Water Loss Audit Validation

What is Water Loss Audit Validation?

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 scenarios4. An inaccurate water loss audit may result in an incorrect assessment of water loss performance. Without an accurate understanding of the types and quantities of water loss or the practices contributing to loss, it may not be possible to develop a cost-effective strategy to address the inefficiencies.

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.
  • Evaluate and communicate the uncertainly inherit 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.

Who should perform these validations?

Water loss audit validation should be performed by a person proficient in current American Water Works Association (AWWA) M36 and TWDB water loss audit methodologies and the Water Research Foundation (WRF) 4639 water validation methodology. The validator should not be the same person who compiled the water loss audit. Similar to Georgia, Indiana, and California, three states which require the submission of Level 1 validated water loss audits and have recognized the critical importance of water loss audit validation and over time have created state programs to certify water loss audit validators, TWDB staff will perform required level 1 validations beginning in 2025.

Are utilities required to have their water loss audit validated and by whom?

Effective January 1, 2025, a utility required to submit a water loss audit annually due to a financial obligation to TWDB or that is applying for financial assistance will be required to have its most current water loss audit validated within three months of submittal or prior to consideration of a request for financial assistance from the board. The executive administrator 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 executive administrator. Should a water loss audit be validated by a person other than the executive administrator's staff, validation must follow TWDB's validation guidelines and be performed by a person other than the person submitting the water loss audit, who has completed water loss audit validation training and is certified to conduct such validation.

Validation Resources

  • How to Join a Microsoft Teams Meeting
  • Texas Water Loss Audit Validation Study (2021)

  • For additional information, please contact TWDB's Water Loss Audit team at WLA-Group@twdb.texas.gov or 512-463-0987.