used in the treatment process or water
provided without charges are examples of these quantities.
Revenue Water is water that is consumed and for which the utility receives payment. Revenue
water consumption volume is measured or estimated. Revenue water includes metered and
un-metered billed authorized consumption. Revenue water is shown in green in Figure 2-1.
Non-Revenue Water (NRW) is water that is not billed and no payment is received. It can be
either authorized, unauthorized or result from a water loss. Authorized NRW consists of
unbilled metered consumption and unbilled un-metered consumption.
Unbilled Un-metered Consumption is the quantity of water that is authorized for use by the
PWS but is not directly measured and creates no revenues. Water main flushing and firefighting
are often examples of this category.
Unbilled Metered Consumption is directly measured water use for which there is no charge.
This category can include water use at city government offices, street cleaning or city park
irrigation.
Some PWSs either meter or estimate use by the city or public services such as fire departments
even though no fee is charged. These systems will have an advantage when preparing a water
audit since this information will be required to complete the water balance.
Review 2-3
-------
Figure 2-2. Hydrant With Un-metered and
Possibly Unauthorized Use
Unauthorized Consumption is that quantity of
water which is removed from the system without
authorization and presumably without the PWS's
knowledge. Unauthorized consumption includes
theft by illegal meter by-passes, vandalism or
un-metered hydrant use for construction or
recreation. This water quantity is very difficult to
estimate but must be accounted and is amenable
to reduction through administrative action. Figure
2-2 shows a fire hydrant with a garden hose
attached as an illustrative example of an
un-metered and possibly unauthorized connection.
Unauthorized consumption as in this example can
also be a potential source of contamination because there is no backflow prevention device in
use.
The lower part of the Water Balance Table consists of Water Losses. Water losses are
categorized as either real or apparent. Real Losses, also referred to as physical losses, are actual
losses of water from the system. When performing financial calculations related to real losses,
the water is priced at the cost of production rate since it is not available for a consumer to use
and costs only what it takes to produce. Correcting real losses will result in lower operating cost
through reduced production requirements and reduced water process chemical and electrical use.
Real Losses are the physical leaks shown in grey in Figure 2-1 and consist of leakage from
transmission and distribution mains, leakage and overflows from the utilities storage tanks and
leakage from service connections up to and including the meter. Preventing or repairing real
losses usually requires an investment in PWS infrastructure. Infrastructure investment can
reduce losses such as:
Distribution and transmission main leaks, which represent the quantity of water that is
lost from the system, generates no revenue, can severely damage system reliability if not
corrected and may result in water quality problems.
Storage leaks and overflows from water storage tanks, which consist of the quantity
of water that is lost from the storage facilities within the system. Depending on the
climate and storage configuration, these losses can also be due to surface evaporation.
Service connection leaks, which consist of the quantity of water that is lost from leaks
from the main to the customer's point of use. Even though a leak after a customer's
meter can generate revenues for the PWS and is often the responsibility of the customer,
it is wasteful and can strain customer and PWS relations. Service connection leaks
represent real losses from the system and are frequently easy to detect. In the
AWWA/IWA water audit methodology only service connection leaks up to the meter are
included.
2-4
-------
Apparent losses, also referred to as commercial losses, occur when water that should be
included as revenue generating water appears as a loss due to theft or calculation error. Apparent
losses consist of unauthorized consumption, metering calibration errors and data handling errors.
Apparent losses are shown in orange in Figure 2-1.
Meter calibration error and data error losses can be thought of as accounting losses. This
quantity of water is not lost from the system and generates no revenues but if not included in loss
calculations can produce misleading water loss estimates. These errors arise from service meter
calibration errors, meter reading errors, data handling and billing errors and billing period
variances. These quantities may be reduced through administrative action.
When performing financial calculations related to apparent losses, the water is priced at the retail
rate since it should have been charged at that rate. Recovering apparent losses will not reduce
physical system leakage but it will recover lost revenue. Calibrating or replacing old meters or
enforcing water theft policies can substantially reduce apparent losses.
Water Balance terms help classify and standardize the methods used in the water audit. The
water audit is the starting point for the utility to understand its water loss. The audit is a
methodical approach to account for all water that is placed into the distribution system and
accounts for its ultimate disposition.
2.3 THE WATER AUDIT
The water audit is the critical first step in the establishment of an effective water loss
management program. With the successful completion of a system water audit, the PWS will
have gained a quantified understanding of the integrity of the distribution system and begin to
formulate an economically sound plan to address losses. Water loss in a public water system can
be a major operational issue. Non-revenue generating water can significantly affect the financial
stability of the PWS. Finding and repairing water loss sites can carry its own substantial costs.
The economic trade-offs between value of lost water given it generates no revenue and the
investment to reduce this loss requires careful planning and economic judgment. The PWS
needs to clearly understand the type of loss as well as its magnitude. Water resource, financial
and operational consequences must be weighed when considering whether to fix the source of
the leak. This decision is unique to every system.
There are several published water auditing software systems available for free or at a low cost.
Several can be downloaded from internet Web sites. Care should be taken in selecting and
applying water loss auditing software since many of these tools are based on European models
and use metric units. AWWA provides free audit software that can be downloaded from:
http://www.awwa.org/ResourcesAVaterLossControl.cfm?ItemNumber=48511&navItemNumber
Review 2-5
-------
=48158. A blank water audit worksheet is included in The Texas Water Development Boards'
Water Loss Manual (2005). The manual along with the form can be downloaded from:
http://www.twdb.state.tx.us/assistance/conservation/MunicipalAVater Audit/Leak DetectionAVa
terLossManual 2005 .pdf. The Massachusetts Department of Environmental Protection
(MassDEP) also provides Water Audit Forms and worksheets at its Web site:
http://www.mass.gov/dep/water/approvals/wmgforms.htmtfaudit. Blank Texas Water
Development Board Water Audit Worksheets and Mass DEP forms are included in Appendix C.
A summary of steps to perform an initial water audit is as follows.
1. Determine the amount of water added to the distribution system, adjusted to correct for
metering errors.
2. Determine authorized consumption (billed + unbilled).
3. Calculate water losses (water losses = system input - authorized consumption)
a. Estimate apparent losses (theft + meter error + billing errors and adjustments)
b. Calculate real losses (real losses = water losses - apparent losses).
These steps are an example of a top down audit, which starts at the "top" with existing
information and records. It may also be known as a desktop audit or paper audit since no
additional field work is required. Distribution systems are dynamic. The audit process and
water balance has to be periodically performed to be meaningful to a utility's water loss
management program.
After performing an initial top down audit it may become evident that some of the numbers are
rough estimates and inspire little confidence in their accuracy. The next action in the audit
process is to refine and hone the quantities that may have been initially estimated and begin
reducing non-revenue water losses. A bottom up audit is often implemented after several top
down audits have been completed and can help find the leaks that were not revealed by the top
down audit. A bottom up audit will help with finding real losses and begins by looking at
components or discrete areas in the distribution system. A bottom up audit assesses and verifies
the accuracy of the water loss data associated with individual components of the distribution
system. Bottom up audits are more costly since they are more labor and staff intensive. The top
down audit can help to identify areas where bottom up audit efforts should be concentrated.
Discrete metered areas (DMA) and night flow analysis are two major tools used in bottom up
audits. A DMA is a specific area or section of pipe that can be isolated by closing valves so
inputs and outputs can be monitored. The water flowing into the DMA is metered and compared
with metered customer use. The difference is the water loss for the DMA. DMA analysis is
usually done at night when water use is at a minimum. This night flow analysis minimizes
Review 2-6
-------
errors in the loss calculations by reducing potential customer meter error and by reducing
pressure and use variations.
By standardizing the terminology utility operators can begin to accurately track the performance
of their distribution system and use the water balance and water audits tools to help make sound
financial decisions regarding the operation of their system.
2.4 PERFORMANCE INDICATORS AND BENCHMARKS
Periodically repeating the water audit allows a PWS to monitor its water loss performance over
time or compare itself to other PWSs. This is called benchmarking. Benchmarking uses a
collection of performance indicators to numerically evaluate different aspects of the
distribution system. Performance indicators need to be consistent, repeatable and presented in
meaningful standardized units. Examples of performance indicators include: breaks per mile of
distribution main per year, cubic feet of water lost per service connection, gallons lost per mile of
distribution main, gallons lost per customer, real losses in gallons per year and dollars of
apparent losses per year.
PWSs may use benchmarking to record the values of one or more performance indicators. This
data is then used to compare previously recorded values evaluated with the same units.
Benchmarking can be done at any increment of time: daily, monthly, yearly or every few years.
By benchmarking, a system can:
evaluate its performance;
locate areas where improvement is necessary;
compare itself to other water systems;
evaluate financial options;
gauge itself competitively; and
provide data for reports to the public, regulators and ultimate water users.
Although reductions of water theft and meter validation and replacement programs have their
physical aspects, correction of apparent losses is largely an administrative effort. There is no
physical defect in the distribution system that is allowing water to escape. This is not the case
with real losses.
The AWWA/IWA audit methodology relies heavily on three performance indicators to help
characterize real losses from distribution systems. These performance indicators are the Current
Annual Volume of Real Losses (CARL), the Unavoidable Annual Real Losses (UARL) and the
Infrastructure Leak Index (ILI).
Review 2-7
-------
The Current Annual Volume of Real Losses (CARL) is the volume of water that is lost from
the system due to leaks in the transmission and distribution systems, losses at the utility's storage
tanks and leaks in the service lines from the main to the point of customer usage. The CARL is
given in gallons/day averaged over a one-year period. This total volume is largely
straightforward and easily computed by most utilities. It should be recognized that this volume
contains water losses that can be identified, located and repaired as well as those unavoidable
leaks that every system contains.
CARL (gallons/day) = Transmission Losses + Distribution Losses ( .
+ Storage Losses + Service Line losses ^ ^' '
The Unavoidable Annual Real Losses (UARL) is a subset of a system's CARL leaks that are
unavoidable, which may be too small to be discovered, and may prove to be too expensive or
inaccessible to be repaired. The UARL is also given in gallons/day averaged over a one-year
period. By defining and then calculating the volume of the UARL in the system, an indication of
the Potentially Recoverable Real Losses can be calculated as the difference between the CARL
and the UARL. Unfortunately, UARL are very difficult to estimate. However, AWWA/IWA
research across a large number of systems, together with actual operating data from many
countries has resulted in the development of a relationship between various system parameters
and the UARL with statistically good accuracy. The volume of a system's UARL turns out to be
a function of the length of the distribution system, the number of service connections, the length
of the service lines and the average system operating pressure.
UARL (gallons/day) = (5.41 x Lm + 0.15 x Nc +7.5 Lp) x p (Eq. 2-2)
Where: Lm = Length of transmission and distribution system (miles)
Nc = Number of service connections
Lp = Total length of private pipe (miles)
P = Average pressure in the zone (psi)
Care must be exercised when calculating the UARL for systems where Nc is less than 5,000, P is
less than 35 psi or Nc/Lm is less than 32. Field testing of these systems should be undertaken to
verify and validate the calculated results. The value of Lp in metered systems is the number of
service connections multiplied by the average distance between the curb stop and the customers'
meter. In unmetered situations this is the first point of use within the property. In most US
systems, this pipe is typically not considered to be "private" pipe but rather is the responsibility
of the utility. However, for consistency, the IWA terminology has been used in these definitions.
Review 2-8
-------
The Infrastructure Leak Index (ILI) is an index recommended by the IWA for establishing
utility water loss management targets. The ILI was developed to overcome the shortcomings of
other water loss target systems in use and to generate a verifiable target that could be used for
management of a water loss program readily comparable to industry benchmarking. The ILI is
defined as the ratio between the Current Volume of Real Losses and the volume of Unavoidable
Losses.
CARL
ILI = (Eq. 2-3)
UARL
The ILI is substantially different and more meaningful than the frequently used simple ratio
between unaccounted-for water and total plant production for comparing system efficiencies.
This latter ratio (unaccounted for water divided by plant production) provides only limited
information about the real water loss characteristics of the system. The ratio will not change as
operating conditions are altered. In fact it can even appear to improve when actual water losses
are increasing. For example, a new subdivision goes on line and the total production increases to
meet the additional demand with little if any additional unaccounted for losses. However, the
ratio of unaccounted for water divided by plant production will actually decrease as the plant
production (the denominator of the ratio) increases even though the total quantity of water loss
from the system has not decreased. The system may appear to be more effective than it was the
day before the new portion of the distribution system went on line, but in reality, just as much
product is being lost as before the addition. Such insensitivity makes this old water loss ratio an
ineffective metric for economic or operations planning and is virtually meaningless as a
comparison between systems (benchmarking). The ILI calculation includes pipe length and
other parameters that adjust for changes to the distribution system and make it more useful as a
comparison between different audit periods or even PWSs.
An ILI index of 1.0 indicates that current annual real losses are equal to unavoidable losses and
the PWS is operating efficiently when considering real water loss. Actual ILI values typically
fall in the range of 1.5 to 2.5 for most PWSs. When a PWS uses the ILI as an evaluation
parameter for a water loss reduction project, it must consider the costs it will need to incur and
pass on to its customers to reduce its ILI index. Benchmarking is an indicator of a utility's water
loss situation with respect to previous audits other utilities; it does not define the acceptability or
appropriateness of the loss rate for the particular PWS. Acceptable rates of water loss should be
established by the PWS or may be established by regulatory authorities.
Review 2-9
-------
2.5 ECONOMIC CONSIDERATIONS OF REAL LOSSES
The objective of a water loss control program is to apply all available techniques to recover as
much of the losses as possible. There are limits to what a well-run water loss management
program can achieve. Ideally, no water would be lost, however this not achievable in the field.
There is a point at which it costs more to locate and fix leaks than is economically justifiable. A
balance must be maintained between water loss reduction and costs associated with water loss
reducing measures. A PWS can directly affect real water losses by controlling:
Pressure management;
Speed and quality of repairs;
Active leakage control; and
Pipeline and assets management through selection, installation, maintenance, renewal or
replacement.
Figure 2-3 is a graphical representation of the component parts of lost water and the actions that
an active water loss management program can use to address these losses.
Economic Level of Real Losses
Current Annual
Figure 2-3. Forces Controlling Leakage and Costs
Review Draft 2-10
-------
Source: (Sjevold et al. 2005) IWA/AWWA and European Commission TILDE, D20
Benchmarking Tools.
The cost of a leak projected over a specified period of time can easily surpass the initial cost to
identify and repair or replace the pipe. The magnitude of the water loss from a site is a direct
function of the time it takes to identify, locate and repair the leak. The amount of water lost from
a leak or break is equal to the volume of the leak multiplied by the length of time until the leak is
stopped and repaired. In Figure 2-4 the boxes represent different stages in the life cycle of a
leak. Depending on the size of the leak, time can be the critical factor for each phase. The
individual boxes in the figure represent the volume of water lost for that item. A large leak for
10 days at 1,000 gallons a day represents a loss of 10,000 gallons. A smaller 10 gallon/day leak
for 1,000 days (around 2 years and 9 months) has the same loss.
Awareness
Localization
Repair
Time (days)
Figure 2-4. Time to Repair a Leak
Source: Based on IWA/AWWA diagrams and IWA Leak Location and Repair Guidance Notes, (2007)
Repairing or replacing a leak includes not only the logistics and operations of manually replacing
the pipe but it also involves customer notifications, arrangements for temporary water bypassing
or contracting an outside repair source.
Active leakage control (ACL) is the process of proactively searching for leaks that are not yet
apparent and repairing them. Pipeline and asset management (AM) are discussed throughout this
guidance document.
Review
2-11
-------
Asset management involves documenting and evaluating the components of a water utility to
determine when the optimum time is to replace or repair a component or pipeline. Evaluation of
whether to replace or repair a component not only depends on the economics of replacement or
repair but on impacts to the community served such as potential health effects, inconvenience or
public opinion and perception of the utility.
Pressure management affects water loss rates. Also, the lack of pressure management has been
shown to increase pipe failure rates. These are relatively intuitive ideas since more pressure
means greater flow whether it is through the pipe or through a crack or hole in the side of the
pipe. Higher pressures mean higher stresses on the pipe. Higher pressure also means higher
pressure spikes during pressure surges. These higher values translate into increased failure rates.
The management goal is to meet customer pressure expectations, fire flow requirements and
adequate pressures to operate the system at as low a pressure as is reasonable.
Each of the methods that a PWS has to address real losses also has an associated cost. In Figure
2-1 the CARL sets the existing losses and associated costs and the UARL establishes the loss
reduction a PWS can achieve. The area between is potentially recoverable real losses. The
balance of what makes economic sense for a water loss reduction program for the water system
lies between these two and is called the economic level of leakage (ELL).
The ELL helps compare costs for making decisions whether a leak detection program will pay
for itself or when to repair a pipe versus replacing it. The ELL is the point at which the cost of
reducing leakage is equal to the benefit gained from leakage reductions. This can become a very
involved process and requires comparing different scenarios. Figure 2-5 illustrates the general
approach. The real cost of the volume of water that is lost is proportional to the time that the
leak starts until it is repaired. If the leak management program allows for minimal field
inspections, the probability of a leak going undetected for an extended amount of time increases.
A program with frequent field visits minimizes the time to detect leaks and hence reduces lost
revenue and volume of finished water.
The cost to detect and find the leak should also be accounted for in the final estimate. A program
with infrequent leak detections will have a very low detection cost per year. Conversely, a
program with a frequent detection cycle will experience high annual costs. It is important to
point out that this cost does not include the cost of repair since these costs would be very similar
regardless of the time it took to detect the leak. The cost per year to conduct a field investigation
diminishes exponentially as the number of detection cycles decreases. A parabolic cost curve is
formed, rapidly falling from many cycles per year to achieve very low water loss to relatively
low total cost per year for programs that are willing to have greater leak loss but only detect
infrequently. However, even though a utility may elect to have a frequent detection cycle, there
will be a minimum at which no amount of detection effort will find the leaks. At this point, the
Review 2-12
-------
cost of detection line (green in Figure 2-5) becomes asymptotic to the "background' leakage
levels.
The total cost of leak detection is therefore the sum of these two opposing cost curves. The
resultant saddle-curve provides a minimum program range at which the detection frequency is
balanced with the amount of water loss from the system. This is known as the ELL range.
-^
c
o
-------
3 METERING
3.1 INTRODUCTION
Meters are very important for all aspects of the water audit process. They make it possible to
charge customers for the water they use. They record usage and therefore make billing fair for
all customers. They can encourage conservation by making customers aware of their usage.
They help detect leaks and establish accountability. Meters allow a PWS to monitor treated
water output and demand. Meter records provide historic demand and customer use data that is
used for planning purposes to determine future needs. In short, metering data makes accurate
water auditing possible.
Selection of a meter for a given application depends on many factors including:
Meter operating principles
Required accuracy
Convenience and ease of use
Volume of flow and flow rate
Types of flow (laminar vs. turbulent)
Range of flow
Installation location and orientation
Required power
Data logging requirements
Durability
Debris and particle tolerance
Temporary vs. permanent installation
Calibration and required maintenance
Size of pipe
Type of pipe
Pressure drop
Meter orientation
Flow obstruction tolerance
Meter reading methods
Temperature and environment
There is no single type of meter that will accurately measure flow for all applications. A meter
has to be selected to meet the location requirements and the conditions where it will be installed.
Several types of meters have been developed to meet different requirements. Each of these
meter types have advantages and disadvantages. Proper meter selection can be complicated and
there are several references that can provide in-depth direction for metering choices and selection
including: AWW As M6 manual Water Meters-Selection, Installation, Testing and Maintenance
and the Bureau of Reclamations' Water Measurement Manual available at
http://www.usbr.gov/pmts/hydraulics lab/pubs/wmm/index.htm.
Metering is important to all aspects of a water loss control program. Meters provide the data to
audit a PWS for water loss, determine where leaks are occurring and determine if intervention is
necessary, and establish performance indicators to evaluate the status of water loss within a
PWS.
Review Draft
5-1
-------
3.2 METER TYPES
There are several ways water meters can be classified but meters encountered in water
distribution systems either operate based on principles of positive displacement or the velocity of
flowing water. These operating principles as well as some examples of these types of meters are
briefly described below. Meters used in water treatment and distribution systems can be further
classified in one of five major categories based on the operating principle or use: The five major
categories of meters are as follows:
1) Velocity Meters operate based on measuring the velocity of flowing water through a known
cross-sectional area to obtain a flow rate. The volume of water passing through the meter
can then be calculated by multiplying the flow rate by the period of time being considered.
There are several sub-categories of velocity meters that measure the flow by different
methods. They include the following:
Propeller, turbine, paddlewheel and multijet meters measure the velocity of water
by placing an impeller in the water flow. The force of the water on the impeller
causes it to rotate at a speed proportional to the velocity of the water. The impeller is
connected to gears or an electronic device that computes the flow based on the
velocity of the water and the area of the pipe. The method of operation for these
meters is mechanical in nature so their accuracy can be subject to wear, interference
from debris in the water and mineral or scale buildup on the operating mechanisms.
These types of meters require insertion into the pipe, which also requires a pipe tap.
They operate more accurately at higher steady flow rates because there can be a slight
lag in impeller rotation when starting and stopping, which can reduce accuracy.
These meters are best suited for use in larger water mains where flow rates do not
change quickly. Some models are smaller and can be used as insertion meters to
temporarily monitor flow. Propeller, turbine, and paddlewheel meters are sensitive to
turbulence in the pipe (especially smaller meters) and require a straight length of pipe
before and after the meter so that the flow becomes steady and non-turbulent. The
distance measured before and after the meter is often specified as some number
multiplied by the diameter of the pipe so that the specified distances are dependent
only on the pipe diameter that is being metered. The length of pipe before and after
the meter can range from 10 to 30 pipe diameters.
Ultrasonic meters, also called acoustic meters, transmit an ultrasonic signal into a
pipe at a diagonal angle. The signal frequency that returns to the meter's receiver is
altered by the flowing fluid or particles in it. The frequency shift is proportional to
the velocity of the water. The flow can then be calculated based on the measured
velocity and the cross-sectional area of the pipe. Ultrasonic simply means that the
acoustic signal is above audible human detection. There are basically two types of
ultrasonic meters, Doppler effect ultrasonic flow meters and time-of-transit ultrasonic
flow meters. Doppler effect flow meters have one probe that contains both a
Review 3-2
-------
transmitter and receiver. Doppler meters rely on suspended particles or air bubbles in
the water to reflect the signal. Treated drinking water does not typically contain
enough suspended particles for Doppler meters to operate properly and they are not
often used for clean water applications. Transit-time flow meters transmit an
acoustic signal from an upstream transmitter/receiver diagonally through the pipe to a
downstream transmitter/receiver. The downstream transmitter/receiver also transmits
a signal along the same path to the upstream transmitter/receiver. The difference in
the travel times in the signals transmitted from the upstream versus the downstream
time is related to the velocity of the water in the pipe. The velocity and pipe size are
then used to calculate flow rate. This type of meter may also be referred to as time of
flight, time of flow, or time of transit meters. Advantages of this type of meter are:
there is no obstruction to flow, they are portable and can be clamped on, there are no
moving parts to wear out, they can be used with different pipe sizes and they can
measure flow in either direction. Disadvantages include their sensitivity to bubbles
and turbulence in the flow and the precise alignment and set up requirements. The
pipe material itself, along with the internal and external surface conditions, can affect
the signal and therefore accuracy of transit flow meters. These meters work best on
cast and ductile iron pipe. Most transit flow meters require an external power source
of 90 to 250 volts AC. There are some models that operate on lower DC voltages that
can be powered by step down transformer or rechargeable batteries.
