OCA Audit Reports

Issued: April 2009

This report presents the results of our audit of the reliability of the water loss calculation process followed by the Austin Water Utility. Also included in this report is information on the Utility’s preparedness to report more detailed calculations to the Texas Water Development Board (TWDB) and the calculation of water loss for FY 07.

According to the Texas Water Development Board (TWDB), utilities should measure water loss as an important part of their water conservation measures and activities. In 2003, the State began requiring retail public utilities to provide a water loss calculation to the TWDB once every five years. In response to this mandate, the TWDB published guidance for utilities in their Water Conservation Best Management Practices Guide (BMP Guide) and developed a water loss calculation methodology for utilities that measures efficiency, encourages water accountability, quantifies water losses, and standardizes water loss reporting across the State. TWDB has since updated their guidance to reflect more rigorous methods for estimating water losses.

Our audit objectives included reviewing the process followed by Utility staff in performing Water Loss calculations to determine the Utility’s preparedness to report system water loss according to the current, more rigorous, TWDB guidelines. We also sought to provide a reliable baseline measurement of water loss within the AWU distribution system for FY 07 that can be used to identify and track the success of efforts to minimize that loss.

We found that the Austin Water Utility (AWU) has taken a utility-wide approach to measure and manage water loss, with some positive results. As a part of a broad, Utility-wide initiative focused on water conservation, AWU management created the Water Accountability Group (WAG) in 2006. The WAG was charged with addressing challenges to the measurement of water loss in the City. Using the prevailing methodology supported by TWDB at that time, the WAG performed a calculation to estimate the City’s water loss for FY 05 which fell within acceptable industry standards. The WAG also offered several recommendations to better measure and to decrease the volume of water lost by the City. However, in 2007, progress toward this end stalled, and several of the WAG’s strategies went unimplemented. The new AWU director, who was hired in 2008, revived the WAG, and AWU has moved forward with several of its suggested water loss control strategies.

We also found that AWU has not yet fully implemented the new, best practice method recommended by the TWDB for measuring and managing water loss; however, they have begun taking steps to do so. AWU needs to make additional process changes to fully implement the TWDB-recommended component reliability matrix. Making these changes will enable AWU management to calculate more reliable water loss estimates and take a best practice approach to manage water loss. We also noted improvement opportunities for AWU in terms of tracking and responding to known leaks, and increasing controls over privately owned hydrants.

Using the best practice approach recommended by the TWDB, we estimated that the City lost approximately 5.33 billion gallons or 11 percent of water that it treated in FY 07. This loss, when calculated against the size of the water infrastructure, results in an infrastructure leakage index that is within acceptable industry standards, per American Water Works Association (AWWA) guidelines. The best practices approach we employed and the results we obtained during this audit can be used by AWU as a basis for future planning and benchmarking purposes.

We have offered recommendations that we believe will improve the accuracy, quality, and availability of information for the Utility to use in its planning processes. As of the date of this report, we believe that AWU staff has made good progress toward implementing many of the recommendations as they go forward in preparation for their next required report to the TWDB.

Download the entire text of our AWU Water Loss in Adobe Acrobat. You will need Adobe's Acrobat Reader to view these files. Or request a hard copy of this audit report, No. AU08110, by submitting this audit report request form.

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