Using Water Audits to Understand Water Loss

By Abby Crisostomo

Last week, I attended a webinar held by the U.S. EPA called “Using Water Audits to Understand Water Loss” that brought together engineers from the EPA, the American Water Works Association (AWWA), private engineering firms and public utilities to discuss the importance of controlling water loss in drinking water infrastructure. Their focus was to explain water audits and to demonstrate water audit tools and tracking methods for water utilities to use.

Efforts to deal with water scarcity can come from both the supply and the demand side. Here in the Chicagoland region, the amount of drinking water available from the lake is limited by the diversion rules and our groundwater resources are strained. It is difficult to sustainably increase the supply of water available here without jeopardizing the quality of the water. Demand-side options include water conservation and water efficiency, which many of you are already familiar with, but also water loss control from water systems.

Water loss control involves improving knowledge about the water system, intervening to improve conditions, evaluating the results, and repeating. Water loss can come from physical loss, when water leaks from the system, or from apparent loss, when water is consumed, but not billed for. You may have heard the phrases “unaccounted-for flow” or “unaccounted-for water,” but because of their inconsistent and vague interpretation, a more precise and accurate term for physical water loss, plus apparent water loss, plus authorized unbilled water consumption is “non-revenue water.” Not only does reducing the amount of non-revenue water in your system reduce water waste and improve revenue streams, but it can also have the benefit of reducing greenhouse gas emissions through lower electricity fuel use.

The AWWA’s Free Water Audit Software allows system managers to determine the extent of the water loss problem by answering questions about several performance indicators, including financial, operational, apparent losses normalized, real losses normalized and an infrastructure leakage index. The speakers on the webinar shared case studies of a small system in eastern North Carolina and a large system in Philadelphia where water utilities used the AWWA’s water audit software to successfully improve efficiency. Philadelphia was able to recapture an average $2 million dollars a year!

As George Kunkel from the Philadelphia Water Department said at the end of the webinar, “Leading the water loss control program is like conducting an orchestra, directing multiple activities to achieve harmonious performance.” Improving access to clean drinking water takes more than just using less, finding a new source, or using expensive technology to clean contaminated water. Along with those efforts, we should take a hard look at the efficiency of our water infrastructure and billing practices to stop wasting both water and money.

Non-revenue water laid out. Taken from slide by Gary Trachtman for Jan. 26, 2012 webinar.