Electromagnetic flow meters, often called magmeters, operate based on the
principle that water flowing through a magnetic field will produce a voltage which is
proportional to the velocity of the water. The measured voltage is then converted into
a flow rate. There are two general types of these meters: in-line magmeters and
insertion magmeters. In-line magmeters are constructed so that the magnetic field is
created around the diameter of the pipe. The coils that create the magnetic field and
sensing probe are arranged so there is no change in diameter in the pipe and no
obstruction to the flow. This type of meter is installed in the pipeline as a permanent
short length of pipe. Insertion magmeters are inserted into the flow and require a
pipe tap. Insertion magmeters form the magnetic field around the probe inside of the
pipe. Insertion meters are often used for temporary metering. They have the
advantage of being sealed and have no moving parts to foul or wear. In-line
magmeters typically require a line voltage power source of 90 to 250 volts AC while
the insertion meters can operate on DC currents that range from a few volts to 30
volts.
Differential pressure gauges use a pressure drop that occurs when the water flows
through a restriction or around an obstruction in the pipe. The pressure drop is related
to the water velocity and from this relationship the flow rates and volumes can be
determined. There are several types of meters that operate on this principal, they
include: pitot rods, flow tubes, venture tubes and orifice plates. Pitot rods are
relatively inexpensive insertion meters that are often used for temporary flow
measurements. The pitot rod itself forms the obstruction that creates the pressure
differential which is used to measure the flow rate. Although pitot rods are often used
as temporary meters, they do require a pipe tap for installation. Flow tubes consist of
Review 3-3
-------
a funnel shaped obstruction placed in the pipe that creates a pressure differential
between the large and small opening of the funnel shape. The funnel forms the
restriction that creates the pressure differential used to measure the flow rate. The
pressure differential in venture tubes is created by a gradual narrowing of the pipe
diameter followed by a short section of a smaller diameter pipe. The pipe then
increases gradually to the original diameter. The pressure differential used to
measure the flow rate is measured at the original pipe diameter and the reduced
diameter section. Orifice plates are round plates with a hole of a specific size bored
in them. The plate is placed in the pipe such that the flow has to pass through the
restricting hole. Pressures upstream and downstream of the plate are compared to
determine the flow rate. By nature of their measurement method, differential pressure
gauges restrict the flow in some way and require pipe taps to measure the pressure
differential, but they are simple devices with no moving parts and can maintain
accuracy over long periods of time.
2) Positive Displacement Meters separate the flow into known volumes and keeps a running
count of these volumes to measure the accumulated flow. The meters use some form of
vane, gear, piston, diaphragm or disk to separate the measured volumes. These meters are
sensitive to low flow rates and accurate over a fairly wide range of flows. There are typically
two types of positive displacement meters used in the drinking water industry, nutating disk
and piston meters. These types of meters are used in homes, small businesses, hotels and
apartment complexes. They are available for pipe sizes from 5/8 inch to 2 inches. Nutating
disk meters have a round disk that wobbles or "nutates" around a spindle in a cylindrical
chamber. The wobble of the disk in the chamber is caused by the flow of the water. Each
rotation represents a specific volume that is registered. Piston meters, also known as
rotating piston or oscillating piston meters, have a piston that oscillates back and forth as it
rotates. The piston is forced to rotate as water flows through the meter. Each rotation
represents a specific volume that is registered. Other types of positive displacement meters
include reciprocating piston, rotary vane or sliding vane, rotary gear, rotary oval or rotary
lobe but these are not common in drinking water distribution systems.
3) Compound Meters measure over a wide range of flows. The meter contains a velocity
meter and a positive displacement meter. The positive displacement meter measures the
lower flows and the velocity meter (usually a turbine meter) measures the high flows. A
valve regulates which meter is measuring the quantity of water used based on the rate of flow
required. These meters can be used in factory settings where demand during production
hours is much higher than off hours.
4) Proportional Meters measure a small portion of the flow in a pipe. Differential pressure
techniques are used to divert a small portion of the flow from the main pipe through a meter.
After passing through the meter the flow is returned to the main pipe. The flow through the
meter is multiplied by a factor based on the pipe size to determine the flow through the pipe.
These meters may also be known as fire-line meters, bypass meter, or shunt meters and are
most often used in larger diameter pipes. The advantage of this metering method is high
flow rates can be achieved with little obstruction or pressure loss due to a meter.
Review 3.4
-------
5) Open-Channel Meters as their name implies measure flow in open channels. There are two
major types of open channel meters: weirs and flumes. There are different styles of weirs
and flumes but each uses the same principal for measurement. Weirs measure the depth of
water flowing over a rectangular or notched wall of a known size. The depth of water is
related to the flow rate. Flumes are a specially designed section of channel. All of the water
flow in the channel is directed through it. The depth of flow in the flume is related to the
flow rate. Flumes and weirs are designed to be used for open channel flow and are not
typically used in distribution systems.
3.3 METERING POINTS
Meters can also be classified by their placement and usage. Meter placement is critical for water
audits and leak detection. Six types of meter usage based on placement in the distribution
system are described below: master meters, submeters, district meters, component meters,
service meters and temporary meters.
Master Meters or Production Meters record the output of finished water flowing into the
distribution system. A master meter can also be used to measure water being sold from
the plant or a take-off point in the distribution system to another system.
Submeters are typically installed by a company or private entity other than the PWS to
track or bill water use by an individual process or housing unit. Submeters are installed
after the utility owned service meter. A landlord, property management firm,
condominium association, homeowners association, or other multi-tenant property might
use submeters to bill tenants for individual measured water usage. A PWS does not
typically submeter but might encourage submetering programs to promote water
conservation. A PWS may also be interested in submetering if a municipality bills for
both water and wastewater treatment based on the volume of water that is supplied to the
customer. In this billing system, the wastewater is billed on the metered volume
delivered based on the assumption that a sizeable percent of the water being metered into
the premise is going to be returned as wastewater to be treated. For a user with a large
percentage of the delivered water not returned as wastewater, the assessed fee may be
reduced based on a submeter reading. The submeter determines the amount of water that
is not returned to the system and will not have to be treated as wastewater. A soda
beverage bottling plant is one example, since a large portion of the water is bottled and
shipped off site.
District Meters or Zone Meters measure the water used by a large group of users within a
defined area such as a residential or business district. District meters are used to
determine if leaks or losses are occurring within the metered area.
Process Meters or Component Meters are frequently used to carefully measure
chemicals or water used in a process or through specific piece of equipment. Meters at a
pumping station could also be considered to fit in this category.
Review 3-5
-------
Service Meters or End User Meters measure the consumption by water users in the
system at the service line (where the line goes from the distribution line to the
household). Typically one service meter is positioned on the service line just past its
connection with the distribution main.
Temporary Meters or Portable Meters can be used wherever it is necessary to determine
a flow, confirm meter accuracy, help locate losses, perform field testing or determine a
user's consumption profile. These are typically some form of an insertion meter.
3.4 METER REGISTERS, METER READING AND AUTOMATIC METER
READING
Meter Registers. The register is the part of the meter that records the volume of water that has
flowed through the meter. The register is either mechanically or magnetically linked to the
metering mechanism. Most registers display an accumulated total of all water that has passed
through the meter after its installation. Many meter manufacturers provide different registers to
meet the requirements of their customers. Different registers can record the water volume in
units of cubic feet, cubic meters, US gallons, Imperial gallons or liters. In the United States, US
gallons or cubic feet are the most common. Registers can also be arranged to record detailed
information over a period of time using a device called a data logger. The register can also send
the data to a remote data reading device for billing purposes.
Meter Reading. Residential and service meters have a mechanical or digital display for
monitoring and recording the volume. Direct read or straight reading meters are the most
common meters and have a numerical display similar to the odometer on an automobile and the
volume can be read directly. Many of these will also have a hand that sweeps around the dial
showing the instantaneous water flow. They often will have a small triangle or star shaped
indicator that rotates even at extremely low flows.
This indicator is used to determine if there is a leak
occurring downstream from the meter. If all of the
water in a metered facility has been turned off and
the triangle is still spinning, then there is likely a
leak. Some meter models, especially older ones,
might have an arrangement of six or seven circular
dials on the meter face. These are round-reading
meters. Each of the smaller dials represents a
multiplier for the number shown on the individual
smaller dial face. The multipliers are 100,000,
10,000, 1,000, 100, 10 and 1. Some models may _ ^ _ . , ,.
Figure 3-1. This Round-Reading
have a large sweep indicator that represents a 0.1 Meter Registers 806323 Cubic Feet
Review
-------
multiplier. The indicators show the number to multiply by. If the arrow is between numbers, use
the smaller of the two. The flow through the meter is simply the sum of all of the individual
smaller dials. When reading these types of meters, you must pay attention to the direction of the
scale numbers on the individual dials. Some of the scales increase in a clockwise direction and
some of them decrease in a clockwise direction. See Figure 3-1.
Meter reading occurs on a set schedule based on the billing cycle. Meters are either read
manually by a utility worker or read automatically by an Automatic Meter Reading (AMR)
system.
Manually Meter Reading require the reader to correctly read and record the metered value.
The raw recorded values are then entered into a billing system. Manual read systems are more
labor intensive and have higher potential for human error. Errors in manually read meters can
allow data errors to affect billing and water audit accuracy. Because manual meter reading is
labor intensive, it works best for smaller water systems. Advantages of manual meter reading
can include lower initial meter costs and billing system simplicity. Another advantage of manual
meter reading includes the fact that the utility's meter reader may spot potential problems before
they become serious or locate unauthorized use since they have to visit each meter.
Automatic Meter Reading systems can provide many advantages over manually read meters.
AMR is a technology that automatically collects data from the meter and transfers it to a central
database for analyzing and billing. Depending on the AMR system used, fewer employees might
be necessary for meter reading, less gasoline might be used for the meter reading route and the
data can be processed quicker. Some systems can even provide real time trend analysis. Some
of the more popular AMR technologies include:
Handheld data collection where the reader has a data logger that needs to be brought into
the proximity of the meter. The meter is touched or "swiped" to download the
information to the portable unit that collects the data from the route and is then later
downloaded to the utility billing software. This type of system still requires a meter
reader to access each meter but reduces recording errors and increases efficiency.
Mobile data collection is similar to the handheld version but requires the reader to only
drive by the general location of the meter that automatically uploads its stored
information to the mobile unit. A data logger in the vehicle collects the information via a
short-range radio signal.
Other systems use network technologies based on telephony platforms (wired and
wireless) or radio frequency (RF) including WiFi, (a computer protocol), to transmit the
data to the central data collection location.
Review 3.7
-------
3.5 METERING PROGRAMS
Metering programs involve several aspects of the revenue stream for a PWS. Metering
establishes billing procedures and income. Metering and accounting systems can also help detect
leaks and other losses. Metering also has aspects that require expenditure including installation,
maintenance, calibration, testing and replacement.
The Meter - Billing Relationship. Meters and metering programs are an integral part of billing
systems. Many small utilities charge a flat monthly rate for water and might meter only for some
large-use customers if at all. Flat rates may be based on type of use such as residential,
commercial, industrial or agricultural, or they might be based on occupancy. Systems that use
flat rates alone with no metering are usually smaller and might not have the resources to maintain
equipment and accounting systems that are necessary for metered billing. A decision by a small
PWS to add metering will also involve extra effort to maintain the meters and billing systems.
Larger systems usually have some form of metered billing system. Water rates can be based on
customer type or quantity of water used. Rates may increase as proportionally more water is
used or actually decrease with increased use. Metering is also used to determine performance
and system efficiencies by monitoring specific equipment or areas. Accurate metering is crucial
to performing a meaningful water audit.
Establishing a metering program is a good step if you are a small or medium water system and
do not have a metering program. While individual customer metering may be out of the
financial reach for your system, zone metering may be a way to achieve more accurate billing
and gain system operating information at a reduced cost. A PWS must consider available funds
for a program and answer questions such as:
Where do we want metering?
How many meters will we need?
What type of meter is appropriate?
What method of meter reading will we use?
How do we integrate the new meters into our billing system?
Is a new billing system required?
Are the meters upgradeable?
Does our PWS staff install them or should we have them installed by a contractor?
Who will test, calibrate, maintain and replace them?
How do we pay for the program?
Review 3-ฃ
-------
Initial capital costs required to purchase and install the meters may come from the operating
budget of the PWS, a grant, a tax levy, a water rate increase, or municipal bond. Low interest
loans may also be available from a state's drinking water revolving fund. More information
about the Drinking Water State Revolving Fund (DWSRF) can be found at the DWSRF web site
http://www.epa.gov/safewater/dwsrf/index.html. Ideally, the newly installed meters will at least
partially pay for themselves in new and recovered revenue.
Installation. Following the manufacturer's installation instructions for a meter is also crucial to
proper operation. A properly calibrated meter can register incorrectly if installed improperly.
Meter sizing is very important since the accuracy of the meter is dependent on its design type
and design flow. Some meter locations require compound meters with dual registers to properly
record widely varying flow rates. In some cases, an authorized meter bypass is necessary
because the meter restricts flow at higher rates. A bypass might be necessary in emergency
situations at industrial, commercial or multi-residential facilities to allow unrestricted flow
around the meter for fire control systems.
Calibration and Testing. Over time, most water meters fail to register an increasing proportion
of the water flow through them. Under-regi strati on results in lower billing and loss of potential
revenue while at the same time erroneously indicating an increased level of water lost from the
system. Just as with any mechanical or electrical system, meters are subject to inaccuracy or
failure if not installed or maintained properly. Some of the common problems that necessitate
calibration and testing of meters include:
Incorrect installation or sizing,
Higher or lower flows than designed for,
Debris in the water,
Scale build up due to minerals in the water,
Tampering,
Environmental extremes including high or low temperature or vibration, and
Wear.
Meters should be calibrated according to manufacturers' instructions. A PWS should
concentrate on testing accuracy of customers who consume more and have larger meters since
errors in the larger meters will result in higher revenue losses. Depending on installation
methods, residential meters can be tested in place or might have to be removed. Meter testing
can be done with portable testing and calibrating equipment or the meters can be sent to a
company that tests, calibrates and refurbishes them. Many water systems test only a
Review 3.9
-------
representative sample of residential meters and base their decisions to replace or repair meters in
a selected area on the results of the tested sample. In their M-36, Water Audits and Leak
Detection manual, the AWWA suggests 50 to 100 meters is a good number to test. The number
of meters tested may need to be larger and depends on the number of meters in the PWS and the
statistical confidence levels with which the PWS is comfortable. The more meters that are
tested, the more accurate the results will be. State public service commissions often require
periodic testing of water meters. For residential meters (5/8 inch) the required testing period can
range from 5 to 20 years depending on the state. Larger meters may require more frequent
testing.
Replacing. If the PWS has older meters in its distribution system, it might be a good idea to test
or replace them. Determining when the optimum time to replace meters and setting up a
replacement program can require a complex analysis. An analysis similar to the ELL (see
section 2.5) can be undertaken to find the point where a meter replacement program provides the
most economic benefit. The optimum point is based on the cost of installation verses the value
of recoverable losses. In the past it was recommend that residential water service meters be
replaced on a rotating schedule of anywhere from 10 to 20 years but current strategies are more
complicated. These strategies are based on: the number of meters in the system, results of meter
testing, types and sizes of meters, period of service, water quality, available staff to perform the
work, and cumulative volume that has passed through the meter.
Unmeasured Flow Reducers as an Addition to Meters. Another recent development to
consider is an unmeasured flow reducer (UFR). Very low flows in some meters may not
register, therefore revenue is lost and water audit accuracy is skewed. A UFR is a component
that is put in line with the water meter. At very low flows, the UFR changes the flow profile
from a continuous flow that does not register on a meter to a pulsed flow that periodically
activates the meter. At higher flows the device remains open. Figure 3-2 shows the flow
profiles and the UFR valve in the closed and open positions.
Review 3-10
-------
Without UFR
With UFR
Water Meter Threshold
13
1
Time
Time
-
UFR closed; downstream pressure
decreases because leakage
UFR opens; downstream pressure
equals that of upstream
Figure 3-2. UFR Valve Flow Profile and Valve Schematic.
Source: Courtesy of ARI Flow Control Accessories Ltd.
Review Draft
3-11
-------
4 WATER LOSS PREVENTION PROGRAM ELEMENTS
4.1 CONDUCTING A WATER AUDIT
Regardless of whether you are in the initial stages of developing a water loss prevention program
or already have a well established program, collecting and maintaining information on the
elements and condition of components in your distribution system will lead to more accurate
water audits. Information collected for a water audit is only the first step and only a portion of
the data necessary for a complete water loss prevention program. The knowledge base of
potential weaknesses of your distribution system and locations where the most benefit per dollar
invested can be achieved will increase as more water audits are performed. When audit results
are combined with benchmarks and detailed distribution system data, the PWS management can
become more proactive in its operations planning. Chapter 2 provided the definitions and basics
to understand a water audit program and conduct an initial water audit. This chapter is intended
to help a PWS add accuracy to their water audits. It should also be helpful to provide for a more
robust and extensive water loss prevention program beyond the basic requirements.
4.1.1 GATHERING SYSTEM INFORMATION
The effectiveness of your water loss program increases as you expand the type and amount of
information that is collected. Table 4-1 shows some of the distribution system details that should
be collected and maintained. In addition to piping information, data should be maintained for
other components within the water system including: meters, valves, storage tanks, fire hydrants,
pumping and pressure boosting stations, and distribution system controls and monitoring
equipment. While all of the data maintained for a distribution system can provide valuable
information, maps showing the locations of the assets are critical.
Asset management, data storage, and organization can be as simple as a log book or spreadsheet.
EPA has developed the Check-Up Program for Small Systems (CUPSS) to assist with asset
inventory and management activities. CUPSS is a free, easy-to-use, asset management tool for
small drinking water and wastewater utilities. CUPSS provides a simple, comprehensive
approach based on EPA's highly successful Simple Tools for Effective Performance (STEP)
Guide series. Use CUPSS to help you develop:
A record of your assets,
A schedule of required tasks,
An understanding of your financial situation,
A tailored asset management plan.
Review 4-1
-------
More information on CUPSS can be found at http://www.epa.gov/cupss/. A brief description of
the CUPSS software and some screen captures from the program can be found in Appendix D.
Table 4-1 Data Requirements for a Detailed Management Plan
Physical
Year of Installation
Diameter
Material
Length
Location
Interior Lining
Exterior Protection
Joint
Wall Thickness
Soil conditions
Internal Condition
External Condition
Exist
Y
Y
Y
Y
Y
A
A
A
A
A
A
A
New
Y
Y
Y
Y
Y
Y
Y
Y
Y
A
Performance
Complaint Frequency
Type of Complaint
Break Frequency
Type of Break
Reason for Break
Service (hydraulic)
Adequacy
Fire Flow Adequacy
Exist
A
A
A
A
A
Y
Y
New
Y
Y
Y
Y
Y
Y
Y
Commercial/Service
Critical Customer
Affect on Community
No. of People Served
Length of Shutdown
Coordination w/Others
Exist
Y
Y
A
A
A
New
Y
Y
A
A
A
Y = yes, in all cases A = as needed, or as available
Source: Based on (USEPA, 2002) Deteriorating Buried Infrastructure Management Challenges and Strategies
4.1.1.1 Mapping - CADD & CIS
Determining size and location of a water system's piping and other assets is the first step in data
gathering. Almost all systems will have an existing map of their water lines and assets. Some
systems use hardcopy maps while others use their own Computer Aided Drafting and Design
(CADD) system or Geographic Information System (GIS) packages to update the distribution
system inventory. Mapping software packages range in price from a few hundred dollars to
several thousand dollars. CADD and GIS software can help keep necessary information current
and easily accessible. The ideal tracking tool will depend on the complexity of the distribution
system and the sophistication of the tracking that a PWS needs. There are some lower cost and
free CADD and GIS software packages available for water system managers who want to begin
electronic mapping with minimal expense.
4.1.2 ESTABLISHING PERFORMANCE INDICATORS
A proactive water loss control program requires that a water audit is completed and performance
indicators and benchmarks are established. This guidance document concentrates on
performance indicators related to control and mitigation of water loss in the drinking water
distribution system but when establishing performance indicators and benchmarks, the PWS
administrators should consider other potential benchmark categories.
Review Draft
4-2
-------
Section 2.4 of this guidance
document defined performance
indicators and benchmarking
and discussed the CARL,
UARL, and ILI as indicators of
the status of the distribution
system. The CARL, UARL
and ILI are operational
performance based indicators
and would be recorded as
performance indicators in the
water system performance
benchmark category. Other
examples of benchmark
categories a PWS administrator
should consider include:
financial performance,
customer satisfaction,
employee safety, and employee
training.
Each PWS is unique so
establishing performance
indicators and benchmarks will
be dependent on the priorities
and goals set by the water
system administrators;
however the general steps are
shown in Figure 4-1. There are many free or low cost performance indicator and benchmarking
software programs from drinking water agencies around the world that are available on the
internet to simplify instituting a benchmarking program. For more information on benchmarking
and discussion of some of the available benchmarking software programs, see the publication
D20 Benchmarking Tools, from the European Commission's Tools for Integrated Leak Detection
(TILDE) program (EC Contract No. IPS-2001-42077 December 2005). It is available at:
http://www.waterportal.com/comunication/document/D20Benchmarkingtools.pdf.
C Start ^
Plan
1) Determine the priorities of your water system.
2) Select performance indicators and benchmarking
parameters to track.
3) Develop your process and document it to ensure it is
repeatable.
Implement
1) Implement your plan.
2) Observe and analyze performance indicators and
record benchmarks.
Evaluate, Adjust & Correct
1) Periodically evaluate the performance of all
benchmark parameters. (Is there improvement?)
2) From analysis and evaluation make adjustments and
corrections to increase system performance and
efficiency.
3) Consider whether priorities have changed or if new
parameters should be measured.
C Repeat J
Figure 4-1. The Benchmarking Process.
Review Oral!
4-3
-------
4.1.2.1 Assessing Losses and Data Gap Analysis
Once baselines have been established, undertake an analysis to determine where water loss
prevention improvements can and should be made. Start with the obvious problems that can be
remedied within budget then examine larger issues that may involve further analysis or a large
financial investment. Review and compare your options through economic level of water loss
and other financial analyses then prioritize needs. Once a course of action has been selected, the
PWS should arrange financing and set schedules to complete the task.
