United States has been in service for decades and can be a significant source of water
loss [2]. 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 [6–13].
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 [2]:
1. Water audit
2. Intervention
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% 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 [2]. 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, 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 provides
detailed quantification of the implemented methodology. For example, the pipe
replacement resulted in a reduction of water losses of so many gallons per customer
per year of performance indicators. 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
6 Water Losses from Utilities
241
loss [2]. 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 [6–13].
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 [2]:
1. Water audit
2. Intervention
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% 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 [2]. 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, 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 provides
detailed quantification of the implemented methodology. For example, the pipe
replacement resulted in a reduction of water losses of so many gallons per customer
per year of performance indicators. 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
6 Water Losses from Utilities
241