The Water Audit

Similar to financial audits conducted by accountants, the water audit compares volumes of water treated and pumped to volumes consumed by customers, and other uses such as firefighting and community uses. Estimated volumes of losses due to leakage and poor metering and accounting can be quantified in the water audit process. Currently, there is no national requirement for routine water auditing in North America, although a number of state and regional water resources agencies have taken the lead in requiring water audits by water utilities and specifying data validity protocols. See the AWE Water Efficiency and Conservation State Scorecard: An Assessment of Laws, published in 2017.

A reliable water audit methodology was developed jointly by the International Water Association (IWA)  and the American Water Works Association (AWWA)  in 2000, and is described in detail in the AWWA M36 Manual.  The water balance of this methodology shows schematically the various components in which water volumes are tracked.

Water Balance of AWWA/IWA Water Audit Methodology​

The water balance tracks – from left to right – how a water utility supplies water volumes from source to customer, and provides the format for the water utility to quantify the amounts of both billed and lost water.  The most convenient way for a water supplier to compile a water audit is by using the AWWA Free Water Audit Software©.