4.1.3 COMPARING LOSS CONTROL OPTIONS
In addition to the economic level of water loss as a tool to assist in assessing losses, cost/benefit
analysis between options is extremely useful. Cost/benefit analysis allows for direct comparison
by converting all aspects of competing options to present dollar values so they can be compared
on an equivalent dollar for dollar basis. An option that should be included in nearly all
cost/benefit analysis comparisons is the option of "taking no action." When discussing a leak
prevention program, the "take no action" option compares the cost of a leak over a period of time
to other optional interventions and loss control options.
4.2 INTERVENTION
4.2.1 FURTHER INFORMATION GATHERING
Both water audits and performance indicators will identify operational areas where more data
should be collected. Periodic water audits and performance indicator reviews will help to isolate
where losses are occurring and how much is being lost. In many cases it may be necessary to
install additional meters, establish DMAs or review records in greater detail to further narrow the
physical search effort for losses.
4.2.2 LEAK DETECTION AND LOCATING
4.2.2.1 Locating Leaks and Losses Through Records
It is possible to spot losses through billing data discrepancies or abrupt changes in amounts of
water that have been historically used. Some existing billing software packages have built in
functionality to flag historical water use changes. Desktop spreadsheet software can also be
programmed to flag water use changes with a little effort. AMR systems that can track and show
usage profiles at more than monthly or quarterly billing intervals may also be instrumental in
finding either real or apparent losses. Sudden increases in meter readings may be a sign of
leakage, theft or an open valve that should be closed.
Review 4.4
-------
Accounts that have been estimated but not read for several billing periods should also be
reviewed since the estimated usage may be quite different from the actual usage. It is prudent to
re-calculate assumed estimates periodically to ensure that water usage patterns in the area have
not changed when meters are not available to correlate the data.
4.2.2.2 Physically Locating Leaks and Leak Detection Approaches
Identifying system leaks can pose a challenge. While operating personnel might identify some
leaks in the distribution system during routine field inspections, not all leaks are visible. Planned
maintenance will help identify leak occurrences. To better understand how water leaks are
detected, water managers should look at three major water loss leak detection categories: (1) leak
detection through appearance, (2) leak detection through flow monitoring and, (3) leak detection
aids (acoustic, thermal, electromagnetic, tracer, etc.).
Leak Appearance
AWWA estimates that the average lifetime of a slowly developing leak, from its inception until
its repair averages two years (AWWA M36, 1999). Development of a leak depends on many
variables and not every leak is immediately detected. The presence of a leak in the distribution
system is often identified only when it appears on the surface and is reported by a utility
employee or customer. This mode of detection is very valuable. An educated and motivated
customer, as well as a trained field inspector, is an indispensable resource for this mode of
detection. Appearance of a leak may take a variety of forms from the subtle to the spectacular.
The ways that leaks may be recognized and reported in the field include:
Suspect Areas - This is perhaps the subtlest of appearances and may go unnoticed for
some time. Educating customers on what to look for sensitizes them to consider
unanticipated moisture as a possible leak and report it. The leak may manifest itself as a
moist or discolored area, especially if it is in the vicinity of the water main, service line or
meter. In some climates, this indicator may not be standing water but rather may be an
unusually green patch especially during dry summer months.
Surface Flows - Water appearing on the surface of the ground in quantities sufficient to
cause a flow may portend a leak that has become large enough to make it to the surface in
such a quantity that it is not being absorbed by the surrounding soil or evaporating.
Flows around hydrants can often signal an improperly seated foot-valve or a damaged
connection. While such flows may be from naturally occurring ground water flows, they
may also need special attention from the water provider to identify their sources.
Typically, a simple chlorine (or fluoride) residual test can determine if the flow is potable
Review 4-5
-------
water. Flows in culverts or entering streambeds may not be immediately recognized as
leaks from the public water system as one expects to see flowing water in these locations.
Reduced Water Pressure - Customers are highly sensitive to changes in their service and
expect their water utility to provide excellent water quality and reliable flow. If a leak
has grown large enough, the system might experience a notable loss of pressure. While a
very gradual loss of pressure over time is hard to recognize, increased reports of
"unacceptable" pressures within an area should be a signal the leak may have reached
actionable levels.
Flow Disruption - Probably the most dramatic form of water loss detection is due to the
sudden failure of the main and loss of service. The provider is typically notified of such
occurrences as they tend to be highly visible and may become a public safety issue. This
water loss has moved from the category of a leak to being a true system failure that has
the potential to impair both the water quality and flows. System operators are often
aware of such failures, even if its exact location is unknown, through loss of system
pressure or storage tank level. If not located in a visible area, larger water main failures
may be reported through user complaints of low pressure and/or discolored water.
4.2.3 FLOW MONITORING
One of the major methods of water loss detection is through system measurement. Water loss
may be detected from routine water meter reading and billing computations by the customer
service department. System water loss may also be recognized by the customer when higher
than expected water bills are received if the leak is in the service line on the customer's side of
the water meter. Water loss identification through metering requires the comparison of water
volumes recorded by the collective customers' meters over a specific period of time to the water
volumes discharged from the treatment facilities or the volume passing through system zone
meters over this same period of time. Such comparisons require training, communication and
management attention. Customer service billing activities and system flow monitoring
operations are not compared in many utilities as each set of data serve a unique and different
purpose. Management must provide the leadership and incentive for these comparisons to be
made and the result analyzed for metering to become an effective tool in the water loss
identification.
Water volume measurement may also be the result of a program established to meter flow
volumes in isolated portions of the system to actively seek out real water losses. Such an
approach subdivides the distribution system into areas that can be isolated from each other and
Review 4-6
-------
whose flows can be measured with appropriate metering. The size of each District Meter Area
(DMA) is a function of the system configuration, size of the labor force, hydraulics of the area
and customer demand patterns. Typically a DMA will serve 1,500-2,000 connections. Once a
DMA has been identified, the flow is metered with an installed or portable water meter to
measure the total volume of water supplied to the area. Reading the DMA master meter during
late night periods (2:00 am - 5:00 am) can provide indications of higher flows than would be
expected during this early morning period. DMAs with suspiciously high flow levels can then be
further refined through step-testing to better characterize the water loss in this area.
Step-testing further subdivides the DMA under consideration by measuring flows in individual,
isolated laterals of the area. This testing starts at the end of the system and successively works
backwards towards the head of the area where the area meter is located. A comparison of the
measured results, coupled with knowledge of the area, can flag laterals in the system showing a
higher than expected flow rate and one where leak detection is most likely.
Step-testing can use either permanent or temporary metering. Permanent meters have the
advantage of already being in place, easily accessible with historical usage data based on past
billing to verify their calibration. Key points in the distribution system, which will be needed for
routine analysis of system flows, are good locations for permanent meter installation. Such
meters can be routinely read either manually or via a supervisory control and data acquisition
(SCADA) system. Frequently these meters are used to monitor flows throughout the system but
can double as water loss meters when used as part of a water loss management program.
Permanent water meters require a substantial capital investment to install and maintain. Unless it
can serve dual and repetitive functions, permanent DMA meters may be financially infeasible for
some systems.
Alternatives to fixed meters are temporary portable meters. Many of these meters are available
as "clamp-ons" that measure the volume flow rate through a water main by being attached to the
outside of the main. The obvious advantages of this type of temporary meter is that the integrity
of the pipeline system remains intact and the meter can be placed and then relocated to another
spot when measurements are completed. Further, if the water main is readily accessible (e.g.,
meter vault, pressure release valve (PRV) site, air release vault), the need to excavate the line is
avoided. Care must be taken to understand the accuracy of clamp-on meters and their sensitivity
to the flow rate thresholds when used to detect water loss.
Several general categories of temporary flow meters are shown in Table 4-2. Each of these
sensor types requires a processor to integrate the signals and translate them to a liquid flow rate.
It should be noted that these meters could be used for single point readings or as part of a
Review 4.7
-------
remote-read, long term monitoring scheme. A Supervisory Control and Data Acquisition
(SCADA) system can be a highly effective communication and processing network for such
metering.
4.2.4 LEAK DETECTION AIDS
Perhaps the most common form of water loss leak detection is from proactively searching for
leaks in the field. Searches must be planned carefully and conducted in a disciplined manner for
the results to be meaningful. These searches use a wide variety of tools to aid in discovery of
potential system leaks. Most of these leak detection approaches locate and quantify the leaks by
observing the presence of, or change to physical property (noise, temperature, etc.) that occurs
only when a pipe leaks. Understanding the strength and weaknesses of each approach can help
the operator select the best application for the system. A number of these technologies are
discussed below.
The integrity of underground infrastructure is always difficult to evaluate. A large part of the
capital investment of a public water utility can be attributed to its underground assets. Due to
low visibility they are easy to forget, hard to assess but absolutely critical to the sustainability of
the utility. The utility should actively search for leaking water mains, evaluate the magnitude of
these leaks and have a program in place to prioritize and address leaks. Since a direct
measurement of the leak's flow rate is difficult, secondary indicator measurements that are
frequently easier to apply can be used as surrogates. These secondary measures typically fall
into a number of techniques: acoustic, thermal, electromagnetic and chemical. Each technique
has its own strengths and weaknesses. Not all leak detection techniques can determine where the
leak is located and even fewer can assess the magnitude of the leak.
Some leak detection methods discussed below may require dewatering of pipes to install sensors
or equipment. When using a leak detection method that requires dewatering, it is likely that
disinfection and testing of the dewatered section will be required before the water line is put back
into service. This ensures that no source of contamination has been introduced to the water
supply by the testing procedures. Contact your state or primacy agency for their requirements
for disinfection and testing after dewatering pipelines.
Review 4-8
-------
Table 4-2. Temporary Flow Meter Types
Meter Type
Ultrasonic
Magnetic
Induction
Operating Principle
Utilizes "time-of-flight"
measurements of wave
propagation (Doppler shift) of
an applied ultrasonic signal to
determine the fluid velocity.
Relies on the conductive
properties of the liquid. The
flow passes through a
magnetic field producing a
voltage difference over the
cross-section of the flow area
proportional to the average
flow velocity. By knowing the
liquid conductivity, and the
magnetic field strength, the
flow velocity can be
calculated.
Notes
Advantages
Disadvantages
Accuracy
Cost
Advantages
Disadvantages
Accuracy
Cost
Highly accurate flow
detection for stable flows.
Not accurate in regions
of temperature change.
Requires 1 100-
240VAC, 50-60 Hz power
source.
+/- 1%
Capital: $3,000-$4,000
Relatively inexpensive
and accurate across a wide
range of flow rates.
Requires 1 100-
240VAC, 50-60 Hz power
source.
Must be inserted in-line
(flanged connections).
+/- 0.5%
Capital: $2,500-$4,000
4.2.4.1 Acoustic Devices
Two distinctive audible noises are produced as pressurized water breaches the water main. The
first noise is produced by a Shockwave created when the water is forced through the opening.
(The differential pressure between forcing the water out of the pipe must usually exceed 15 psi
for substantial audible sonic waves to be generated and therefore detected.) These sounds are
normally in the 500 to 800 Hz range and are propagated through both the pipe and the water.
These sonic waves travel substantial distances in the pipe and therefore can be detected for
hundreds of feet from the actual break site. The second noise generated is typically in the 20 to
250 Hz range and is produced by the impact of the water stream on the surrounding pipe bedding
materials, as well as water circulating through the cavity caused by the leak (Hammer and
Hammer, 2003). These sound waves travel through the ground and are therefore restricted to a
much shorter distance of travel before they are attenuated and can no longer be identified from
the background noise. These lower frequency sound waves can be used to help spot the exact
location of the break as the operator continues to listen along the pipe. There are many sounds
carried by the pipes such as the noise of water moving through and around various
appurtenances, to pumping sounds to street noises. Every distribution system has its own unique
Review
4-9
-------
acoustic signature that changes from one point in the system to another. It takes time to
recognize and understand the various noises that are part of normal system operation. Acoustical
instruments are designed to assist the operator in detecting and identifying those sounds that are
most characteristic of a main water loss. An experienced operator with distribution system
operating knowledge is a key factor in effective leak detection.
Listening Rods/Sticks
Listening rods are among the simplest and oldest form of leak detectors in use. A listening rod
aids the user in hearing the noises that water makes as it is forced from a pipe. The listening rod
in its simplest form is a steel rod, several feet in length, with an earpiece at one end to help block
out outside noises. The tip of the rod is placed on the pipe if exposed, or more frequently on a
hydrant or valve stem. Sounds from the water loss site are transmitted through the steel rod to
the listener. If the user is in close enough proximity to the leak site, the lower frequency ground
waves can also be detected. It takes operator practice and skill to successfully use a listening
rod, but it is an effective and inexpensive tool. Table 4-3 provides more detail regarding
listening rods/sticks.
Review 4-10
-------
Prevalent
Application
Strengths
Weaknesses
Set-up Time
Average on-station
time
Capital Cost
Photo
Notes
Table 4-3. Listening Rods/Sticks
Leak Detection
Simplicity
Rugged, no mechanical parts, no electronics
Requires no calibration
Requires substantial practice to use well
May be hard to differentiate between normal and leak noises
in noisy systems
Hard to pinpoint location of leak
1-2 minutes - time it takes to apply to top of hydrant or open
and a valve box and expose top of isolation valve
2-5 minutes (varies) - highly dependent upon skill of operator
and familiarity with the sounds of the system
$15-$25, w/case $50 - $60
Ref:www.pollardwater.com/pages_product/P679sonoscope.asp
The experienced water system operator can become very adept
detecting smaller water leaks using a simple contact listening
device. However, the detection of larger leaks and the location
of any leak can be very difficult.
Geophones
The geophone is a completely mechanical listening device that operates much like the
physician's stethoscope. A set of listening tubes extends from the operator's ears down to
listening-heads placed directly on the ground above the pipe to be evaluated. An experienced
operator, moving the heads along the pipe, can become adept at detecting leaks. The stereo-
effect of the two listening heads permits the operator to accurately locate the site of the breach.
While the simplicity of the device makes it very rugged and inexpensive to operate in the field, it
can miss some sounds that are traveling in the pipe and water system. Leakage sounds for non-
metallic pipe or the low-frequency sounds of water impacting the surrounding bedding do not
travel well through the pipe but rather travels through the ground. Geophones are best used for
Review DrafI
4-11
-------
detecting leak sounds that are propagated largely through the ground. Table 4-4 provides more
detail regarding geophones.
Table 4-4. Geophone Leak Detection
Prevalent
Application
Leak detection and location
Strengths
Simple and ease of use
Rugged construction
Requires no power
Weaknesses
Requires operator experience to become proficient
May miss some classes of leaks
Pipeline route needs to be marked so that operator can
place phones directly above line
Set-up Time
5-minutes - some unpacking and assembly on first test
required.
Average on-station
time
2-5 minutes for leak detections with another 5-20 minutes
for leak location.
Capital Cost
$350 - $400
Photo
Ref: http://www.heathus.com/InfoCenter/geophone.pdf
Notes
Once a leak sound has been detected, the two listening
heads are placed on either side of the suspected leak site.
By careful listening to the difference in sound intensities,
the experienced operator can isolate the general area of the
leak.
Hydrophones
There are a wide variety of acoustic listening devices that use a hydrophone (piezoelectric crystal
materials that produce an electric signal in response to acoustic impacts) to pick-up the sounds of
leaking when placed on the piping system or in some cases on the ground above the pipe. These
instruments are enhanced versions of the listening rod coupled with a battery powered sound
amplifier to enhance the sound being transmitted. Testing on the ground along the pipe must
augment the static listening to the pipe leak sounds to accurately locate these leaks. Many
Review Draft
4-12
-------
devices are also equipped with frequency range filters to permit the operator to filter out non-
leak causing noises and better concentrate on noises coming from the pipe in the frequency range
most indicative of a leak. A number of more sophisticated acoustic leak detectors have added
various degrees of digital processing to the amplification systems. These detectors aid the
operator by providing digital and graphic readouts of sound strength to assist in identifying leak
locations. Many instruments attempt to correlate the amplitude of the leak noise to leak flow
rates to provide the operator with an indication of leak magnitudes.
While the hydrophone greatly adds to the ability to detect leaks, operator experience and
judgment is needed to understand the testing intervals that are needed along various sections of
the system. The distance that leak sounds will travel and can be detected depends on both the
pipe material and diameter. Table 4-5 provides an indication of how these detection distances
vary and Table 4-6 provides more detail regarding hydrophones.
Table 4-5. Leak Noise Travel for Distances in Distribution Mains*
(for a 5 gpm leak @ 60 psi)
Type of Pipe
Iron Pipe
AC Pipe
PVC Pipe
Pipe Dia.
6"
12"
24"
6"
12"
24"
6"
12"
24"
Typical Sound Travel Distance
1000 -1200 ft
800 -1000 ft
600 - 800 ft
800 -1000 ft
700 - 900 ft
400 - 600 ft
400 - 600 ft
200 - 300 ft
100 -150 ft
Leak Noise Travel Distances in Service Lines
(for a 2 gpm leak @ 50 psi)
Copper Tubing
Galvanized Steel Pipe
"Poly" Plastic Tubing
600 -1000 ft
800 - 1200 ft
50 -100 ft
*Courtesy Subsurface Leak Detection, Inc., 4040 Moorpark Avenue, Suite #104,
San Jose, CA 95117
Review Draft
4-13
-------
Table 4-6. Hyrdophone Leak Detection
Prevalent
Application
Leak Detection, location and quantification
Strengths
Numerous operator aids to enhance leak detection and
location
Can better fix location of water loss
Some detection heads can be designed to optimize use on
non-metallic pipe
Weaknesses
Requires some operator training
Requires experienced operator to interpret what is being
heard
Equipment needs moderate care in the field
Higher cost
Set-up Time
5-minutes - some unpacking and assembly on first test
required. Time it takes to apply to top of hydrant or open a
valve box and expose top of isolation valve
Average on-station
time
2-5 minutes for leak detections with another 5-20 minutes
for leak location.
Capital Cost
$1,200 - $4,000 depending on features
Photo
Ref: http://www.subsurfaceleak.com/PDFs/LD-15_brchr.pdf
Notes
Specialized listening heads are available to connect directly
to the pipe (valve or hydrant) or for use on the ground above
the pipeline.
Review Draft
4-14
-------
Acoustic Fiber Optics (AFO)
There has been some recent research using listening devices either a fiber optic cable [Higgins
and Paulson, 2006] or hydrophones arrayed along an insulated copper cable that are streamed
into the water main at a valve or other fitting. Primarily used in larger transmission mains, the
listening devices are placed as a permanent or quasi-permanent installation in key water mains
that are critical to the reliability of the system. The cable detects sounds that are transmitted to a
digital processing and recording device. Circuitry in the digital processor filters-out random and
system noises, focusing on noises most frequently associated with pipeline breaks. Once a break
is detected, its location along the cable is provided to the operator.
Acoustic Fiber Optics (AFO) are frequently used with larger diameter prestressed concrete
cylinder pipe (PCCP) due to the distinctive "ping" that is made when a pre-tensioning wire
breaks. A profusion of such wire breaks over a relatively short period of time may be a
precursor to a rupture of the pipeline in that area. These systems when properly installed and
monitored can be an effective element in an overall water loss management program. AFO
installation requires dewatering of the distribution system site, but not necessarily the complete
dewatering of the entire system. Cable lengths exceeding 40 km have been used. Cable receiver
and processing equipment must be provided with an external power source for continuous
operation but lend itself to SCAD A interface.
A laser is used to project light down the fiber and a data acquisition system monitors reflections
generated by the acoustic activity in a pipeline. The entire fiber cable acts as a sensor so in
effect, the sensor is never further than a pipe diameter from a pre-tensioning wire break. An
advantage of the system is that no electronics are placed in the water flow, so monitoring system
noise is nearly eliminated. Table 4-7 provides more detail regarding AFO cables.
Review 4-15
-------
Table 4-7. Acoustic Fiber Optic Cable
Prevalent
Application
Detection of small leaks before they become major. May be
a good approach for exceptionally critical mains that cannot
be taken out of service to repair main failures or major
leaks.
Strengths
Provides long, continuous record of main integrity.
Can be highly accurate in detecting and locating water
leaks.
Can track growth of leak site size to accommodate
economical repair schedule.
May not have to be dewatered, but pressure must be
removed to place the cable.
Weaknesses
Requires unidirectional flow to prevent cable from
becoming entangled in valves and fittings.
False positive and negative readings.
Set-up Time
12-18 hours installation time depending on size and
complexity of main.
Average on-station
time
30-60 days. Can also be set up as a permanent in situ
system listening for changes in the main noises that may
indicate the formation or growth of water loss sites.
Costs
Typically a contracted service, equipment not owned by the
utility. Service contract placement / removal costs of
$2,000 - $10,000 plus monitoring costs of $15-$25 per foot
of main. Utility must also dewater line and open access pits.
Photo
Ref: http://www.puretechnologiesltd.com
Notes
Many of these systems are proprietary and may only be
contracted as an occasional or ongoing service. Cost
includes monitoring (active listening) and analysis by the
contractor over an extended period of time with periodic
reports of findings. Installation may require disinfection
and testing before the pipeline is placed back into service.
Review
4-16
-------
Electromagnetic Field Detection
Electromagnetic (EM) field detection is a proven proprietary electromagnetic inspection
technology for evaluating the current condition of pre-stressed concrete cylinder pipelines
(PCCP). Owners of water pipelines can use EM technology to identify distressed pipe sections
within their infrastructure, which allows them to target their maintenance, repair and replacement
programs. Once a pipe is dewatered, EM equipment can be deployed to locate and quantify
existing wire breaks along individual pipe sections.
A mobile energy head generates an electromagnetic field inside a PCCP and measures the
changes within this field caused by broken wires. By providing information on the number of
broken wires in each pipe, EM detection enables the most effective remediation strategy to be
put into action. This process is often used as a first step in a long-term management program for
pre-stressed pipelines. Once the survey is completed and the current condition of the pipeline is
determined, a long-term acoustic monitoring program can be instituted. This monitoring
program, in conjunction with a GIS-based structural risk management program, can ensure the
long-term integrity of the asset. Table 4-8 provides more detail regarding EM field detection.
Review 4-17
-------
Table 4-8. Electromagnetic Field Detection
Prevalent
Application
Similar to acoustic monitoring, electromagnetic field
detection is a technique for surveying, mapping and
evaluating the integrity of PCCP pipe.
Strengths
Generates record of PCCP water main integrity.
Non-destructive test can spot broken wires before they
appear on the surface.
Weaknesses
Pipeline must be dewatered.
Pipeline may have to be disinfected and tested before
being placed back into service.
Interference from adjacent metallic pipelines may occur.
Set-up Time
24-48 hours depending on size and complexity of main,
time to dewater main, time to excavate service pit at both
ends.
Average on-station
time
Set-up time: Requires that line entry and exit points be
uncovered, line dewatered and line opened. Preparing the
line, inspection and equipment insertion can take 1-2 hours.
The inspection takes about 15-min / 1,000-ft of water main
to be inspected (assumes straight, unencumbered path).
Capital Cost
Actual inspection and analysis costs average $15,000-
$30,000 / mile of pipeline to be inspected (exclusive of the
on-site work required to prepare the pipeline for inspection).
