Water Loss Audit Validation
- What is water loss audit validation?
- Why validate a water loss audit?
- Who is impacted by House Bill 29?
- Who is required to have their water water loss audit validated?
- Who should perform these validations?
- Validation Resources
For additional information, please contact TWDB's Water Loss Audit team at WLA-Group@twdb.texas.gov or 512-463-0987.
What is water loss audit validation?
Water loss audit validation is the process of examining water loss audit inputs to improve the water loss audit's accuracy and document the uncertainty associated with the used data. The goals of the water loss audit validation are to:
- identify and appropriately correct for errors in water loss audit data and misapplication of methodology; and
- evaluate and communicate the uncertainty inherent in water loss audit data.
There are three levels of validation rigor:
- Level 1: Water loss audits are examined for inaccuracies evident in summary data and application of methodology.
- Level 2: Water loss audits have been corroborated with investigations of raw data and archived reports of instrument accuracy.
- Level 3: Water loss audits have been bolstered by field tests of instrument accuracy and the water loss audit's estimate of Real Loss has been confirmed through other sources of field data, such as with a Component Analysis of Real Loss.
Why validate a water loss audit?
Research on water loss audit data has concluded that utilities often struggle to assess the validity of their own data accurately and consistently, and a substantial portion of audit submissions have reported suspect data that produce technically impossible water loss scenarios. An inaccurate water loss audit may result in an incorrect assessment of water loss performance.
Georgia, Indiana, and California, require the submission of Level 1 validated water loss audits. These three states have recognized the critical importance of water loss audit validation over time and have created state programs to certify water loss audit validators. As of January 2025, Texas also requires water loss valdiations, and TWDB staff performs those level 1 validations.
Who is impacted by House Bill 29?
A municipally owned utility that provides potable water through more than 150,000 service connections, as reflected on their most recent water loss audit, is subject to the requirements of House Bill 29. Based on the 2024 submitted water loss audits, six utilities are impacted:
- City of Austin
- City of El Paso
- City of Fort Worth
- City of Houston
- Dallas Water Utilities
- San Antonio Water System
Learn more about the requirements in the House Bill 29 FAQs.
Who is required to have their water loss audit validated?
There are two instances when a water loss audit should be validated:
- A utility submitting a water loss audit annually that is required due to a financial obligation to TWDB will be required to have its most current water loss audit validated within six months of submittal.
- A utility applying for financial assistance will be required to have its most current water loss audit validated prior to consideration of a request for financial assistance from the Board.
Who should perform these validations?
TWDB staff will validate the submitted water loss audit in conference with the retail public utility. Alternatively, the utility may elect to have the water loss audit validated by a person other than the TWDB staff. Should a water loss audit be validated by a third-party, validation must follow TWDB's validation guidelines and be performed by a person other than the person submitting the water loss audit and who has completed water loss audit validation training and is certified. Overall, the water loss validator should be proficient in current American Water Works Association (AWWA) M36, TWDB water loss audit methodologies, and the Water Research Foundation (WRF) 4639 water validation methodology.