development sectors. The current implicit global assumption that water
management institutions can be improved unilaterally when other development sectors remain somewhat inefficient is simply not a viable proposition.
7 Water Auditing: An Integral Element of a Demand
Management Strategy
A water audit is an accounting of all of the water in a water system resulting in a
quantified understanding of the integrity of the water system and its operations. It is
the first step in formulating an economically sound plan to address water losses.
A preliminary water audit begins with the following information and simple
calculations:
1. Determine the amount of water added to the system, typically for a one-year
period,
2. Determine authorized consumption (billed + unbilled) and
3. Calculate water losses (water losses = system input − authorized consumption)
(a) Estimate apparent losses (unauthorized consumption + customer meter
inaccuracies + billing errors and adjustments)
(b) Calculate real losses (real losses = water losses − apparent losses).
These steps are an example of a top-down approach of an audit, which starts at
the “top” with existing information and records. Water systems are dynamic, and
the water audit process and calculation of the water balance, when routinely performed, is a useful guide for a system’s water loss control program. Water systems
audit can get started using the data that is readily available, identify any data gaps
and then work toward improving the data. After performing an initial top-down
audit, it may become evident that some of the numbers are rough estimates. The
next action in the audit process is to improve any initial estimates and begin
reducing non‐revenue water losses.
A bottom-up audit is often implemented after several top-down audits have been
completed and can better quantify loss volumes that were not revealed by the
top-down audit. A bottom-up audit helps in finding apparent and real losses and
begins by looking at components or discrete areas in the utility’s operations.
A bottom-up audit assesses and verifies the accuracy of the water loss data associated with individual components of the water system.
Additional data collection can occur during the audit or intervention phase and
may include the following:
• Locating leaks and losses can be accomplished through an examination of
billing records, flow monitoring, visual inspection or leak detection equipment
(e.g., acoustic, thermal, electromagnetic and tracer). Through an examination of
40
K. Singh and S. Mahanta
management institutions can be improved unilaterally when other development sectors remain somewhat inefficient is simply not a viable proposition.
7 Water Auditing: An Integral Element of a Demand
Management Strategy
A water audit is an accounting of all of the water in a water system resulting in a
quantified understanding of the integrity of the water system and its operations. It is
the first step in formulating an economically sound plan to address water losses.
A preliminary water audit begins with the following information and simple
calculations:
1. Determine the amount of water added to the system, typically for a one-year
period,
2. Determine authorized consumption (billed + unbilled) and
3. Calculate water losses (water losses = system input − authorized consumption)
(a) Estimate apparent losses (unauthorized consumption + customer meter
inaccuracies + billing errors and adjustments)
(b) Calculate real losses (real losses = water losses − apparent losses).
These steps are an example of a top-down approach of an audit, which starts at
the “top” with existing information and records. Water systems are dynamic, and
the water audit process and calculation of the water balance, when routinely performed, is a useful guide for a system’s water loss control program. Water systems
audit can get started using the data that is readily available, identify any data gaps
and then work toward improving the data. After performing an initial top-down
audit, it may become evident that some of the numbers are rough estimates. The
next action in the audit process is to improve any initial estimates and begin
reducing non‐revenue water losses.
A bottom-up audit is often implemented after several top-down audits have been
completed and can better quantify loss volumes that were not revealed by the
top-down audit. A bottom-up audit helps in finding apparent and real losses and
begins by looking at components or discrete areas in the utility’s operations.
A bottom-up audit assesses and verifies the accuracy of the water loss data associated with individual components of the water system.
Additional data collection can occur during the audit or intervention phase and
may include the following:
• Locating leaks and losses can be accomplished through an examination of
billing records, flow monitoring, visual inspection or leak detection equipment
(e.g., acoustic, thermal, electromagnetic and tracer). Through an examination of
40
K. Singh and S. Mahanta