Process is proprietary and must be contracted.
Photo
Ref: http://www.puretechnologiesltd.com
Notes
A two-tier analysis is typically provided. A qualitative
analysis of the data takes about 2-days to return to the utility
and permits immediate repairs as needed before line is
placed back into service. A longer, 30-day detailed analysis
is then provided the utility.
Review
4-18
-------
Data Loggers
Data loggers are a modification of an acoustic leak noise detection recording. Data loggers
combine a listening head with a digital recorder into a single sensor that can be attached to the
system and left in place to operate over an extended period of time. At the end of the testing
period, the loggers are removed and their time-marked data downloaded to specialized leak
characterization and detection software for analysis. The frequency of sampling and recording
sound intensity information is preset by the operator and can range from once per millisecond to
once per minute and can remain in place for several days, limited only by the data storage
capacity of the unit. More sophisticated loggers can be set to turn on and turn off, sampling only
during the quieter, low-flow hours. Some models of data loggers contain radios that will
download their stored data when queried, resetting themselves for follow-on recording. This
data transmission feature is useful for extended period measurements when the change in
identified signals can be used to confirm and quantify water loss magnitudes. Data loggers can
be an effective, low-cost method of taking continuous measurements, especially when nighttime
logging is desired.
Data loggers are most successful when used for leak detection on cast iron, ductile iron, steel,
concrete and transit pipe. Leak detection in PVC needs longer run times. Table 4-9 provides
more detail regarding data loggers.
Review 4-19
-------
Prevalent
Application
Strengths
Weaknesses
Set-up Time
Average on-station
time
Capital Cost
Photo
Notes
Table 4-9. Data Loggers
Leak noise sound intensity sampling and recording.
Provides long-term record over several days.
Requires no on-site operator.
May be used with other loggers to quantify and locate
leaks.
Requires limited operator training to set logger in field.
Subject to easy theft unless protected.
20-30 minutes, including time to set logger sampling rate
and recording period. Required revisit to download and/or
remove data logger.
1-3 hours depending on pipe material. PVC requires
longer data collection periods.
$19,000 - $21,000 (includes factory training).
Ref: www.subsurfaceleak.com
These devices are most accurate for leaks in pipes < 16" and
are more difficult for leak detection in pipes > 36". For the
most accurate leak locating, more than a single correlation
should be used for each leak detected.
Leak Noise Correlators
It is not unusual for larger leaks to generate both lower frequency and lower noise intensities
than recently formed, smaller leaks. Smaller pipe penetrations may result in higher discharge
velocities that produce a louder, more characteristic sound for the same pressure differential
across the pipe than older larger pipe breaches. These larger leaks can therefore be even more
difficult to detect and locate, especially in portions of a distribution system that are generating a
wide range of noise profiles (Lahlou, 2001). Leak noise correlators are computerized listening
devices that utilize two or more highly sensitive sound detection sensors placed on each side of
the suspected leak and transmit (or connect by hard-wire) to a computer that filters and calculates
Review Draft
4-20
-------
a leak's location relative to the sensor array. Sound from a water loss site travels at a fixed speed
which depends on the size and material of the pipe. The filtering and digital processor of the
correlator is able to identify and delineate sounds typical of water breaks. Comparing the arrival
times of these sounds as detected by each of the two sensors, the computer of the leak noise
correlator can integrate their arrival times and thereby infer the distance that the water loss site is
from the listening heads. The result of this integration is then displayed to the operator. The
leak noise correlator with two fixed microphones is able to mimic the action of an operator with
a single microphone moving back and forth across the water main listening for the quality and
amplitude of a break sound. Faster and more accurate leak locations are possible using a
correlator in the hands of a trained and experienced operator. Some leak noise correlators are
wireless and provide the flexibility needed to accurately locate water loss sites along highly
inaccessible routes. Table 4-10 provides more detail regarding correlators.
Table 4-10. Leak Noise Correlators
Prevalent
Application
Water loss detection and site location.
Strengths
Accurate delineation of water loss noises from complex
sonic background.
Accurate location of water loss site.
Greatly reduced time, especially along a highly
inaccessible route.
Can locate leaks in PVC and DPE pipe.
Weaknesses
Requires factory training.
Requires moderate care in the field.
Set-up Time
10-20 minutes.
Average on-station
time
30-60 minutes but may be longer if attempting to detect
during periods of high demand.
Capital Cost
$20,000 - $32,000 dependent on ancillary equipment
(typically includes factory training).
Photo
Ref: www.utsleak.com
Notes
Not unusual for the accuracy of leak locate to be better than
1m/100 meters.
Review Draft
4-21
-------
4.2.4.2 Thermal Detection
Unlike acoustic devices that detect a property of the leak, thermal detection devices look for the
temperature differences in the surrounding ground caused by saturation due to the leaked water.
Thermography
Thermography measures the infrared radiation (heat) emanating from the ground. Areas along a
water main in which a water loss site is active will frequently exhibit saturated conditions just
below the surface that may or may not be apparent on the surface. These saturated zones tend to
be somewhat warmer than their surroundings in the cooler winter months. Conversely, these
areas may appear cooler than their surroundings in the warmer summer months. Infrared
measurement of the general area can help detect these areas of temperature differentiation and
locate the water loss site. The operator can use simple hand-held infrared meters with digital
temperature gauges to locate the general area to excavate for the leak. When used on a larger
scale, whole-site thermography has been successful at photographing temperature variations and
locating leaking below slabs, pavement and even buildings. Infrared measurement locating is
most frequently used in conjunction with other methods of detection to better locate the best
potential excavation sites. Table 4-11 provides more detail regarding thermography.
Review 4-22
-------
Table 4-11. Thermal Water Leak Detection
Prevalent
Application
Strengths
Weaknesses
Set-up Time
Average on- station
time
Capital Cost
Photo
Notes
Water loss site locating.
Can narrow the general area of leak site locating.
Simple to use.
Relies on temperature variations which may not be very
large.
Gives no indication of the size of the leak.
Leaks may be masked by groundwater.
5-10 minutes.
15-30 minutes depending on ground conditions.
$150 - $10,000 - hand-held infrared meters are fairly
inexpensive but whole-site thermography can become
expensive and is probably best accomplished through a
knowledgeable contractor.
Visible photo on left and thermal photo on right. The water
leak from the transmission main shows up as a dark blue
area.
Ref: www.thermal-imaging-survey.co.uk/archive/pipeline.htm
While thermal leak detection techniques can be used for
local applications, it also can be used in much larger
detection areas such as for long runs of transmission mains.
Review Draft
4-23
-------
4.2.4.3 Electromagnetic Detection
Various forms of electromagnetic detection devices have been developed for use in locating
busied utilities, especially pipelines. Some of these same technologies are being extended to
help identify leaks in these pipelines.
Ground Penetrating Radar (GPR)
GPR, also known as ground probing radar, subsurface radar, georadar, or earth sounding radar,
locates and evaluates subsurface leaks without the need to expose them (Eyuboglu et al). Most
GPR units operate by transmitting electromagnetic waves (125 MHz to 370 MHz) into the
ground that subsequently bounce off of subsurface objects and return to the receiver head of the
unit. The returned signal is processed into a picture of subsurface objects including plastic pipes,
rocks and voids. Water leaking from a pipe usually can be detected and the exact location of the
pipe breach can be identified real-time as the operator moves the lawn mower-sized unit along
the length of, and back and forth across the pipeline. Enhanced signal processing is being
developed to help the operator refine the investigation. Table 4-12 provides more detail
regarding GPR.
Review 4-24
-------
Table 4-12. Ground Penetrating Radar
Prevalent
Application
Water loss site detection, locating and quantification.
Strengths
Relatively independent of pipe material - can detect leaks
in metallic, concrete and plastic pipes.
Can detect leaks in any pipe >1".
Compact unit easily transportable.
Moderate operator training and support are required.
3-4 m depth detection possible.
Weaknesses
Requires access to route along top of pipeline.
Takes training and experience to accurately delineate leak
detections.
Definition can be highly dependent on pipeline bedding
and groundwater conditions.
Set-up Time
10-20 minutes, assuming site is clear of inhibiting structures
or vegetation.
Average on-station
time
1-3 hours depending on the length and accessibility of line
to be inspected. Pipeline needs to be located and marked
prior to radar scan to improve leak detection results.
Capital Cost
$15,000 - $31,000 depending on the size and mounting of
the radar head.
Photo
Ref: www.geodetic.com.au/ categoryl541_l.htm
Notes
Only moderate operator training and support are needed to
operate equipment and locate pipes but significant
experience can be required for the detection of water leaks
using ground-penetrating radar. While GPR quickly and
accurately detects the pipeline, considerable interpretation is
frequently required to see the signature of a leak.
Review Draft
4-25
-------
4.2.4.4 Chemical Detection
Chemical detection techniques rely on the introduction of a detectable gas into a dewatered line
or a liquid to the water. If detected outside of the pipe, it is an indication of a breach in the pipe
wall. Due to the restrictions on products that can be used in conjunction with potable water
supplies, these techniques must be used with forethought and great care. The local drinking
water regulatory agency should be consulted before considering chemical detection.
Tracer Gas
Also called "Gas Sniffing", is an emerging leak detection technology that was developed by the
petroleum industry as a passive approach to detecting pipeline leaks. It has some applicability in
the potable water sector, especially in those applications where the line can be taken out of
service, dewatered and tested. The technique requires the injection of an inert gas, typically a
5% hydrogen-nitrogen mixture into a pipeline to be tested. Electro-chemical sensors are then
used to detect the presence of hydrogen gas in the air just above the ground atop the tested
pipeline. Once the detectors are calibrated for the ambient levels of free atmospheric hydrogen
gas, they can be used to detect and locate main leak sites. In many cases the intensity of the
detected hydrogen will provide indication of the size of pipeline breaches. The most frequent
configuration is a hand-held detection unit (USAGE, 2001). Some experimental work has been
attempted using gas detection technology on operating systems. Due to the sensitivity of some
waters to the nitrogen carrier gas used in this method, this technique has only limited application
for some systems that must remain in operation. Table 4-13 provides more detail regarding
tracer gas detection.
Review 4-26
-------
Table 4-13. Tracer Gas Detectors
Prevalent
Application
Water loss detection and site location.
Strengths
Non-destructive testing approach.
Facilitates location of multiple leak sites.
Not dependent on pipe material, water pressure or physical
shape of leak.
Can be used with either operating or dewatered lines but
dewatered application results in greater sensitivity.
Weaknesses
Some systems may have to be dewatered to use.
Needs careful calibration of sensors to achieve usable
accuracy.
Requires extensive operator training.
Sensitivity may be somewhat weather dependent.
Set-up Time
8-12 hours depending on the dewatering and preparation time
required.
Average on-
station time
1-2 days depending on complexity and geometry of the section
to be tested.
Capital Cost
$16,000-$18,000 depending on number and type of equipment
attachments.
Photo
Ref:
www.schoonoverinc.com/products/Leak%20Detection/leak%20detection.htm
Notes
Gas detection methods are more accurate at detecting the
existence of a leak in the pipeline than at locating the position of
the leak due to the multiple paths that the escaped gas may take
to the surface. It is very difficult to quantify the magnitude of
the leak using this method. The procedure may also require
disinfection and testing before the pipeline is placed back into
service.
Review Draft
4-27
-------
Tracer Liquids
Although infrequently used, leak detection is sometimes possible with the use of liquid tracer
markers. A water system operator may be faced with having to determine if the water that is
seen on the surface of the ground is coming from the public water system. Such an analysis can
be facilitated by injecting a conservative (decay constant of zero) marker into the water system
and then testing for this marker in the surface waters. A number of markers can be used
depending on the nature of the water systems. Chlorine, although not technically considered a
conservative marker, is easily injected and detected. It provides a marker for those systems that
do not maintain a chlorine residual. Fluoride is another chemical that can be injected into either
chlorinated or non-chlorinated system as a marker. The appearance of fluoride in the surface
waters is then a positive indicator of a water loss site from the water main, although exact
location and magnitude of the leak are not highly enlightened by the process. A number of
manufacturers market fluorescent dyes for use in public water systems that can be injected into
the distribution system and in very low concentrations are invisible to the eye in natural light, but
which fluoresce under ultraviolet (blacklight) light. The dyes should be NSF Standard 60
Certified for use in a potable water system. Quantification of water loss can be attempted with
fluorometer measurement of the marker dispersion of the marker. This technique is highly
susceptible to interferences from the soil complex and the amount of groundwater present. Table
4-14 provides more detail regarding tracer liquid leak detection. It should be noted that addition
of any tracer, including chlorine and fluoride, may be subject to state drinking water program
approval.
Review 4-28
-------
Prevalent
Application
Strengths
Weaknesses
Set-up Time
Average on- station
time
Capital Cost
Photo
Notes
Table 4-14. Tracer Liquid Detectors
Water loss detection.
Can affirm the existence of a breach in the distribution
system from its appearance on the surface.
Not very accurate method for determining location of
water loss site.
Gives little information on the magnitude of the flow
Propensity for false negatives.
May not be approved for use by local health agencies.
1-3 hours for preparation of field injection site.
1-3 hours depending on speed that marker diffuses in line
and migrates to the surface.
$100-$300 mainly a function of the injection pump and
system connection costs.
i$l'lii!iiilfel;.IueSHiiirtl
" 5ii t*nr **;~*11
h.i'^SjA.teL
i ' _ iri "j
i
i
** I*J.T 'T-V*
*- ?.
Ref: www.usabluebook.com
Dye tracer studies in water systems require metering into the
stream to maintain levels low enough not to be
objectionable to water aesthetics but of great enough
concentration to be detectable in area where leaking is
suspected. More widely used in the wastewater sector.
4.2.5 LEAK LOCATING SERVICES AND OTHER POTENTIAL SOURCES FOR
EQUIPMENT AND EXPERTISE
It can be expensive and it takes experience to accurately locate leaks using many of the methods
described. For larger municipalities or any system planning to develop a proactive loss control
and monitoring plan it makes financial sense to acquire equipment and train staff to operate it.
Smaller systems might not benefit from making this capital investment and extensive
commitment. There are other options available to smaller systems that might be more feasible.
Review Draft
4-29
-------
It may be possible to borrow or rent the equipment from a nearby water system that has leak
detection equipment or from a rental service. It may also be advantageous for a water system to
contract their leak locating services to other municipalities to help offset equipment cost and staff
training. For smaller systems, periodically hiring a commercial leak locating service may be the
economical choice. Small water systems should talk to their primacy agency or local experts to
learn of the available resources. Funding may also be available from state revolving funds or
other programs for water audits.
4.2.6 PREDICTING PIPE FAILURE
While full analysis is beyond the scope of this document two important concepts should be
introduced in pipe failure prediction and modeling. They are Background and Bursts Estimates
(BABE) and Fixed and Variable Area Discharges (FAVAD).
BABE is a concept that was developed by Allan Lambert in 1993 for the UK National Leakage
Control Initiative. It is used for calculating components of Real Losses based on the various
parameters. For the analysis, real losses on different parts of the infrastructure are characterized
as:
Background leakage at j oints and fittings,
Flow rates too low for sonic detection if not visible,
Reported leaks and bursts (high flow rates with short duration), and
Unreported leaks and bursts (moderate flow rates with duration depending on the method
of active leakage control).
BABE is a statistical model and performs better with larger samples. BABE analysis can be
used for calculating components of Annual Real Losses including UARL, or components of
night flows. Typical burst flow rates are specified at a standard pressure, and are adjusted to
actual pressure using appropriate assumptions for Fixed and Variable Discharge path (FAVAD)
Nl values. The Nl value is a calculation factor based on the piping system.
A hole or leak in a pipe has an expected leakage rate based on the size of the hole, shape of the
hole, and the pressure. The Fixed and Variable Area Discharges (FAVAD) concept introduced
the idea that the leak may increase or decrease with pressure due to the area of the leak changing.
For instance a crack in a pipe may get wider at higher pressures and thus allow proportionally
more water to escape. In the simplest versions of the FAVAD equation the Leakage Rate L
(Volume/unit time) varies with Pressure Nl or Li/L0 = (Pi/P0)N1. Nl values can be calculated
from tests on sectors at night. Values derived for sectors in the UK, Japan, Brazil, Cyprus, USA,
Australia and New Zealand have shown that Nl generally varies between 0.50 and 1.50, with
Review 4-30
-------
occasional values up to 2.5. Small undetectable leaks at joints and fittings typically have Nl
values around 1.50, as do larger leaks and bursts on flexible pipes. Detectable leaks and bursts
on rigid pipes normally have Nl values close to 0.50.
The BABE and FAVAD concepts are used in multiple software packages that help water system
managers assign values to help calculate performance indicators and prioritize pipe replacement
or rehabilitation.
4.2.7 PIPE REPAIR AND REPLACEMENT
4.2.7.1 Pipe Repair Techniques and Considerations
A major center of focus of an effective water loss management program is repair/rehabilitation.
Repair typically depends on trained crews, using the appropriate materials, equipped with the
adequate tools to safely repair leaks quickly and securely. As expensive as repairing a leak can
be, fixing it a second time can more than double the investment in labor and materials while
destroying customer satisfaction.
4.2.7.2 Pipe Repair/Replacement Personnel
A trained and experienced crew that has working knowledge to conduct effective and timely
leak repairs is priceless. The repair approach will depend on the leak and the environmental
conditions in which the repair must be made. If the leak site is the result of small corrosion
pitting or puncture holes, a repair clamp will usually work quickly and well. Leaks that result
from large-hole formation or long cracks may require replacement of one or more sections of the
pipe. For large steel pipe, repair may take the form of in situ welding. Repair crews need to be
trained on a variety of fix approaches.
4.2.7.3 Available Equipment and Materials
It is prudent and common for utilities to maintain a small inventory of parts to support leak
repairs in their distribution systems. An analysis of the leak repair history of the utility can
greatly facilitate the selection of appropriate materials and quantities to stock. Many smaller
operations have found that it is advantageous to reach out to neighboring water utilities that may
have similar repair parts and equipment needs to be aware of what might be available in their
stock in case of an emergency. Finally, for larger scale events, over 30 states have now formed
mutual assistance networks called Water & Wastewater Agency Response Network (WARN)
(http://www.nationalwarn.org) to provide expansive help between water utilities within a state
and in many cases even across state lines. While WARN is primarily for disaster response, a
large catastrophic failure of a major transmission line may require more resources than a PWS
has available and may need assistance from a WARN partner.
Review Draft 4.31
-------
4.2.7.4 Leak Repair Techniques
A variety of technologies are available to repair pipeline leaks depending on their location and
size. Many studies have shown that the most significant portion of leak repair cost and time is
attributed to uncovering the leak site and dewatering. From there, the repair techniques are
relatively easy. For this reason, a growing portion of the leak repair market is centered on
approaches that do not require that the pipeline be uncovered. The following approaches, while
certainly not exhaustive, are meant to provide the user with a representation of the level of effort
and potential costs that may be encountered using such techniques.
Wrapping
Some small pipe leak repairs may be made using a surface wrap depending on pipe material.
Many of these products take the form of a fiberglass cloth impregnated with a resin that is
activated by water. The cloth comes ready to apply and does not require any mixing or
measuring. The application is largely insensitive to pipe temperature at the time of application
and many brands can even be applied under water. Cracked pipes can be wrapped with the cloth
and secured with a pressure sensitive rubber tape. Corrosion holes are typically patched with a
two-part epoxy before being wrapped. Some products are designed for application while the
pipe is under pressure, avoiding the necessity to shut-off the water service. Table 4-15 provides
more detail regarding pipe wrapping.
Review 4-32
-------
Table 4-1 5. Wrapping
Prevalent
Application
Description
Application Time
Average on- station
time
Cost
Photo
Notes
Small holes and short cracks that will not tend to lengthen.
Cloth comes in 4", 6" and 8" widths.
Cloth rolls up to 50' long.
Can be applied to pipe under pressure (< 60 psi).
Patches rated for line service up to 300 psi.
Cure time 30-60 minutes before line pressure can be
applied.
Total application time 1-2 hours.
Patch needs 24 hours to fully set before backfilling water
main.
Typically limited to repairs on pipes 4" and under.
Product must be NSF certified in most states.
Highly variable depending on site conditions:
Traffic conditions & traffic control needed,
Depth of pipe & availability of excavation equipment,
Depth of trench and shoring required,
Trench dewatering,
Availability of new bedding and backfill material,
System Flushing, and
Surface restoration.
$15 - $75 - repair kit, depending on pipe size
with 2-4 hours repair time.
Ref: www.prime-line.net/urethane.html
Works on PVC, copper, concrete, and most metals, plastic
and rubber pipe materials.
Review Draft
4-33
-------
Repair Clamps
Repair clamps are collars that can be fitted around the outside of the pipe to patch the hole or
break. The metal collar contains a partial or full size gasket that is subsequently compressed
onto the surface of the pipe by the clamp providing a pressure tight fitting to stop the leak. Table
4-16 provides more detail regarding repair clamps.
Table 4-16. Repair Clamps
Prevalent
Application
Small holes and short cracks that will not tend to lengthen.
Description
Clamp usually made of stainless steel.
Clamping bolts & nuts made of stainless steel or low
alloy.
Gasket material made from Styrene-Butadiene (SBR) or
Nitrile (Buna-N).
Sized to match the P.P. of the pipe in lengths of 6"- 15".
Application Time
1-hour - Majority of time needed to clean, remove corrosion
from the outside of the pipe and, disinfect the pipe surface in
preparation for clamp placement.
Average on-station
time
Highly variable depending on site conditions:
Traffic conditions and traffic control needed,
Depth of pipe and availability of excavation equipment,
Depth of trench and shoring required,
Trench dewatering,
Availability of new bedding and backfill material,
System Flushing, and
Surface restoration.
Cost
$30-$200 per clamp - depending on type and size.
Photo
Ref: www.subsurfaceleak.com
Review Draft
4-34
-------
Sliplining
Another approach for repairing badly leaking old water mains without having to uncover them is
a process known as sliplining. In this process, the old lines are repaired by pulling a thin-walled
plastic liner inside the old, cleaned pipe to seal its leaks. Sliplining leaves the old pipe intact and
uses it for structural support of the much thinner plastic lining. Once the liner is in place, hot
water is pumped through it, causing the liner to become malleable, expand and tightly seal onto
the surface of the old pipe. In this approach, the original pipe provides the strength and structure
for the pipeline while the liner provides pipeline integrity and improved system performance.
Excavation is only needed at intervals along the pipe to facilitate entry and exit from the line.
There is an added cost of jointing techniques when limited to using short pipe lengths. Poorly
applied grouting can lead to buckling. Sliplining does not work well in pipelines with a lot of
elbows and isolation valve. Table 4-17 provides more detail regarding sliplining.
Table 4-17. Sliplining
Prevalent
Application
Repair of multiple holes in pipeline without excavation.
Description
Grinding, flushing and lining of existing pipelines with thin-
walled plastic linings to seal the line.
Average on-station
time
Like all pipeline replacement, the on-station time is highly
variable. Sliplining may require extensive carrier pipe
preparation and cleaning before lining can begin. Also,
connections of laterals and service connections must be
made following lining. Repair times of 5-10 days per 1,000
foot of pipe to be lined can be expected.
Cost
$120-$135/ft installed (by commercial contractor). The
price includes materials, shipment, line preparation, on-site
pipe fusion, placement & thermal setting and tapping. Price
does not include system dewatering, access pit excavation
(350-500ft) and restoration.
Photo
Ref: www.undergroundsolutions.com
Notes
Sliplining processes require that the lining be re-tapped at
all connections. Several new camera-driven and computer
controlled tapping machines have greatly reduced the time
this re-tapping takes.
Review Draft
4-35
-------
4.2.7.5 Pipe Replacement
Open Trench Replacement
It is not unusual for a repair crew to discover that the section of leaking pipe is far too
deteriorated to repair with the application of a simple repair clamp. In these cases, it may be
necessary to replace one or more lengths of the pipe. While pipe repair replacements are best
done using the same material as the existing pipe, lack of pipe stock or desire to upgrade to a less
corrosive pipe material may dictate that the replacement length be another material. Pipe
couplings and spool pieces to connect the replaced pipe section are readily available. Table 4-18
provides more detail regarding open trench pipe replacement.
Table 4-18. Replacement (Open Trench)
Prevalent
Application
Small holes and short cracks that will not tend to migrate.
Description
Replacement of one or more lengths of pipe (10', 15', 20'
lengths) with new pipe.
Average on-station
time
It is not unusual to expend 60%-80% of the total on-site
time opening the trench, dewatering the work site,
backfilling and repaving the site. The actual pipe
replacement once the trench and bedding have been
prepared is 2-3 hours per pipe length.
Cost
$100-$300 per foot of open trench - depending on pipe
type, size and location.
Photo
Ref: AWWA, "Images on Tap", August 2005
Notes
Flanged couplings and spool pieces may be required to
connect the replacement pipe to the existing system. These
ancillary pieces, sized for the specific pipe being repaired,
are typically maintained by the utility as part of the
emergency repair materials.
Review Draft
4-36
-------
Trenchless Replacement
Aging infrastructure in water systems often means failing joints, leaking valve seals and
corroded pipes, all contributing to substantial leakage from the system. A major obstacle in
repairing these elements is their inaccessibility. Many water mains cannot be effectively
uncovered and replaced when they are located in congested areas and critical traffic arteries.
One approach to replacing these leak-ridden lines is to drag a new pipe through the older pipeline
using a flexible and typically much smoother pipe material (e.g., PVC, HDPE, or Fusible C-900).
The annular space between the new pipe and the old pipe should be grouted to provide added
stability to the new line. If the new pipe is small enough with respect to the old pipe, some
applications have used stand-offs in lieu of grouting. Although the inside diameter of the new
pipeline is usually somewhat smaller than the pipe it replaced, the increased smoothness can
actually result in lower headloss and, naturally, no lost water due to leaking. This technique
requires a long area of space for assembly and joining of the new pipe sections. This limits the
application to pipe sizes of 8 to 96 inches in diameter.
An alternative approach is to destroy the old pipe as the new one is being dragged through it.
This technique can permit the same-sized or even larger diameter pipe to replace the old line.
Pipe bursting can be a reasonable-cost approach to replacing long lengths of the system in areas
where excavation may be difficult or impossible. A "pipe bursting" head is dragged through the
existing pipeline, using it as a pathway. As the head is pulled through, it fractures the old line
making room for the replacement main. The replacement pipe is attached to the bursting head
and dragged into the line in one pass. Trenchless pipe replacement is most effective where long,
uninterrupted runs of new pipe are needed. The approach is less cost-effective in areas where
numerous fittings must be placed on the new pipe as the pipe must be exposed at each location
that such an attachment is needed. Table 4-19 provides more detail regarding trenchless pipe
replacement.
Review 4-37
-------
Table 4-19. Replacement (Trenchless)
Prevalent
Application
Complete replacement of transmission or distribution main.
Description
Fusion welded or restrained joints are required on the
replacement pipeline.
Average on-station
time
Highly dependent on length of pipe to be replaced, ease of
opening end pits and ease of drag through line. 3-7 days are
not unusual for the replacement of 1,000-ft of water main.
Cost
$80-$95 per foot in stalled (by commercial contractor).
Highly dependent on the size of the line to be replaced, the
configuration, pipe depth, and ease of opening end work
pits. Pits required every 500-700 ft of line. Costs do not
include cost of access pit excavation or restoration.
Photo
HP i WFU . VtJatft
Ref: www.premierplumbing.biz/residential.html
Notes
Due to the initial equipment investment and the specialized
training that is needed to operate, trenchless pipeline
replacement is frequently a proprietary process and is
contracted to a specialty company by a utility.
4.2.8 SELECTING REPLACEMENT PIPE
When it is neither economically feasible nor practical to attempt a repair, wholesale replacement
of the deteriorated pipe might be the practical solution. When opting to replace pipe, questions
such as the following should be addressed:
How large is the pipe?
Has there been or will there be growth in the area requiring a larger pipe?
Is the soil type aggressive?
Can significant movement be expected due to poor soils or seismic activity?
Will temporary bypass piping be necessary?
What is the expected pressure?
Review Draft
4-38
-------
How big of a potential is there for surge?
How much of a disruption and inconvenience will replacing the pipe be?
Will design and/or construction be done in house or contracted?
If a different pipe material is selected, will different equipment and training be required
to repair and maintain it?
Administrators must also answer financial questions such as:
How is the work to be financed?
Is the replacement pipe to be a relatively short term solution or is a long service life
required?
The answers to these questions will begin to determine the size and type of material that best
meets the requirements. Tables 4-20 through 4-22 and Figure 4-2 are taken from Deteriorating
Buried Infrastructure Management Challenges and Strategies, EPA (2002) and present material
property criteria and comparisons for different pipe materials to illustrate the array of variables
that will affect performance and costs. Figure 4-2 presents a flow chart decision process to help
decide a course of action as to whether to repair or replace a pipe.
Table 4-20. Comparison of Distribution Size Pipe Materials - Material Properties
Material Property
Tensile strength
Compressive strength
Yield strength
Ring bending stress
Impact strength
Density
Modulus of elasticity
Temperature range
Thermal expansion
Corrosion resistance (int)
Corrosion resistance (ext)
UV resistance
Abrasion resistance
Cyclic resistance
Permeation resistance
Scale & growth resistance
DI
60,000 psi
48,000 psi
42,000 psi
48,000 psi
17.5 ft-lbs/in
441 lbs/ft3
24,000,000 psi
< 150 F
0.07" per 10ฐ F per 100'
Good - w/cement lining
Good - w/polywrap
Excellent
Excellent
Excellent
Yes
Good
PVC
7,000 psi
9,000 psi
14,500 psi
none specified
0.75 ft-lbs/in
88.6 lbs/ft3
400,000 psi
<140 F
0.33" per 10ฐ F per 100'
Excellent
Excellent
Gradual strength decline
Good
Fair
No - solvents &
petroleum
Excellent
HDPE
3,200 psi
1,600 psi
5,000 psi
none specified
3.5 ft-lbs/in
59.6 lbs/ft3
11 0,000 psi
-50 to 140 F under press.
1" per 10ฐ F per 100'
Excellent
Excellent
Yes - w/carbon black
Good
Good
No - solvents &
petroleum
Excellent
Review Dra
4-39
-------
Table 4-21 . Comparison of Distribution Size Pipe Materials - Pipe Properties
Pipe Property
Trade organization
AWWA designation
Diameter range
Pressure range
ID range (8")
Wall thickness range (8")
Weight range (8")
OD nominal (8")
Buoyant (8" 1 00 psi)
Surge allowance
Surge potential (8" 100
psi)
Integrity under vacuum
C-factor
Standard pipe lengths (8")
Type of joints
Max joint deflection (8")
Compatible w/DI fittings
DI
DIPRA
C151
3" - 64"
350 psi
8.425"
0.25"
21. libs/ft
9.05"
No
100 psi
53.6 psi per 1 ft/sec
-------
Figure 4-2. Pipe Rehabilitation Decision Flow Chart.
Source: (EPA, 2002) Deteriorating Buried Infrastructure Management Challenges and Strategies (2002),
Review Draft
4-41
-------
4.2.9 OPERATION AND MAINTENANCE PROGRAMS AND PREVENTATIVE
MEASURES
4.2.9.1 Effective Design and Construction
An effective water loss management program is one that incorporates water loss prevention
techniques over the life cycle of the distribution system. The decision made in the design and
construction phase may impact the operations of the system for years to come. There is a
growing awareness within the water industry of the importance of sound asset management.
Asset management is the awareness to manage all real assets throughout the life cycle of the
public water system. Water loss management heavily depends on controlling the type of assets
that are brought into the inventory and continuously monitoring and addressing issues as they
arise.
4.2.9.2 Material Standards
The selection of material will always be driven by the economics of the project. However, heavy
consideration should be placed on sustainability, durability and applicability of the materials.
Material standards set by organizations such as AWWA, International Standards Organization
(ISO), American Society for Testing Material (ASTM), NSF International, and American
National Standards Institute (ANSI) are developed by incorporating experiences of thousands of
system operators, trade organizations, manufacturers, and other agencies and organizations. For
example, NSF/ANSI 61 focuses on eliminating contaminants or impurities that indirectly enter
the drinking water through treatment chemicals, process media, or components of the drinking
water system. These standards provide the foundation for a utility to establish its own basic
standards of materials that are to be used for all system replacements and extensions.
Establishing and maintaining a utility's "approved products list" helps to assure that the
distribution system will be developed with materials best suited for the community.
4.2.9.3 Design Standards
Standard-setting organizations can provide invaluable service by detailing specific design
approaches that can then be adopted by the utility for their work. Design standards provide the
foundation to guide both the design and construction of a distribution system, which will have
the greatest possibility of maintaining its integrity throughout its operating life. Due to their
strength and durability, many communities use ferrous piping systems (cast iron, ductile iron,
steel, etc.). The design should incorporate corrosion control in ferrous metal pipelines. Water
chemistry and protective coatings can be used to protect the inside of the pipe while a wide range
Review 4-42
-------
of techniques (e.g., poly-wrapping, sacrificial anode placement, impressed current) are available
to protect the outside of the pipe from groundwater and galvanic cell corrosive action.
4.2.9.4 Construction Control
The integrity of the distribution system must be maintained overtime to control and extend the
water loss over its lifetime. The use of pipe crews with experience managing and installing
water distribution systems and regular inspection throughout the process minimizes the
probability of experiencing issues post-construction. The construction of a distribution system is
highly complex, requiring excellence in project management, careful material acceptance,
handling, storage, and exacting installation to provide a piping system which is to carry hundreds
of pounds per square foot of pressure throughout its lifetime. Training can prepare in-house
construction crews for construction challenges that might sneak up. Well-written and enforced
contract language can go a long way toward soliciting and qualifying a contractor. Key to the
process is the utility's project manager and the construction inspector. The inspector should
ideally have extensive experience in pipeline construction using the materials and equipment
chosen for the utility's project. The project manager should document testing of the system
throughout the duration of the construction. This testing typically refers to pressure, performance
and bacteriologic testing.
4.2.9.5 Effective Maintenance
An effective water loss management program should establish a maintenance program sensitive
to minimizing water loss through proactive action. Once a distribution system has been properly
constructed and placed in service, routine maintenance should be conducted to monitor the
system's performance and identify repairs/rehabilitation as needed. Ongoing maintenance will
maintain the public water system operating at optimal performance and maximize the full life
expectancy of the system.
4.2.9.6 Corrosion Control
Several types of very effective corrosion control systems must be maintained if they are to
continue to protect the pipe system. Impressed current systems utilize an active direct current
(DC) that is impressed onto the pipeline making it cathodic and protecting it from corroding.
This current (10-50 amps, 50 volt) is provided via buried electric cable from an AC/DC rectifier,
receiving power from the area electrical system. The anode of the system is a buried probe that
will corrode over time. Properly sized impressed current cathodic protection (ICCP) systems are
highly effective at preventing corrosive leaks in the system. ICCP systems must be maintained
to assure their proper and continued operation. Both the rectifiers and the anodes of these
Review 4.43
-------
systems must be routinely inspected. If either fails to perform, the pipeline will become
unprotected and may be exposed to failure due to pipe corrosion.
Sacrificial anodes (usually magnesium) can be used for effective corrosion control. In these
systems the anode bags are buried in the ground close to the pipeline and directly wired to the
pipeline. The sacrificial anode will corrode more readily than the ferrous material pipeline,
providing a current flow to the pipe making it cathodic and protecting it. These anode bags must
be inspected routinely (most easily with a multimeter probed to the bag to measure the voltage
and current flow) to assure their continued integrity. Once a bag is expended, it must be
replaced.
Similar to the protection of the outside of ferrous pipelines from the corrosion due to water in
contact with the pipe, the inside of the pipeline that is naturally in contact with the water may
also suffer corrosion and need to be protected. Corrosion of pipes can be the result of the water
quality characteristics (e.g., pH, alkalinity, biology, salts and chemicals). Corrosion is
principally controlled by the pH, buffer intensity, alkalinity, and concentrations of calcium,
magnesium, phosphates, and silicates in the water. Corrosion inhibitors can be added to the
water as part of the normal water quality operations to reduce corrosion. These inhibitors can
reduce the potential for the metal surface to be under the influence of an electrochemical
potential by producing an inhibiting layer between the water and the pipe material. (CDC, 2007).
4.2.9.7 Valve Exercising & System Flushing
Well-established annual valve exercising and system flushing programs play an integral part in
maintaining system integrity and reducing water loss. The principal purpose of a valve-exercise
program is to assure that the valve is operable across its full range. System flushing programs
are typically used to maintain water age and quality. Both of these programs can easily
incorporate water loss management elements. Crews equipped with hydrophones or geophones
can use the opportunity to listen to the system at the valve locations and can view the valve
surrounding area for evidence of potential leaking. The valve exercising leaves a valve in a
confirmed position (either fully open or fully closed). Virtually all field leak detection
techniques require that the configuration of the system be known so that flows can be isolated
from the portion of the system being investigated. It is common for a detection crew to believe
that a valve is open (or closed) when in reality it was left in an unexpected position by others.
Similarly, main flushing programs take crews to a large number of hydrants/blow-offs in the
system. A crew equipped and trained to listen can often detect water running at these common
system leak points.
Review 4-44
-------
4.2.9.8 Effective Operations and Active Pressure Management
The final element in a comprehensive water loss management program is an informed operations
plan. The way that a distribution system is operated can play an effective role in reducing water
loss from the system and should be given consideration when establishing a leak management
program.
4.2.9.9 System Modeling
A tool growing in popularity for planning, design and operating support is the distribution
system hydraulic model. PC-based hydraulic models are now affordable for even modest-sized
water operations. The standard hydraulic model provides the user with an easily configurable
way to understand a system's operating parameters (flow rates, pressures, water quality, age,
etc.). But the heart of any hydraulic model is its calibration against field reality. Once
calibrated, the model can provide the water professional a standard for how the system "should"
operate. If during annual maintenance activities the system performs differently from the
model's projections, a major water loss or growing minor leaking may be one culprit. Likewise,
annual maintenance activities afford a perfect opportunity to recalibrate the model as needed
Integrating model routine calibration and output analysis with maintenance activities provides a
potent tool for identifying and potentially even locating system losses.
4.2.9.10 Meter Assessment, Testing and Replacement Programs
Meters are key components to obtaining funds required to operate and maintain a PWS, and
therefore, maintaining a meter assessment, testing and replacement program that optimizes
revenue and aids in locating losses should be a priority of any operation and maintenance
program. Section 3.5 discusses all of the aspects that should go into any metering program.
4.3 EVALUATION
After each water audit, the PWS manager should evaluate the data to determine where
improvements can be made or where further information is required. Data gaps in the
information the PWS has regarding its components and the component maintenance status
should be reviewed and updated as information becomes available. After each intervention the
water system manager should evaluate how successful the actions were. This may be
immediately apparent, such as locating and repairing a leak, or may take significant analysis,
such as evaluating whether a meter replacement program is improving customer metering results.
If the goals of an action were not met, the water system manager should seek to determine why
not and remedy the cause if possible.
Review 4.45
-------
The evaluation process reviews the results of the previous audit and the performance indicators
for potential areas of improvements and signs of impending problems. Because water systems
require maintenance and are always subject to deterioration, the entire process must be repeated
periodically as indicated in Figure 1-2.
4.4 SUMMARY - ASSEMBLING A COMPLETE LOSS CONTROL PROGRAM
It can be overwhelming to consider all of the pieces that go into a water loss and control program
if you do not already have one, although many of the pieces may already exist in your system.
The following sections list the activities and components water utility managers need to consider
to meet the specific demands for their systems.
4.4.1 PUTTING THE PIECES TOGETHER
Consider how your utility is going to implement the following aspects of a loss control policy
answering: Who? What? When? Where? Why? How often? and How much? for each aspect.
Record Keeping
Audit/Balance PI and Benchmark analysis
Economic analysis
Metering -locating, sizing, initial installation, validation, replacement
Meter reading or AMR
Additional system monitoring including SCADA
Data transfer -billing-data error analysis
Real Loss Active Leak Detection Program
o Periodic leak detection sweeps
o DMA, zone flow analysis and other leak testing
o Leak locating - method and training
o Leak repair
o Repair, rehabilitate, or replace analysis
o Repair, rehabilitate, or replace design
o Repair, rehabilitate, or replace execution
Many of the items mentioned above were only briefly described in this guidance. Larger
facilities will be able to manage most of this work in house. Medium and smaller facilities will
likely need help.
Review 4-46
-------
4.4.2 FINDING HELP
Many agencies, associations, and consortia are able to provide advice. Neighboring water
systems with established programs are often willing to help smaller water systems' managers.
State and Federal regulatory agencies often have programs and experts available to provide
assistance. The Association of State Drinking Water Administrators (ASDWA) provides links to
state drinking water and primacy agency home Web pages from their Web site at
http://www.asdwa.org and the EPA Office of Ground Water and Drinking Water provides a Web
site to assist the public and PWS operators at http://www.epa.gov/safewater/index.html. From
this site, state drinking water information and state contacts can be also be found. The Alliance
for Water Efficiency, an organization dedicated to the efficient and sustainable use of water is
also a source of information and resources http://www.allianceforwaterefficiency.org. The
Alliance serves as a North American advocate for water efficient products and programs, and
provides information and assistance on water conservation efforts.
Review 4-47
-------
Appendix A
Summary of Selected State Water Loss Policies
-------
Appendix A - Summary of Selected State Water Loss Policies
The following information is excerpted and summarized from
Summary of State Agency Water Loss Reporting Practices by
Janice A Beecher. (2002) The full report my be found at:
http://www.awwa.org/ResourcesAVaterwiser.cfm
Janice Beecher's Survey of State Agency Water Loss Reporting Practices Final Report to The
American Water Works Association (2002) is the most recent and complete comparison of water
loss policy by state. In this white paper, a case is argued for acceptance of water loss control
standards, including reliable accounting, followed by results of a survey which describes the
state of water accounting and related public state and regional policy.
Surveys were conducted with organizations and state agencies with water policy influence. A
total of 37 surveys were completed, 34 from states, the rest from multi-state agencies. Policy for
11 other states was found through internet searches. This resulted in information on 46
jurisdictions, of which 43 were states. Ten issues were covered by the survey, including:
water-loss policy,
water-loss definitions,
methods for accounting and reporting,
setting standards and benchmarks,
setting goals and targets, planning requirements,
data compilation and publication,
offers of technical assistance,
giving performance incentives, and
requiring or advising audits and enforcement if applicable.
Broadly defined, some sort of water loss policy was found in 36 jurisdictions.
A definition of water loss was given by 17 jurisdictions. It was most commonly expressed as the
remaining percentage of water not recorded as billed versus water pumped into the system.
It was found that 20 state agencies and two water management districts require or provide
guidelines for water accounting and/or water loss reporting.
A-l
-------
None of the jurisdictions covered were found to impose sanctions on systems failing to meet any
of the requirements. Table A-l shows the summary of the finding for the 2002 survey. The
other category in the table below represents the following agencies DRBC = Delaware River
Basin Commission, SJRWMD = St. Johns River Water Management District, SWFWMD =
Southwest Florida Water Management District.
Table A-l Summary Polky Findings
Issue
Has some sort of
Water-loss
Policy
Statement
Has Formal
Definition of
Water Loss
Accounting and
Reporting
Has Standards
and Benchmarks
Sets Goals and
Targets
Has Planning
Requirements
Compilation and
Publication by
Jurisdiction
Provides
Technical
Assistance
Offers
Performance
Incentives
Performs
Auditing and
Enforcement
Jurisdictions
AZ, CA, CT, FL, GA, HI, IN, IA, KS, KY, LA
MD, MA, MN, MD, NV, NH, NY, NC, OH, OR,
PA, RI, SC, TN, TX, UT, VT, VA, WA WV,
WI, WY, DRBC, SWFWMD, SJRWMD
AZ, CA, GA, HI, KS, MD, MA, MN, MO,
OR, PA, RI, SC, TX, WI, DRBC, JRWMD
AZ, CA, GA, HI, IA, KS, KY, MD, MA, MN,
MO, NY, OH, OR, PA, RI, TX, WV, WI,
WY, SWFWMD, SJRWMD
AZ, CA, GA, HI, IN, KS, KY, LA, MD, MA,
MN, MO, NC, OH, OR, PA, RI, SC, TX, UT,
WA, WV, WI, DRBC, SWFWMD, SJRWMD
AZ, CA, FL, GA, HI, KS, KY, ME, MD, MN,
MO, NM, OH, OR, PA, RI, TX, WI,
SWFWMD, SJRWMD
AZ, CA, CT, FL, GA, HI, IA KS, MD, MA,
MN, MO, NV, NH, OR, PA, RI, SC, TX, VT,
VA, WA, WV, WI, SWFWMD, SJRWMD,
DRBC
AZ, CA, HI, KS, KY, MN, PA, RI, WI,
SWFWMD
AK, CA, FL, GA, HI, KS, KY, ME, NV, ND,
OR, PA, RI, SC, TN, TX, VT, WI, SWFWMD
CA, GA, HI, IN, IA, LA, MN, NC, RI, TX, VT,
SJRWMD
AZ, GA, HI, KS, MD, MN, NH, OH, OR, PA,
SC, TX, WI, SWFWMD, SJRWMD
States
(n = 43)
33
15
20
23
18
24
9
18
11
13
Other
(n=3)
o
3
2
2
o
3
2
o
J
1
1
1
2
Total
(n = 46)
6
17
22
26
20
27
10
19
12
15
A-2
-------
Table A-2 shows unaccounted for water standard for selected states
Table A-2 Selected State Standards for Unaccounted-for Water
State
Arizona
California
Florida
Florida
Georgia
Indiana
Kansas
Kentucky
Louisiana
Massachusetts
Minnesota
Missouri
North Carolina
Ohio
Oregon
Pennsylvania
Pennsylvania
Rhode Island
South Carolina
South Carolina
Texas
Texas
Washington
West Virginia
Wisconsin
Delaware River Basin
Commission
Agency
Department of Water Resources
Urban Water Conservation Council
Southwest Florida Water Management District
St. Johns River Water Management District
Environmental Protection Division
Department of Environmental Management
Kansas Water Office
Department of Energy,
Water and Sewer Branch
Department of Environmental Quality
Department of Environmental Protection
Department of Natural Resources
Department of Natural Resources
Division of Water Resources
Public Utility Commission and Environmental
Protection Agency
Water Resources Division
Public Utility Commission
Bureau of Water and Wastewater Management
Water Resources Board
Public Service Commission
Department of Health and
Environmental Control
Water Development Board
Natural Resources Conservation Commission
Department of Health
Public Service Commission
Public Service Commission
Delaware River Basin Commission
Standard
10% (large)
15% (small)
10%
12%or less
10%
Less than 10%
10 to 20%
15%
15%
15%
15%
10%
10%
15%
15%
10-15%
20%
10-15%
10-15%
7.5%
10%
10 to 15%
20%
20%
(10% proposed)
15%
15% (large)
25% (small)
15%
A-2
-------
Appendix B
Miscellaneous Data
-------
Appendix B - Miscellaneous Data
Table B-l Estimated per/Capita/Day Water Use by State
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Dist. Of Columbia
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Abb rev.
AL
AK
AZ
AR
CA
CO
CT
DE
DC
FL
GA
HI
ID
IL
IN
IA
KS
KY
LA
ME
MD
MA
MI
MN
MS
MO
MT
Gal/
Day/
Capita
100
79
150
106
147
145
70
78
179
111
115
119
186
90
76
66
86
70
124
58
105
66
77
148
123
86
129
State
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Puerto Rico
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Virgin Islands
Abbrev.
NE
NV
NH
NJ
NM
NY
NC
ND
OH
OK
OR
PA
PR
RI
SC
SD
TN
TX
UT
VT
VA
WA
WV
WI
WY
VI
United States Avg.
Gal/
Day/
Capita
115
213
71
75
135
119
67
86
50
85
111
62
67
76
81
85
143
218
80
75
138
74
52
163
48
23
105
Source: Soley et al. Water Distribution System Handbook, Larry W Mays. 2000 Pub. McGraw-Hill
B-l
-------
Table B-2 Snapshot of high water loss within distribution systems
Name
Philadelphia
Water
Department
Cleveland
Division of
Water
Memphis Light,
Gas & Water
Cincinnati
Water Works
Jefferson Parish
Water
Department
Portland Water
District
Ann Arbor
Utilities
Department
Duluth/ Public
Works &
Utilities/ Water
North Perm
Water Authority
Waterloo Water
Works
Lorain Utilities
Department
Madison
County Water
Department
Elmira Water
Board
Lebanon
Authority
Selmer Utility
Division
Renton
Williamsport
Municipal
Water Authority
Albany
Eastpointe
Water and
Sewer
Lake County
East Utilities
Paradise
Irrigation
District
State
PA
OH
TN
OH
LA
ME
MI
MN
PA
IA
OH
AL
NY
PA
TN
WA
PA
OR
MI
OH
CA
Volume
Input
(MG/Year)
97,637
94,000
54,798
47,047
25,098
9,293
6,222
8,774
3,311
5,212
4,250
2,326
2,509
2,371
800
2,666
2,610
3,163
1,386
1,394
2,801
Water
Losses
(MG/Year)
30,448
27,000
8,330
8,303
6,055
1,678
1,604
1,424
538
812
850
623
634
500
200
498
917
788
359
219
464
Loss
Percentage
31.18%
28.72%
15.20%
17.65%
24.12%
18.06%
25.78%
16.23%
16.25%
15.58%
20.00%
26.77%
25.27%
21.08%
25.00%
18.66%
35.13%
24.91%
25.88%
15.72%
16.57%
Population
Served
1,670,000
1,500,000
908,222
900,000
425,108
190,000
163,500
99,600
80,000
75,000
74,000
67,200
65,000
57,000
55,000
51,140
51,000
41,000
34,077
26,650
26,000
Per Capita
Loss in
Gallons/Year
58,465
62,667
60,335
52,274
59,039
48,911
38,055
88,092
41,388
69,493
57,432
34,613
38,600
41,596
14,545
52,131
51,176
77,146
40,673
52,308
107,731
Value of Losses
(2008 Yr USD)
$32,272,301
$28,617,713
$8,829,094
$8,800,477
$6,417,787
$1,778,538
$1,700,104
$1,509,319
$570,234
$860,651
$900,928
$660,327
$671,986
$529,958
$211,983
$527,838
$971,942
$835,213
$380,510
$232,121
$491,801
B-2
-------
Table B-2 Snapshot of high water loss within distribution systems
Name
Cordele
Shoshone
Municipal
Pipeline
Piqua Municipal
Water System
Fredericksburg
Clearfield
Municipal
Authority
Bellingham
DPW
Miami Utility
Dept.
Glens Falls
Water
Department
City of
Converse-Public
Works
Spencer
Municipal
Utilities
Anson County
Water System
Berea College
Utilities
Crossett Water
Commission
Warren County
Utility District
State
GA
WY
OH
VA
PA
MA
OK
NY
TX
IA
NC
KY
AR
TN
Volume
Input
(MG/Year)
4,911
4,911
721
1,460
487
598
788
1,364
501
585
2,467
851
512
600
Water
Losses
(MG/Year)
746
746
152
365
115
140
210
334
150
93
614
154
85
100
Loss
Percentage
15.19%
15.19%
21.10%
25.00%
23.61%
23.43%
26.61%
24.48%
29.85%
15.90%
24.87%
18.10%
16.52%
16.67%
Population
Served
21,600
21,600
20,500
20,000
17,000
15,000
14,500
13,000
11,508
11,500
11,200
11,000
9,000
7,200
Per Capita
Loss in
Gallons /Year
227,361
227,361
35,171
73,000
28,647
39,867
54,345
104,923
43,535
50,870
220,268
77,364
56,889
83,333
Value of Losses
(2008 Yr USD)
$790,697
$790,697
$161,107
$386,869
$121,890
$148,388
$222,582
$354,012
$158,987
$98,572
$650,788
$163,227
$90,093
$105,992
Source: AWWA, 2003
* Greater than 15% total water loss, of which more than 50% was real loss.
-------
Appendix C
Water Audit Worksheet Examples
-------
Appendix C - Water Audit Worksheet Example
From:
Texas Water Development Board - Water Audit Worksheets
TWDB (Texas Water Development Board) and Mark Mathis. 2005. Water Loss Manual. Austin, Texas:
Texas Water Development Board.
http://www.twdb.state.tx.us/assistance/conservation/MunicipalAVater Audit/Leak DetectionAVaterLoss
Manual 2005.pdf
C-l
-------
WATER AUDIT WORKSHEET
Utility Name:
Type of Utility: (circle one) WSC MUD WCID SUD CITY Other
Regional Water Planning Group(s) in which this system operates:
http://www.twdb.state.tx.us/mapping/maps/pdf/sb 1 groups 8x11 .pdf
Name of person completing this form:
Phone number of person completing form (with area code)
Mailing address of utility:
Reporting Period: From To
Percentage of water used: Surface Groundwater_
Mean household income of population served:
http://factfinder.census.gov/servlet/SAFFPeople?
Population served:
Note: unit of measure (acre-foot or million gallons) must stay consistent throughout report
1. SYSTEM INPUT VOLUME MG ACRE-FT OTHER
System Input Volume - Amount of water put into delivery system:
Master Meter Adjustment - Volume master meter did not account for: +/-
Corrected Input Volume - Water delivery plus/minus Master Meter Adjustment:
2. AUTHORIZED CONSUMPTION
Revenue Water
Billed Metered - All water sold:
Billed Unmetered - All water sold but not metered:
Non-Revenue Water
Unbilled metered - City and local government use, metered line flushing:
Unbilled unmetered - Line flushing/fire dept use: (estimate)
Authorized Consumption - The total of all Authorized water:
C-2
-------
3. WATER LOSS
Apparent Loss
Customer Meter Under-Registering - Inaccurate customer meters +/-
Billing Adjustment/Waivers
Unauthorized consumption (theft or estimate)
Total of Apparent Loss
Real Loss
Storage tank overflows (estimate)
Main break/leaks: (estimate)
Customer service line leaks/breaks: (estimate)
Total of Real Loss
Total Water Loss = Apparent Loss + Real Loss
4. TECHNICAL PERFORMANCE INDICATORS
Performance Indicators for Real Loss
Number of service connections
Number of miles of main lines
Service connections divided by miles of main
Total Real Loss/Miles of Main/365
Total Real Loss/No, of Service Connections/365
5. FINANCIAL PERFORMANCE INDICATORS
Total Real Loss
Production cost of water
Total Real Loss multiplied by production cost of water:
(Example from instruction sheet) Real Loss x $2.50/1000
Total Apparent Loss
Retail cost of water
Total Apparent Loss multiplied by retail cost of water:
(Example from instruction sheet) Apparent Loss x $4.25/1000
C-3
-------
WATER AUDIT WORKSHEET INSTRUCTIONS
This instruction guide is designed to aid in completing the Water Audit Reporting Form and
submitting the most accurate data available. This information will aid in determining which
operational areas may need assistance. A few general notes on the first section:
List the Regional Water Planning Group in which the utility is located. This information
may be determined by using the Web site listed on the reporting form.
Remember that the type(s) of source water used must total 100%.
Use the Web address on the reporting form to locate the mean income of population
served. The data may be obtained by metropolitan area, county, and/or zip code.
Estimate the population the utility serves (this is not the number of service connections).
Note the reporting period. Either a calendar or fiscal year may be used.
Use consistent units in reporting the data, either million gallons or acre-feet.
1. System Input Volume
a. Water Delivery - Includes all water pumped, produced, or obtained through
interconnects and purchased water. This is the sum of all master or source meters
for the year.
Example:
Water Delivery is 8,983,674 gallons
b. Master Meter Accuracy - Is achieved by calibrating the master or source meters
to determine the accuracy level expressed as a percentage.
Example:
Water Meter Accuracy is 96%.
c. Corrected Input Volume- Is obtained by dividing the Water Delivery by Water
Meter Accuracy and multiplying by 100.
Example:
8,983,674-.96 = 9,357,993
d. Master meter adjustment - Is obtained by subtracting Water Delivery from the
Corrected input volume.
Example:
9,357,993 - 8,983,674 = 374,319
Note: If meters are over registering, divide Water Delivery by 1.03, if the meters
are 103 percent accurate and subtract the adjustment due to the over registering
of the meter. The master meters have registered more water than the actual
pumped amount.
C-4
-------
2. Authorized Consumption
a. Billed Metered - All water sold that has been metered.
b. Billed Unmetered - All water sold but not metered; can be an estimate.
c. Unbilled Metered - Unbilled water but is metered. Enter all metered flushing here.
d. Unbilled Unmetered - Unbilled water that is not metered. Enter all unmetered
flushing here.
Note: Authorized Water Usage may be subtracted from the Corrected Input Volume to obtain
Total Water Loss for the year.
Corrected Input Volume - Authorized Water Usage = Total Water Loss
3. Water Loss
A. Apparent Loss
a. Customer Meter Under Registering -If customer meters are 98% accurate, that
means the meters are 2% under registering. Simply divide the Total Water Sold
by accuracy level of meters.
Example:
Total Water Sold that has been metered = 7,125,000 million gallons
7,125,000 -H .98 = 7,270,408 gallons
7,270,408 - 7,125,000 = 145,408 gallons not recorded by meter.
Note: If meters are over registering by 4 % then divide Water Delivery by 1.04 and
then subtract that amount.
b. Billing Adjustments/Waivers - Amount of water that was waived during the audit
year.
Example:
If the utility waived 28,000 gallons due to leaks on the customer's side
during the year, 28,000 would be entered.
c. Unauthorized Consumption - Estimate amount of water lost due to theft.
Example: If a customer moved into a new home and began to use water without
authorization.
B. Real Loss
a. Tank Overflows - Amount of water lost due to storage overflows.
b. Main Leaks/Breaks - Amount of water lost through main leaks and breaks.
c. Customer Service line Leaks - Amount of water lost through service line leaks.
Real Loss estimates should be as accurate as possible.
Note: The sum of Total Water Loss and Authorized Consumption equals
Corrected Input Volume.
C-5
-------
4. Technical Performance Indicators
Performance Indicators are quantitative measures of key aspects within the utility. With
the use of these indicators, each utility will have a history to track performance.
The first formula is Total Real Loss/Miles of Main/Day:
1. Use the Total Real Loss number from the reporting form, then divide by
2. Miles of Main lines, then divide by
3. 365 (days in a year)
4. Record this number where indicated.
The second formula is Total Real Loss/No, of Service Connections/Day:
1. Use the Total Real Loss number from the reporting form, divide by
2. Number of Service connections, divide by
3. 365 (days in a year)
4. Record this number where indicated.
5. Financial Performance Indicators
1. Value of Current Real Loss
Example
Total of Real Loss = 1,625,394 gallons
$2.50/1000 = production cost
1,625,394 x $2.50/1000= $4,063.50
$4,063.50 (Value of Real Loss /year)
2. Value of Current Apparent Loss
Example
Total of Current Loss = 189,408 gallons
$4.25/1000 = retail rate
189,408 x 4.25/1000= $805.00
$805.00 (Value of Current Apparent Loss/year)
C-6
-------
Appendix D
CUPSS Example
-------
Appendix D
Check Up Program for Small Systems (CUPSS)
Credits, debits, new equipment, old equipment, repairs, upgrades...it is a lot to keep straight. The
U.S. Environmental Protection Agency (EPA) has created a tool to help water systems keep all
aspects of asset management straight: the Check Up Program for Small Systems (CUPSS).
CUPSS is a free software package that has a downloadable, detailed user manual to help water
and wastewater systems use the software to best help them.
What is CUPSS?
CUPSS is a simple, easy to use asset management program that helps small utilities manage and
finance existing and future drinking water and wastewater infrastructure. CUPSS is stand-alone,
user-friendly software with an attractive interface and tutorial, delivered on CD. The end-user for
CUPSS is a small public water system or wastewater facility serving less than 3,300 customers
or medium-sized systems new to asset management. The program offers personalized, intuitive
navigation, including areas like "My Check Up Reports" and "My CUPSS Plan."
Why use CUPSS?
CUPSS can assist in water loss management. Operation and maintenance schedules can be
entered, including daily, weekly, monthly and yearly tasks. A user could set-up tasks to monitor
loss and the regular maintenance of assets. The software allows for the task to be assigned to
specified day(s) and time(s). It also helps create a schematic of a system and an inventory of its
equipment. Small icons can be linked to show pumps, distribution lines, chemical systems, wells,
and other parts of a system and how they work together.
The schematic can be created along with an inventory list. CUPSS serves as an asset inventory
database. When creating the inventory, the software asks for the condition and age of each item.
The cost, maintenance schedule and supplier and/or manufacturer can be added for each
inventory item. Also, a notes field is available to add any additional information a user wants to
note for the asset.
CUPSS provides Check Up and CUPSS Plan reports. The Asset Check Up report tool provides a
report of assets entered and their risks. The Financial Check Up Report tool projects a 10 year
financial status. My CUPSS Plan tool creates a customized asset management plan. This
comprehensive feature draws information entered throughout CUPSS and formats the
information into a user-friendly report.
Where do I find CUPSS?
Basic information about CUPSS, software download and training materials may be found at
epa.gov/cupss.
D-l
-------
Selected Screen Captures from the CUPSS Software Program
Check Up Program for Small Systems (CUPSS)
ciirS Check Up Program for Small Systems
Set-up ' Switch ""'^ i Create Us*r ' He|p ' Trainina i
Inventory
My
Finances
My
Check Up
CUPSS Plan
Beauty View Acres Subdivision - DW 1
Print Blank Worksheet
The asset inventory form allows you to enter information about your assets. This information will then 0
be used in several of the CUPSS reports and to generate your prioritized asset list.
(*) Indicates required fields
Basic Inform;
* Asset Name
* Location
* Asset
Category
ID
Latitude
Notes
ition
Select Category
0
0
Select Associated Asset ,v 0
Select Associated Location v 0
' 0 *Asset Type Select Asset Type v
0
0
Size 0
Longitude ฃ)
0
[add]
0
Status and Cc
* Condition
* Redundancy
* Asset Status
Select Asset
mdition - Required to Calculate Priority
Select Condition Rating
Select Redundancy
Select Status
v
Select Asset Being Replacei v
0 * CoF select CoF Rating
^^ Can this asset be repaired? Qi Yes (*j
0 Can this asset be rehabilitated? O Yes ฉ
Show asset in the schematic? >Q> Yes (*)
e
No 0
No 0
No
[Asset Risk MatriK
r
I '""' "
i-
: :
K'fcd in R ik
Inventoried Asset
List
- Source
Well#l
pump
well property
Wellhouse Tampa
0 Pumping Facility
Main value
Security
Chlorinator
Well House
ED Treatment
Chlorine testing
bl Storage
Storage Tank
Figure D-l. Asset Inventory window. The Asset Inventory window has 4 parts: (1) Basic Information, (2) Status and
Condition, (3) Cost and Maintenance and (4)Manufacturer and Supplier. This figure shows the first 2 parts.
Draft Final
D-2
-------
Status and Condition - Required to Calculate Priority
* Condition 5e|ect condition Rating
fRedundancy
*&
SetectCoFRa&ig
Asset Status
Select Asset
Select Redundancy
Select Status
ieieci HJSCI _ , . . . n . r ,
. . Select Asset Being Replacei v
Can this asset be repaired? Q Yes ฎ No
Can this asset be rehabilitated? Yes-0 No
Show asset in the schematic? " Yes /' No
Cost and Maintenance
* Installation Date
Expected Useful
Life
Original Cost
* Replacement Cost
Routine
Maintenance Cost
Select Freque v
Maintained According to Factory Recommendation 0
Create a task
Manufacturer and Supplier - Optional
Model Number
Supplier Select Existing Supplier v
Address
City, State, Zip
Phillip. FJH
0 Manufacturer j5etert Existing Hanufactiv
Select state
wennouse lampa
- Pumping Facility
Main valve
Security
Chlorinator
Well House
3 Treatment
Chlorine testing
- Storage
Storage Tank
- Distribution
Water Production Meter
Tank
Distribution
Figure D-2. Asset Inventory window continued. The Asset Inventory window has 4 parts: (1) Basic Information, (2) Status
and Condition, (3) Cost and Maintenance and (4)Manufacturer and Supplier. This figure shows the 3 of the 4 parts.
Draft Final
D-3
-------
Check Up Program for Small Systems (CUPSS)
****** Check Up Program for Small Systems
Set-up | Switch Utility | Create User | Help | Training | Exit
My
Inventory
My
Finances
My
Check Up
CUPSS Plan
Beauty View Acres Subdivision - DW Inventory J
The following is a list of assets currently in your inventory. To sort the table click on the column headings. To edit the information, right click on the selected
record and click "edit row". ^^
II Priority || Asset: || Category ] AssetType || Condition
1 Welltfl Source Wells and Springs Poor
2 pump Source Pumping Equip... Good
3 Main valve Pumping Facility Pumping Equip... Fair (Average)
4 Security Pumping Facility Security Equipm... Good
5 Tank Distribution Distribution / C... Good
6 Chlorinator Pumping Facility Disinfection Equ... Fair (Average)
7 Distribution Distribution Distribution / C... Good
8 Water Producti... Distribution Distribution / C... Fair (Average)
9 Chlorine testing Treatment Lab / Monitorin... Excellent
10 well property Source Land Excellent
11 Storage Tank Storage Concrete & Met... Good
12 Well House Pumping Facility Pumping Equip... Good
Not Available Wellhouse Tampa Source Wellhouse None
.. ป! -i-n f-
| CoP Keounaanty 1 Kepl-acement: Uate
Catastrophic 0% 2009-02-01
Catastrophic 0% 2011-02-01
Major 0% 2011-02-01
Minor 0%. 2009-02-01
Catastrophic 0% 2036-02-01
Insignificant 0% 2008-02-01
Major 0% 2038-02-01
Minor 0% 2035-02-01
Insignificant 100% 2008-02-01
Insignificant 0% 2308-02-01
Moderate 0% 2055-02-01
Major 0% 2019-02-01
None None None
HSB
Figure D-3. My Inventory List. On this page, you can see a list of all saved assets. Each asset is given a priority based on the
information entered in the Asset Inventory form.
Draft Final
D-4
-------
Appendix E
Case Studies of Implemented Water Loss Programs
-------
Appendix E - Case Studies of Implemented Water Loss Programs
(EPA is currently searching for case studies of smaller water systems that have implemented a
water loss prevention program.)
E-l
-------
References
-------
References
Achim, D., F. Ghotb, KJ. McManus. 2007. Prediction of water pipe asset life using neural
networks. J. Infrastruct. Syst. Vol. 13(1):26-30.
http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JITSE4000013000001000
026000001&idtvpe=cvips&gifs=ves (accessed 3-Sep-08).
Adixen-USA. Liquid and gas transportation; Commissioning and maintenance. Alcatel Vacuum
Technology.
http://www.adixen-usa.com/all/dyn/markets/application.php?pid=94&div=2&lg=us (accessed 2-
Sep-08).
American Society of Civil Engineers (ASCE). 2005 Report Card on America's Infrastructure.
http://www.asce.org/files/pdf/reportcard/2005 Report Card-Full Report.pdf (accessed 2-Sep-
08)
Andersen, Bj0rn, and Per-Gaute Pettersen. 1996. The benchmarking handbook: Step-by-step
instructions. New York, NY: Springer.
Arscott, A. International Water Association, Water Loss Conference 2007.
http://www.waterloss2007.com/pdfjyortraege/Mittwoch/C9-3.pdf (accessed Sep-08)
ASI (Acoustic Systems Incorporated). Leak detection system overview. Houston, Texas: ASI.
http://www.wavealert.com/Pages/sysl.html (accessed 3-Sep-08).
AWWA (American Water Works Association). 1999. Water audits and leak detection, 2nd Ed.
(Manual of Water Supply Practice M-36). Christensen, Melissa, and Michael Malgrande, eds.
Denver, CO: American Water Works Association.
AWWA (American Water Works Association). 2003. WATERASTATS, 2002 water utility
distribution database. Denver, CO: AWWA.
AWWA (American Water Works Association). 2008. Free water audit software. Denver, CO:
AWWA.
http://www.awwa.org/Resources/Content.cfm?ItemNumber=590 (accessed 3-Sep-08).
AWWA (American Water Works Association). 2008. Water loss control. Denver, CO:
AWWA.
http://www.awwa.org/Resources/topicspecific.cfm?ItemNumber=3653&navItemNumber=3297
(accessed 3-Sep-08).
AWWA (American Water Works Association). More water for your dollar-arriving at an
economic level of water loss. Denver, CO: AWWA.
http://www.awwa.org/files/resources/waterwi ser/references/pdfs/GENERAL_WATER_LOSS_
MWH Arriving at an Economic Level of Water Loss.pdf (accessed 3-Sep-08).
AwwaRF (American Water Works Association Research Foundation). 2008. AwwaRF featured
topics - Key findings. Denver, Colorado: AwwaRF.
R-l
-------
http://www.awwarf.Org/research/T opicsAndProjects/keyFindings.aspx?id=99 (accessed 2-Sep-
08).
Baltzley, Steve. Water meter testing. Avanticompany.com. Avon Park, FL: Avanti Company.
http://www.avanticompany.com/articles/metertesting.html (accessed 3-Sep-08).
Beecher, Janice A. 2002. Survey of state agency water loss reporting practices. Indianapolis,
IN: Beecher Policy Research, Inc.
http://www.cuwcc.org/Uploads/committee/AWWAWaterLossPolicySurvey.pdf (Accessed 29-
Aug-08).
Besner, M.-C., V. Gauthier, P. Servais, and A. Camper. 2002. Explaining the occurrence of
coliforms in distribution systems. Jour. AWWA 94(8):95-109.
Bonds, Richard W., P.E. 1997. Stray current effects on ductile iron pipe. Birmingham, AL:
Ductile Iron Pipe Research Association.
Boorman, G. A. V. Dellarco, J. K. Dunnick, R. E. Chapin, Sid. Hunter, F. Hauchman, H.
Gardner, M. Cox, and R. C. Sills. 1999. Drinking Water Disinfection Byproducts: Review and
Approach to Toxicity Evaluation. Environmental Health Perspectives, Vol. 107, Supplement
February 1999. pp 207-217.
http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1566350&blobtype=pdf
Bourg, Joseph. 2008. Water conservation. WBDG (Whole Building Design Guide), National
Institute of Building Sciences.
http://www.wbdg.org/resources/water conservation.php (accessed 3-Sep-08).
Brady, Jr., Robert F. 1995. Fact sheet from the Navy pollution prevention conference on the
restoration of drinking water piping with nontoxic epoxy linings. 1995 Navy Pollution
Prevention Conference, Arlington, VA, June 6, 1995.
http://www.p2pays.org/ref/ll/10365.htm (accessed 3-Sep-08).
Brothers, Ken. 2003. A practical approach to water loss reduction. IWA Water Loss Task
Force. London, UK: IWA Publishing.
http://www.iwapublishing.com/pdf/WaterLoss-Jun.pdf (accessed 3-Sep-08).
Burstall, Tim. 1997. Bulk water pipelines. London, UK: Thomas Telford.
Business Wire. 2005. American water announces pilot program in water loss management;
Connellsville, PA pilot uses AMR technology to detect and repair leaks. Findarticles.com, July
15,2005.
http://fmdarticles.eom/p/articles/mi mOEIN/is 2005 July 15/ai nl4790673/pg 1 (accessed 3-
Sep-08).
Buyer's Inspection Service. Polybutylene piping. Dayton, OH: Buyer's Inspection Service.
http://www.greatinspector.com/faq-plum-poly.html (accessed 2-Sep-08).
R-2
-------
Camper, A. K., K. Brastrup, A. Sandvig, J. Clement, C. Spencer, and A. J. Capuzzi. 2003.
Effect of distribution system materials on bacterial regrowth. Jour.AWWA 95(7): 107-121.
Centers for Disease Control and Prevention, Division of Oral Health, (CDC) August 16, 2007.
Fluoridation of Drinking Water and Corrosion of Pipes in Distribution Systems, Fact Sheets,
http://www.cdc.gov/Fluoridation/fact_sheets/engineering/corrosion.htm (accessed 2-Sep-08).
Chase, Bruce W., and Laura B. Triggs. 2001. How to implement GASB Statement No. 34.
Journal of Accountancy Online 192(5), November, 2001.
http://aicpa.org/pubs/jofa/nov2001/chase.htm 3-Sep-08 (accessed 3-Sep-08).
Chemical Injection Technologies, Inc. 2007. WG-602 Water Quality Analyzer. Fort Pierce,
FL: Chemical Injection Technologies, Inc.
http://www.chlorinators.com/PDFs/Brochures/WG-602SellSheet.pdf (accessed 2-Sep-08).
City of Minneapolis, Public Works. Water meter questions. City of Minneapolis, Minnesota.
http://www.ci.minneapolis.mn.us/utility-billing/watermeter.asp (accessed 2-Sep-08).
Committee on Public Water Supply Distribution Systems: Assessing and Reducing Risks. 2006.
Drinking water distribution systems: assessing and reducing risks. Washington, DC: The
National Academies Press, http://www.nap.edu/catalog.php7record_id=l 1728
Corbitt, Robert A. 1990. Standard handbook of environmental engineering. New York, NY:
McGraw-Hill.
Craun, M. F., Gunther F Craun , Rebecca. Calderon and Michael J. Beach. 2006. Waterborne
Outbreaks reported in the United States, Torn. Of Water and Health 04.Suppl 2, pp 19-30.
http://epa.gov/nheerl/articles/2006/waterborne_disease/waterborne_outbreaks.pdf
Craun, G. F., and R. L. Calderon. 2003. Waterborne disease outbreaks caused by distribution
system deficiencies. Jour. AWWA 93(9):64-75.
Cromwell, J., E. Speranza, and H. Reynolds. 200la Reinvesting in Drinking Water
Infrastructure: Dawn of the Replacement Era. Denver, CO: AWWA.
Cromwell, J., G. Nestel, R. Albani, L. Paralez, A. Deb, and F. Grablutz. 2001b. Financial and
Economic Optimization of Water Main Replacement Programs. Denver, CO: AWWA Research
Foundation.
CUWCC (California Urban Water Conservation Council). 2005. Data and methods for cost-
effectiveness analysis. Sacramento, CA: CUWCC.
http://www.cuwcc.org/uploads/tech_docs/Costs_Savings_Study_Final_042805.pdf (accessed 3-
Sep-08).
CUWCC (California Urban Water Conservation Council). 2007. BPM cost and savings study.
Sacramento, CA: CUWCC.
http://www.cuwcc.org/technical/bmp03/BMP03-Excerpt-Costs-Saving-Study-v6-July-2007.pdf
(accessed 3-Sep-08).
R-3
-------
Deb, A.K., YJ. Hasit, H.M. Schoser, and J.K. Snyder. 2002a. Decision Support System
forDistribution System Piping Renewal. Denver, CO: AWWA Research Foundation:Distribution
Systems.
Deb, A.K., P.M. Grablutz, YJ. Hasit, J.K. Snyder, G.V. Loganathan, andN. Agbenowski.2002b.
Prioritizing Water Main Replacement and Rehabilitation. Denver, CO: AWWAResearch
Foundation.
deMonsabert, S., and B.L. Liner. 1996. WATERGY: A water and energy conservation model
for federal facilities. Paper presented at CONSERV '96, January 6, 1996, in Orlando, Florida.
http://wwwl.eere.energy.gov/femp/pdfs/watergy_manual.pdf (Accessed 29-Aug-08).
Dickinson, Mary Ann. 2008. A vision for advanced water conservation. Alliance for Water
Efficiency.
http://www.texaswatermatters.org/pdfs/Mary Ann_partl.pdf (accessed 2-Sep-08).
Dickinson, Mary Ann. 2008. Developing water conservation strategies. Alliance for Water
Efficiency.
http://www.co.mchenry.il.us/common/countyDpt/WaterRes/PDFDocs/08-05-
13McHenrvCountvmaryanndickinson.pdf (accessed 2-Sep-08).
DIPRA (Ductile Iron Pipe Research Association). 2007. Ductile iron pipe joints
and their uses. Birmingham, Alabama: DIPRA.
http://www.dipra.org/pdf/joints.pdf (accessed 2-Sep-08).
DOH (Washington State Department of Health). 2007. Water use efficiency handbook.
Washington State Department of Health, Division of Environmental Health, Office of Drinking
Water, DOH Pub. #331-375.
http://www.doh.wa.gov/ehp/dw/municipal_water/33 l-375_7-24-07.pdf (accessed 3-Sep-08).
DWR (State of California Department of Water Resources). 2008. Urban drought guidebook.
State of California Department of Water Resources Office of Water Use Efficiency and
Transfers.
http://www.owue.water.ca.gov/docs/UrbanDroughtGuide.pdf (accessed 2-Sep-08).
EBAA Iron Connections, GI-1, 1993. Corrosion & Cathodic Protection in Underground Piping
Systems", http://www.ebaa.com/pdf/pdf/GI-l.pdf (accessed 2-Sep-08).
Elert, G., and his students. 2004. Price of water. In The Physics Factbook, Glenn Elert, ed.
Hypertextbook.com.
http://hvpertextbook.com/facts/2004/JosephSabatelle.shtml (accessed 3-Sep-08).
EOEA (Executive Office of Environmental Affairs) and WRC (Water Resources Commission).
2006. Water Conservation Standards. The Commonwealth of Massachusetts.
http://www.mass.gov/envir/mwrc/pdf/Conservati on_Standards.pdf (Accessed 15-Aug-2008).
R-4
-------
EPD (Georgia Environmental Protection Division). 2007. Water loss control program: EPD
guidance document. Georgia Environmental Protection Division, Watershed Protection Branch.
http://wwwl.gadnr.org/cws/Documents/Water_Loss_Program.pdf (accessed 3-Sep-08).
European Pipeline Center. Clean water service. St Veit an der Glan, Austria: MTA
Messtechnik.
http://www.mta-messtechnik.at/GB/trinkwasser2 GB.html (accessed 3-Sep-08).
Eyuboglu, S., Mahdi, H., and Al-Shukri, H., Dept of Applied Science, University of Arkansas.
Detection of Water Leaks Using Ground Penetrating Radar,
http://www.dot.state.fl.us/statematerialsoffice/geotechnical/conference/materials/eyuboglu-
mahdi-alshukri.pdf (accessed 2-Sep-08)
Fantozzi, M., and A. Lambert. 2007. Including the effects of pressure management in
calculations of short run economic leakage levels. Paper presented at the IWA International
Specialised Conference, Water Loss 2007, September, 2007, in Bucharest.
http://www.leakssuite.com/Documents/Papers/003 Fantozzi.pdf (accessed 29-Aug-08).
Farley, Malcolm. 2003. Understanding and managing losses in water distribution networks.
Water & Wastewater International, September, 2003.
http://ww.pennnet.com/display _article/l 89881/20/ARTCL/none/none/l/Understanding-and-
managing-losses-in-water-distribution-networks/ (accessed 3-Sep-08).
Fleming, K., J. Dugandzic, M. LeChevallier, and R. Gullick. 2006. Susceptibility of potable
water distribution systems to negative pressure transients. The State of New Jersey - Division of
Science, Research and Technology.
http://www.state.nj.us/dep/dsr/dw/susceptibilitv-potablewater.p65.pdf (Accessed 29-Aug-08).
Fleming, Kala. 2007. Susceptibility of PWS to negative pressure transients. Presented at
AWWA Research Committee Seminar, 22-Oct-07.
http://www.vaawwa.org/files_PDFs/2007resrch_fleming.pdf (accessed 3-Sep-08).
Flowmetrix, Inc. Advanced water, gas, and petroleum leak detection digital systems and
pipeline management. Maynard, MA: Flowmetrix, Inc.
http://www.flowmetrix.com/index.htm (accessed 3-Sep-08).
Foundation for Cross-Connection Control and Hydraulic Research. 2002. Backflow
introduction. Viterbi School of Engineering, University of Southern California.
http://www.usc.edu/dept/fccchr/introduction.html (accessed 2-Sep-08).
Geldreich, E.E. 1996. Microbial Quality of Water Supply in Distribution Systems. Boca Raton,
FL: Lewis Publishers.
Griffiths, Jeffrey K. 2008. Alternative secondary disinfectants: Advantages and Disadvantages.
Vermont Water Supply Division, Department of Environmental Conservation. Disinfectant
Byproduct Symposium, November, 2007, Vermont.
www.vermontdrinkingwater.org/DBPsymposium/AlternativeSecondaryDisinfectants.ppt
(accessed 2-Sep-08).
R-5
-------
Grigg, N.S. 2004. Assessment and Renewal of Water Distribution Systems. AwwaRF Report
Number 91025. Denver, CO.
Hammer, Mark J. and Hammer, Mark J., Jr., "Water and Wastewater Technology", 5th edition
(2003), Pearson-Prentice Hall
Harvie, Jamie, and Tom Lent. 2002. PVC-Free pipe purchasers' report. Washington, DC:
Healthy Building Network.
http://www.healthybuilding.net/pvc/pipes_report.html (accessed 2-Sep-08).
Haas, C.N. 1999a. Benefits of Using a Disinfectant Residual. Jour. AWWA 91(l):65-69.
Heneghan & Associates. 2004. Water loss - What is it? Civil Talk, September, 2004.
http://www.haengr.com/Newsletters/newsletter92004.htm (accessed 3-Sep-08).
Hetek Solutions, Inc. 2008. Water lost is water wasted - Working with the Water Loss Task
Force. London, Ontario: Hetek Solutions, Inc.
http://www.hetek.com/index.php?option=com_content&task=view&id=22&Itemid= 141
(accessed 3-Sep-08).
Higgins, M. S., P. O. Paulson. 2006. Fiber Optic Sensors for Acoustic Monitoring of PCCP,
White Paper, Pure Technologies,
http://www.puretechnologiesltd.com/html/technical_papers.php?year=2006#link
Holmes, Matthew. 2005. Accounting for Total Water Use: A Water Loss Optimization
Program. Albuquerque, NM: New Mexico Rural Water Association.
http://nmcollaborations.nmt.edu/PDF%20Files/Accounting%20for%20Total%20Water%20a%20
Water%20Loss%20Optimization%20Program%20Holmes%20Presentation.pdf (accessed 3-Sep-
08).
Hunaidi, Osama. 2000. Detecting leaks in water distribution pipes. National Research Council
Canada , Construction Technology Update No. 40, Oct. 2000.
http://irc.nrc-cnrc.gc.ca/pubs/ctus/40_e.html (accessed 3-Sep-08).
Hutson, S.S., N.L. Barber, J.F. Kenny, K.S. Linsey, D.S. Lumia, and M.A. Maupin. 2004.
Estimated Use of Water in the United States in 2000; US Geological Survey Circular 1268.
Reston, Virginia: US Geological Survey.
http://pubs.usgs.gov/circ/2004/circl268/pdf/circularl268.pdf (Accessed 26-Aug-08).
IDS Water. 2004. Leakage economics: Plugging the knowledge gap. Chicago, IL: IDS
Publishing.
http://www.idswater.com/Common/exhib 64/WWT%20Leakage%20Economics%20Article%20
Feb%202004.doc (accessed 3-Sep-08).
IDS Water. Trenchless pipe rehabilitation replacement, dynamic pipe bursting, pipe eating,
static pipe bursting method, water flush drilling method. International Society for Trenchless
Technology. Industry IDS, Inc.
R-6
-------
http://www.idswater.com/water/us/ISTT/Trenchless_Pipe_Rehabilitati on/10_0/g_supplier_4. htm
L(accessed 2-Sep-08).
IWA Water Loss Task Force. 2007. Leak location and repair guidance notes. London, UK:
IWA.
http://www.fmdmoreleaks.com/downloads/IW A%20LD%20Guidance%20Notes%20260307%2
0_2_.pdf (accessed 3-Sep-08).
IWA Water Loss Task Force. Water loss 2007. IWA Specialist Group, Efficient Operation and
Management and Romanian Water Association. Specialist Conference, Bucharest, Romania, 23-
26 September, 2007. http://www.waterloss2007.com/ (accessed 3-Sep-08).
Jakubowski, Tom. 2006. Best management practices help control water loss. On Tap
Magazine, Spring 2006, pp. 25-27. www.nesc.wvu.edu/pdf/DW/conserve/water_loss_otsp06.pdf
(accessed 3-Sep-08).
Johnson, Randy. 2001. Drinking Water Contaminants. Drinking Water Resources website
(Cyb er-nook. com).
http://www.cyber-nook.com/water/tbl_cont.html (accessed 3-Sep-08).
Jones, G.M (Editor-in-Chief). 2006. Pumping station design, 3rd edition. Burlington, MA:
Butterworth-Heinemann.
Karim, M. R., M. Abbaszadegan, and M. W. LeChevallier. 2003. Potential for Pathogen
Intrusion during Pressure Transients. Jour AWWA 95(5): 134-146.
Kenniwick, City of. 2004. Cross connection control: the key to safe, clean drinking water. City
of Kennewick, WA.
http://www.ci.kennewick.wa.us/Municipal Services/Cross Connection Control.asp (accessed
29-Aug-08).
Kidd, Benjamin. 2005. Disinfectant Residual Reporting. Presented at TCEQ Public Drinking
Water Section, May 4, 2005. Texas Commission on Environmental Quality (TCEQ).
www.tceq.state.tx.us/files/TF2005 DLQOR.pdf 4319992.pdf (accessed 2-Sep-08).
Kingdom, B., R. Liemberger, and P. Marin. 2006. The challenge of reducing non-revenue water
(NRW) in developing countries. Washington, DC: The World Bank.
http://siteresources.worldbank.org/INTWSS/Resources/WSS8fm4.pdf (Accessed 26-Aug-08).
Kirmeyer, G.J., W. Richards, and C.D. Smith. 1994. An assessment of water distribution
systems and associated research needs. Denver, CO: AWWA Research Foundation: Distribution
Systems.
Kiss, G., K. Koncz, and C. Melinte. 2006. WaterPipe project: an innovative high resolution
Ground Penetration Imaging Radar (GPIR) for detecting water pipes and for detecting leaks and
a Decision-Support-System (DSS) for the rehabilitation management of the water pipelines.
Brussels: European Commission.
http://waterloss2007.com/pdf_vortraege/Mittwoch/A8-2.pdf (accessed 2-Sep-08).
R-7
-------
Lahlou, Zacharia M. 2001. Leak detection and water loss control. Tech Brief, a National
Drinking Water Clearinghouse Fact Sheet. The National Drinking Water Clearinghouse,
National Environmental Services Center, West Virginia University.
http://www.nesc.wvu.edu/ndwc/pdf/OT/TB/TB LeakDetection.pdf (accessed 3-Sep-08).
Lambert, Allan. 2003. What do we know about pressure:leakage relationships in distribution
systems? Presented at the IWA Conference 'System approach to leakage control and water
distribution systems management', May, 2000, in Brno, Czech Republic.
Leak-Pro Co. Water leak detection equipment and training with audio generator, leak-pro.com.
Lake Montezuma, AZ: Leak-Pro.
http://www.leak-pro.com/ (accessed 3-Sep-08).
Leakssuite.com. Concepts. Leakssuite Software, ILMSS Ltd.
http://www.leakssuite.com/Documents/Concepts.html (accessed 3-Sep-08).
LeChevallier M.W., R.W. Gullick, M.R. Karim, M. Friedman, I.E. Funk. 2003. The potential
for health risks from intrusion of contaminants into the distribution system from pressure
transients. J Water Health 1(1):3-14.
Levin, Ronnie B., Paul R. Epstein, Tim E. Ford, Winston Harrington, Erik Olson, and Eric G.
Reichard. 2002. US drinking water challenges in the twenty-first century. Environmental
Health Perspectives 110 (Suppl. l)February 2002.
http://www.ehponline.org/members/2002/suppl-l/43-521evin/EHP110slp43PDF.PDF (accessed
3-Sep-08).
Liemberger, R., K. Brothers, A. Lambert, R. McKenzie, A. Rizzo, T. Waldron. Water loss
performance indicators. Presented at the Water Loss 2007 Conference, 23-26 September 2007,
in Bucharest, Romania.
http://waterloss2007.com/pdf vortraege/Montag/B2-l .pdf (accessed 3-Sep-08).
Liemberger, Roland. 2002. Do you know how misleading the use of wrong performance
indicators can be? Paper presented at the IWA Managing Leakage Conference, November,
2002, in Cyprus.
http://www.bws-malavsia.com/common/nrw/download/papercyprusl.pdf (accessed 29-Aug-08).
Liemberger, Roland. 2006. Introduction to water loss analysis and reduction. Presentation at
the IWA World Water Congress and Exhibition, September, 2006, in Beijing, China.
http://www.liemberger.cc/diverse_uploads/Water%20Loss%20workshop%20presentation%201
%20-%20Roland%20Liemberger.pdf (Accessed 28-Aug-08).
Longley, Alison. Asbestos in drinking water. Seattle, WA: Pacific Sciences Institute.
http://www.mindspring.com/~siccancer/ASBESTOS%20IN%20DRINKING%20WATER.htm
(accessed 2-Sep-08).
Makar, J.M., R. Desnoyers, and S.E. McDonald. 2000. Failure modes and mechanisms in gray
cast iron pipe. Institute for Research in Construction, National Research Council Canada,
Ottawa, Ontario, Canada. Presented at Underground Infrastructure Research 2001 in Waterloo,
R-8
-------
Ontario, June, 10-13. http://ire.nrc-cnrc.gc.ca/pubs/fulltext/nrcc44218/nrcc44218.pdf (accessed
2-Sep-08).
Marshall say, Dene. 2007. Managing water loss at least cost: The economic level of leakage.
Presented at Reducing Non-Revenue Water: Best Practices and Technologies, 2 October 2007, in
Lisbon.
http://www.epal.pt/epal/pdfs/EP ALBritishWaterSeminarOct2007/ll%20Dene%20Marshallsav%
20WRc.pdf (accessed 3-Sep-08).
Matichich, Mike. 2006. Making asset management real and accessible now. Presented during
PNWS-AWWA Webcast, 9-Oct-06.
http://www.pnws-awwa.org/Files/Introduction%20-%20Matichich%20CH2M%20HILL.pdf
(accessed 3-Sep-08).
Mays, Larry W. 1996. Water resources handbook. New York, NY: McGraw-Hill.
McNeill, Laurie S. 2000. Water quality factors influencing iron and lead corrosion in drinking
water. Phd diss., Virginia Polytechnic Institute and State University. Digital Library &
Archives, University Libraries, Virginia Tech.
http://scholar.lib.vt.edu/theses/available/etd-07102000-12010045 (accessed 2-Sep-08).
MDE (Maryland Department of the Environment). 2003. Developing and implementing a water
conservation plan. Baltimore, Maryland: Maryland Department of the Environment Water
Supply Program.
http://www.mde.state.md.us/assets/document/water cons/wcp guidance2003.pdf (accessed 3-
Sep-08).
Merritt, Frederick S., M. Kent Loftin, and Jonathan T. Ricketts. 1996. Standard handbook for
civil engineers, 4th ed. New York, NY: McGraw-Hill.
Mills, Samuel, and Dwayne Rathburn. 2006. San Antonio water system 2005 stat book. SAWS
(San Antonio Water System), Infrastructure Planning Department, San Antonio, Texas.
http://www.saws.org/our water/aquifer/StatsBook/docs/2005 StatsBook.pdf (accessed 3-Sep-
08).
Munich Re Group. 2004. Technology for underwriters 22: Locating leaks after water damage.
Miinchen, Germany: Miinchener Ruckversicherungs-Gesellschaft.
http://www.munichre.com/publications/302-00878 en.pdf (accessed 3-Sep-08).
MUS (Morristown Utility Systems). 2007. Water rates. Morristown, TN: MUS.
http://www.morristownutilities.org/water rates.html (accessed 3-Sep-08).
NACE (National Association of Corrosion Engineers). 2008. Cost of corrosion slide
presentation. Houston, TX: NACE, International.
http://events.nace.org/publicaffairs/cost_corr_pres/cost_corrosion.ppt #281,31,Slide 31 (accessed
3-Sep-08).
R-9
-------
Najafi, Mohammad, and Sanjiv B. Gokhale. 2004. Trenchless technology: Pipeline and utility
design, construction, and renewal. New York, NY: McGraw-Hill Professional.
National drought Mitigation Center, Lincoln NE. http://drought.unl.edu/dm/monitor.html
(accessed 5-Aug-08)
NDMC (National Drought Mitigation Center). 2006. Planning for drought. National Drought
Mitigation Center, University of Nebraska, Lincoln.
http: //drought. unl. edu/pl an/pi an. htm (accessed 2-Sep-08).
Neptune Technology Group. 2006. ARBฎ Utility Management Systems for water utilities.
Tallassee, AL: Neptune Technology Group, Inc.
http://www.neptunetg.com/uploadedFiles/BuildSystem.pdf (accessed 3-Sep-08).
New York Leak Detection, Inc. Water & gas leak detection, ground penetrating radar, pipe &
cable locating, pipeline testing, video inspections, fire flow testing, mapping. Jamesville, NY:
NYLD, Inc.
http://wefindleaks.com/?src=overture (accessed 3-Sep-08).
NRC (National Research Council). 2005. Public water supply distribution systems: Assessing
and reducing risks - First report. Washington, DC: The National Academies Press.
NRC-CNRC (National Research Council of Canada). 2008. Water mains: the importance of
inventory and failure data. Construction Innovation 13(1), March 2008.
http://ire.nrc-cnrc.gc.ca/pubs/ci/v 13no 1 /v 13no 1 _6_e.html (accessed 3-Sep-08).
NUS Consulting Group. 2008. 2007-2008 International water report & cost survey. New
York/London/Paris/Dusseldorf/Milan/Johannesburg/Stockholm/Brussels/Sydney/Toronto/Madri
d: National Utility Service, Inc.
http://www.nusconsulting.com/downloads/2008WaterAbridged.pdf (Accessed 26-Aug-08).
O'Brien, Les, et al. 1986. Buster Backflow. Joe Sinardi, art and layout. Gainesville, FL:
Gainesville Regional Utilities. http://www.abpa.org/Doc/PDF/Buster%201%20Sample.pdf
(Accessed 29-Aug-08).
O'Brien, Les. 2006. Your drinking water. TREEO Center, University of Florida.
http://www.mindspring.com/~loben/water.htm (accessed 2-Sep-08).
O'Day, O.K., R. Weiss, S. Chiavari, and D. Blair. 1986. Water Main Evaluation for
Rehabilitation/Replacement. Denver, CO: AWWA Research Foundation and Environmental
Protection Agency.
Ofwat (The Water Services Regulation Authority). 2005. Economic level of leakage.
Birmingham, England, UK: Ofwat.
http://www.ofwat.gov.uk/aptrix/ofwat/publish.nsf/AttachmentsByTitle/disclog 260805.pdf/$FIL
E/disclog 260805.pdf (accessed 3-Sep-08).
R-10
-------
Ofwat (The Water Services Regulation Authority). 2007. International comparison of water and
sewerage service 2007 report. Birmingham, England, UK: Ofwat.
http://www.ofwat.gov.uk/publish.nsf/AttachmentsByTitle/int_comparison2007.pdf/$FILE/int_co
mparison2007.pdf (accessed 3-Sep-08).
OPS (Ontario Provincial Standards for Roads and Public Works). 2005. Construction
specifications for cement mortal lining of water mains. Ontario provincial standard specification
OPSS 462, November, 2005. Waterloo, Ontario, Canada: University of Waterloo, Department of
Civil Engineering.
http://www.civil.uwaterloo.ca/catt/Pdfs/OPSS462Nov05.pdf (accessed 3-Sep-08).
Oxford Plastics, Inc. 2008. Polyethylene Pipe - A Brief History of Poly Pipe. Ontario, Canada:
Oxford Plastics, Inc.
http://www.oxfordplasticsinc.com/polvethylene.htm (accessed 2-Sep-08).
Parrott, Ralph W., H. Loyd Thornton. 2003. Proprietary tracer gas hydro-test leak detection
system saves time, money. Pipeline & Gas Journal, March, 2003.
http://fmdarticles.eom/p/articles/mi m325 I/is 3 230/ai n25064998 (accessed 2-Sep-08).
Pearson, D. and S W Trow. 2005. Calculating Economic Levels of Leakage. From Leakage
2005 - Conference Proceedings.
http://waterloss2007.com/Leakage2005. com/pdf/Calculating%20Economic%20Levels%20of%2
OLeakage.pdf (accessed 3-Sep-08).
Pilcher, R., S. Hamilton, H. Chapman, D. Field, B. Ristovski, and S. Stapely. 2007. IWA leak
location and repair guidance notes. IWA Specialist Group, Efficient Operation and
Management, Water Loss Task Force.
http://www.leakageforum.org/index.php?option=com_docman&task=doc_details&gid=71&Item
id=33 (accessed 3-Sep-08).
Plastics Pipe Institute. Smooth-wall High-Density Polyethylene pipe systems, 9M 4/2000 PP.
Washington, DC: Plastics Pipe Institute.
www.plasticpipe.org/pdf/high_density_polyethylene_pipe_systems.pdf (accessed 2-Sep-08).
PolyPipe, Inc. 2007. Polyethyline pipe - Municipal water pipe. Gainesville, TX: PolyPipe, Inc.
http://www.polypipeinc.com/municipalwater.asp (accessed 3-Sep-08).
PPFA (Plastic Pipe and Fittings Association) . CPVC products - frequently asked questions.
Glen Ellyn, Illinois: Plastic Pipe and Fittings Association.
http://www.ppfahome.org/cpvc/faqcpvc.html (2-Sep-08).
Propex Services, LLC. Polybutylene piping. Asheville, NC: Propex Services, LLC.
http://www.propex.com/Cf env_polvbu.htm (accessed 3-Sep-08).
Propex. 2005. Polybutylene piping, plumbing - Environmental hazard. Asheville, NC: Propex
Services, LLC.
http://www.propex.com/C_f_env_polybu.htm (2-Sep-08).
R-ll
-------
QDNR (Queensland Department of Natural Resources). 2000. Improving water use efficiency
in Queensland's urban communities. Brisbane, Queensland: QDNR.
http://www.nrw.qld.gov.au/compliance/wic/pdf/reports/urban_wateruse/07_leakage_red.pdf
(accessed 3-Sep-08).
Rajani, B., and S. McDonald. 1994. Water mains break data on different pipe materials for
1992 and 1993. Ontario, Canada: NRC-CNRC (National Research Council of Canada).
http://www.ipexinc.com/Content/EN_CA/4_0_Thermo_Today/4_3_Economie/Water_Mains_Br
eak (accessed 3-Sep-08).
Reiber, Steve. 2005. The changing face of distribution system management. Water & Wastes
Digest 45(12), December 2005.
http://www.waterinfocenter.com/The-Changing-Face-of-Distribution-System-Management-
article6558 (accessed 3-Sep-08).
Repipe News. What you need to know about polybutylene plumbing. Herndon, VA:
Repip enews. com.
http://www.repipenews.com (accessed 2-Sep-08).
Robeyns, J. and P. Vanspeybroeck. 2005. Molecular oriented PVC (MOPVC) and PVC-U pipes
for pressure applications in the water industry. Plastics, Rubber and Composites 34(7):318-323.
http://www.pvc4pipes.org/documents/files/PXII/sess4b/Vanspeybroeck.pdf (accessed 2-Sep-08).
Rowett Research Institute. Body composition. Rowett Institute of Nutrition and Health, The
University of Aberdeen.
http://www.rowett.ac.uk/edu_web/sec_pup/body _comp.pdf (accessed 2-Sep-08).
Selvakumar, A., Clark, R.M., and Sivaganesan, M. 2002. Cost for water supply distribution
system rehabilitation. USEPA, EPA/600/JA-02/406.
http://www.epa.gov/nrmrl/pubs/600ia02406/600ia02406.pdf (accessed 3-Sep-08).
Sensus Metering Systems. Potable water meter test kits, SM-767. Sensus North American AMI
.http://na.sensus.com/Module/Catalog/File/water?id=226 (accessed 2-Sep-08).
Sigma Hellas, Limited. 2005. Correlators. Piraeus, Greece: Sigma Hellas, Ltd.
http://www. sigmahellas.gr/sectors/water wastewater/Special equipment/special categories/corr
elators.htm (accessed 3-Sep-08).
Sj0vold, Fraydis, SINTEF; Peter Mobbs, WRc; SGI. 2005. TILDE- Tools for Integrated Leak
Detection - D20 Benchmarking Tools. EC Contract No. IPS-2001-42077 TILDE. Brussels:
European Commission.
http://www.waterportal.com/comunication/document/D20Benchmarkingtools.pdf (Accessed 28-
Aug-08).
Stephens, Ian. 2002. Economic levels of leakage. Presented at the International Conference on
Water Loss Reduction and Control Programs in Water Supply Systems, 2-3 December 2002.
http://www.ofwat.gov.uk/aptrix/ofwat/publish.nsf/AttachmentsByTitle/is_021202.ppt/$FILE/is_
021202.ppt.ppt (accessed 3-Sep-08).
R-12
-------
Stratus Consulting. 1998. Infrastructure Needs for the Public Water Supply Sector. Report for
American Water Works Association. Boulder, CO. December.
Strosser, P., J. Roussard, B. Grandmougin, M. Kossida, I. Kyriazopoulou, J. Berbel, S. Kolberg,
J.A. Rodriguez-Diaz, P. Montesinos, J. Joyce, T. Dworak, M. Berglund, C. Laaser. 2007. EU
water saving potential (Part 2 - case studies) Institute for International and European
Environmental Policy, ENV.D.2/ETU/2007/0001r, July 19, 2007.
http://ec.europa.eu/environment/water/quantity/pdf/water_saving_2.pdf (accessed 3-Sep-08).
SubSurface Leak Detect!on, Inc. 2006. LC-2500 leak noise correlator. San Jose, California:
SubSurface Leak Detection, Inc.
http://www.subsurfaceleak.eom/lc2500_prod_pg.html (accessed 3-Sep-08).
Sutler County, California. 2008. Section 6: Domestic water supply system. In Sutler County
design standards document. Sutler County Water Resources Division.
http://www.co.sutler. ca.us/pdf/pw/design_standards/DS9_Section_6_Water_Supply.pdf
(accessed 3-Sep-08).
Tangram Technology Ltd. 2004. PVC-u or PVC-U? Whal's in a name? Hilchin, Herts, UK:
Tangram Technology Lid. http://www.langram.co.uk/TI-PVC-U.hlml (accessed 2-Sep-08).
Tangram Technology Lid. 2008. Polymer names. Hilchin, Herts, UK: Tangram Technology
Lid. http://www.langram.co.uk/TI-Polymer-Names.hlml (accessed 2-Sep-08).
Talro, Margie. 2004. A systems view of Ihe nation's energy fulure. Albuquerque, NM: Sandia
National Laboratories.
www.sleab.org/docs/handoul_alba_2004_l 1 _lalro.ppl (accessed 20-Aug-08).
Talro, Margie. 2007. Realizing North America's energy security for Ihe fulure. Albuquerque,
NM: Sandia National Laborilories.
http://northamericaninslilule.org/files/svmposia/lalro-energv-ppl.pdf (accessed 21-Aug-08).
The Engineering Toolbox. 2005. Leakage Classifications of Conlrol Valves.
Engineeringloolb ox. com.
http://www.engineeringloolbox.com/conlrol-valves-leakage-d_484.hlml (2-Sep-08).
Thornton International Lid. 2005. Melropolilan Nashville Water Services (MWS) water audil
and leakage managemenl projecls, USA 2003 to 2009. Sao Paulo, Brazil: Thornton International
Lid. http://www.water-auditcom/WorldProjecls.hlm#Nashville (accessed2-Sep-08).
Thornton, J., R. Sturm, G. Kunkel. 2008. Water loss conlrol, 2nd edition. New York, NY:
McGraw-Hill.
Trevelyana, J., and H.P. Hack. 1994. Analysis of slray currenl corrosion problems using Ihe
boundary elemenl melhod. In Boundary element technology IX, C A Brebbia and A J Kassab,
eds., pp. 348-356. Soulhamplon; Boston: Compulalional Mechanics Publications.
R-13
-------
Tullmin, M. 2007. Waterless. Water pages (Corrosion-club.com). Tullmin Consulting.
http://www.corrosion-club.com/waterfigures.htm (accessed 3-Sep-08).
Turner Designs. Rhodamine WT and fluorescent tracer dye application notes; Fluorescent tracer
studies. Turner Designs, Inc.
http://www.turnerdesigns.com/t2/doc/appnotes/tracer_dye.html (2-Sep-08).
TWDB (Texas Water Development Board) and Mark Mathis. 2005. Water Loss Manual.
Austin, Texas: Texas Water Development Board.
http://www.twdb.state.tx.us/assistance/conservation/Municipal/Water Audit/Leak Detection/Wa
terLossManual_2005.pdf (accessed 29-Aug-08).
Twedt, Steve. 2002. A sea of drinking water lost between treatment, tap. Pittsburgh Post-
Gazette website (Post-gazette.com), July 15, 2002, Health & Science, Environment Section.
http://www.post-gazette.com/healthscience/20020715water0715pl.asp (accessed 3-Sep-08)
Twedt, Steve. 2002. The water system can be taken for granted, until it goes bad close to home.
Pittsburgh Post-Gazette website (Post-gazette.com), July 15, 2002, Health & Science,
Environment Section.
http://www.post-gazette.com/healthscience/20020715breaks0715p3.asp (accessed 3-Sep-08).
US Army. 1986. Technical Manual TM 5-813-5/AFM 88-10, Vol. 5, Water supply, water
distribution. US Army and US Air Force Joint Departments.
http://www.army.mil/usapa/eng/DR_pubs/dr_a/pdf/tm5_813_5.pdf (Accessed 29-Aug-08).
US Army. 1992. Water supply: Pumping stations,Technical Manual No. 5-813-6. Washington,
DC: Headquarters, Department of the Army.
http://www.wbdg.org/ccb/ARCHIVES/ARMYCOE/COETM/tm 5 813 9.pdf (accessed 2-Sep-
08).
US Army Corps of Engineers (USACE), 2001. Washington, D.C., CEMP-R, Public Works
Technical Bulletin 420-49-36 - Leak Detection",
http://www.wbdg.org/ccb/ARMYCOE/PWTB/pwtb 420 49 36.pdf. (accessed 2-Sep-08).
UKSTT (United Kingdom Society for Trenchless Technology). 2005. Lining techniques.
Warwickshire, UK: UKSTT.
http://www.ukstt.org.uk/trenchless_technology/lining_techniques/ (accessed 3-Sep-08).
United Nations Environment Programme, Global Environment Outlook (2000) Chapter 2,
Regional Synthesis http://www.unep.org/geo2000/english/index.htm
USEPA (US Environmental Protection Agency). 2002. Cases in water conservation. Office of
Water (4204M), EPA/832-B-02-003.
http://www.epa.gov/watersense/docs/utilityconservation 508.pdf (accessed 3-Sep-08).
USEPA (US Environmental Protection Agency). 2002. Community water system survey (2000)
Vol. 1. Office of Water (4607M)EPA/815-R-02-005 A, December 2002".
http://www.epa.gov/ogwdw/consumer/pdf/cwss_2000_volume_i.pdf (accessed 3-Sep-08).
R-14
-------
USEPA (US Environmental Protection Agency). 2002. Deteriorating buried infrastructure
management challenges and strategies. Office of Water (4601M), Office of Ground Water and
Drinking Water, Distribution System Issue Paper.
http://www.epa.gov/safewater/disinfection/tcr/pdfs/whitepaper tcr infrastructure.pdf (accessed
3-Sep-08).
USEPA (US Environmental Protection Agency). 2003. Small drinking water systems
handbook. Water Supply and Water Resources Division (WSWRD), National Risk Management
Research Laboratory, Office of Research & Development, EPA/600/R-03/041 May 2003.
www.epa.gov/nrmrl/pubs/600r03041/600r03041.pdf (accessed 3-Sep-08).
USEPA (US Environmental Protection Agency). 2005. Drinking water infrastructure needs
survey and assessment. Office of Water (4606) EPA/816-R-05-001.
http://www.epa.gov/safewater/needssurvey/pdfs/2003/report needssurvey 2003.pdf (Accessed
29-Aug-08).
USEPA (US Environmental Protection Agency). 2005. Water distribution system analysis:
Field studies, modeling and management. Office of Research and Development, National Risk
Management Research Laboratory, Water Supply and Water Resources Division, EPA/600/R-
06/028. http://www.epa.gov/nrmrl/pubs/600r06028/600r06028.pdf (Accessed 3-Sep-08).
USEPA (US Environmental Protection Agency). 2006. Distribution system indicators of
drinking water quality. Office of Water (4601M) Office of Ground Water and Drinking Water
Total Coliform Rule Issue Paper, December, 2006.
http://www.epa.gov/safewater/disinfection/tcr/pdfs/issuepaper_tcr_indicators.pdf (accessed 3-
Sep-08).
USEPA (US Environmental Protection Agency). 2007. Aging water infrastructure research
program: Addressing the problem through innovation. Office of Research and Development,
National Risk Management Research Laboratory, EPA/600/F-07/015.
http://www.epa.gov/ORD/NRMRL/pubs/600f07015/600f07015.pdf (Accessed 29-Aug-08).
US Census Bureau http://www.census.gov/main/www/cen2000.html accessed August 2008
USEPA (US Environmental Protection Agency). 2007. Distribution system inventory, integrity
and water quality. Office of Ground Water and Drinking Water.
http://www.epa.gov/OGWDW/disinfection/tcr/pdfs/issuepaper tcr ds-inventory.pdf (Accessed
27-Aug-08).
USEPA (US Environmental Protection Agency). 2007. Small drinking water systems: State of
the industry and treatment technologies to meet the safe drinking water act requirements. Water
Supply and Water Resources Division, National Risk Management Research Laboratory,
EPA/600/R-07/110, September 2007.
http://www.epa.gov/nrmrl/pubs/600r07110/600r07110.pdf (accessed 3-Sep-08).
USEPA (US Environmental Protection Agency). 2008. Small public water systems and
capacity development. EPA.gov website, Water, Ground Water & Drinking Water, Small Public
R-15
-------
Water Systems Section.
http://www.epa.gov/safewater/smallsvstems/managementhelp.html (accessed 3-Sep-08).
USEPA (US Environmental Protection Agency). 2008. Sustainable infrastructure for water &
wastewater. EPA.gov website, Energy and Water Section.
http://www.epa.gov/waterinfrastructure/bettermanagement_energy.html (accessed 3-Sep-08).
USEPA (US Environmental Protection Agency). 2008. Water quality in small community
distribution systems. Office of Research and Development, National Risk Management
Research Laboratory, Water Supply and Water Resources Division, EPA/600/R-08/039.
http://www.epa.gov/nrmrl/pubs/600r08039/600r08039.pdf (Accessed 29-Aug-08).
USEPA (US Environmental Protection Agency). Decision-support tools for predicting the
performance of water distribution and wastewater collection systems. National Risk
Management Research Laboratory, Office of Research and Development EPA/600/R-02/029.
http://www.epa.gov/nrmrl/pubs/600r02029/600R02029.pdf (accessed 3-Sep-08).
USEPA (US Environmental Protection Agency). Drinking water data & databases. Water,
Ground Water and Drinking Water Section.
http://www.epa.gov/safewater/databases/index.html (accessed 3-Sep-08).
Velan, Inc. 2003. Valve leakage. Williston, VT: Velan Field Engineering Services.
http://www.valvediagnostics.com/leakage/index.htm (accessed 2-Sep-08).
Vinidex Systems & Solutions. Supermain PVC-O. Reece Australia Limited.
http://www.reece.com.au/new/pdf/products/Supermain PVC-O.pdf?civil (accessed 2-Sep-08).
WQHC (The Water Quality & Health Council). 2008. Safe water delivered safely.
Waterandhealth. org.
http://www.waterandhealth.org/drinkingwater/safewater.html (accessed 3-Sep-08).
WRRC (Water Resources Research Center). 1994. Leaks Plague Polybutylene Plumbing.
Water Resources Research Center, the University of Arizona.
http://ag.arizona.edu/AZWATER/awr/nov94/leaks.html (accessed 2-Sep-08).
WSSC (Washington Suburban Sanitary Commission). WSSC water meter tests (5/8" - VA"
Meters). Laurel, Maryland: WSSC.
http://www.wssc.dst.md.us/service/MeterTesting.cfm (accessed 3-Sep-08).
Yu, Myong-jin, Mi-jeong Jang, Sanghyuck Park, Byoung-kwon Park, and Ja-yong Koo. 2007.
Application of CIPP (cured in place pipe) for water pipe rehabilitation. Dept. of Environmental
Engineering, University of Seoul, Korea. Paper presented at the ROMA07 Mediterranean
NODIG XXV International Conference & Exhibition, October 10-12, 2007.
http://www.iattmed.com/pdf/s3 11 Myong.pdf (accessed 2-Sep-08).
Zhao, J.Q. 2003. Slipline rehabilitation of water mains with high-density polyethylene pipe.
Construction Technology Update No. 56, Jan. 2003.
http://irc.nrc-cnrc.gc.ca/pubs/ctus/56_e.html (accessed 29-Aug-08).
R-16
-------
Cook, Jack S. 2008. Mapping water losses - A success story. VI Magazine
(Vectorlmedia.com), Articles Section, http://www.vectorlmedia.com/article/column/mapping-
water-losses-%96-a-success-story/ (accessed 4-Sep-08).
Wu, Zheng Yi, and Paul Sage. 2006. Water loss detection via genetic algorithm optimization-
based model calibration. Presented at the ASCE 8th Annual International Symposium on Water
Distribution System Analysis, August 27-30, 2006, in Cincinnati, OH.
www.genetic-programming.org/hc2006/Wu-Paper-2.pdf (accessed 4-Sep-08).
MDE (Maryland Department of the Environment). 2003. Water supply program water audit
guidance. Maryland Department of the Environment, Water Supply Program.
www.mde.state.md.us/assets/document/water cons/Water Audit guidance.pdf (accessed 4-Sep-
08).
PSC (Public Service Commission of Wisconsin). 2006. Water - The Wisconsin numbers.
Madison, Wisconsin: PSC.
www.psc.wi.gov/utilitvinfo/water/newsinfo/document/waterWiNumbers2005.pdf (accessed 4-
Sep-08).
R-17
------- |