Guest Column | November 1, 2019

Water Loss Control — From Audit To Action

By Sue Mosburg


Non-revenue water loss is a problem from coast to coast, but California has taken a lead and set an example — with resources from AWWA — by adopting and sharing best practices to help solve the issue.

There’s no simple solution to ensure that the maximum volume of water entering a potable water distribution system reaches customers. However, conducting an annual water loss audit and having it Level 1 validated, are essential first steps. Over time, annual water audits can be used to measure the success of water loss control programs and guide decision-making to determine which interventions are most appropriate and economically justified.

October 1, 2019 marked the third consecutive year in which validated water loss audits have been required of California’s urban retail water systems, per compliance with Senate Bill 555 — Urban retail water suppliers: water loss management (SB 555). For the first round of audits in 2017, affected water systems received assistance through the American Water Works Association’s California-Nevada Section’s (CA-NV AWWA) Water Loss Technical Assistance Program (WL TAP). Affected water systems are now on their own to compile the audit, ensure that it’s validated, and submit required documentation to California’s Department of Water Resources (DWR). Because data is typically owned by different departments, water suppliers are encouraged to adopt team approaches when compiling their audits and developing comprehensive water loss control plans.

Beginning With A Water Audit

AWWA’s M36 manual, Water Audits and Loss Control Programs, defines water loss as the difference between the volumes of water supplied to a system and the authorized consumption within that system. Water loss control therefore represents the efforts of water utilities to provide accountability in their operations by reliably auditing their water supplies and implementing controls to minimize water distribution system losses. This includes activities to reduce system leakage to economically achievable levels and also activities to reduce metering and billing errors so that reliable measures of water supplied to the system, water used for system maintenance activities, and customer consumption are attained.

Utilities incur real (physical) losses from pipeline leakage, storage tank overflows, etc., and apparent (non-physical) losses when volumes are not properly measured or billed. In the last decade, the wave of understanding of and appreciation for water loss auditing has swept across North America. Led by Georgia and California, several states have enacted legislation and/or introduced bills requiring annual water loss audits. A website developed by the Natural Resources Defense Council provides a comprehensive overview of statewide actions taken to date. In developing statewide requirements, regulators, water systems, and other stakeholders are advocating the water audit method developed jointly by the International Water Association (IWA) and AWWA. The IWA/AWWA Water Audit Method provides the best management practice tools and guidance water utilities need to efficiently manage their supplies.

Built on the methodology detailed in M36, AWWA’s Free Water Audit Software1 is the industry standard for identifying and categorizing water volumes entering a system, while simultaneously assessing operational efficiency and accounting practices. In California, water loss audits submitted to DWR must be compiled using AWWA’s software and must be Level 1 validated following criteria established by the Water Research Foundation (WRF) in Project 46392 (2016).

Water Audits Must Be Validated

WRF Project 4639 was structured to provide North American water utilities and regulatory entities with clear guidance and a standardized methodology for validation of water audit data. To validate an audit at Level 1, the water loss expert reviews the data entered and the associated data grades and discusses business and operational practices with the audit preparation team. Validation does not make data inputs or grades “right” or “wrong” but merely aligns them with the actual conditions that occurred in the operation of the utility for the audit year. Any discrepancies noted during validation are discussed between the audit team and the validator, then documented in a validation report.

Level 1 validation results in a better understanding of the data and business practices informing the audit and is currently required in California, Georgia, and Hawaii. In California, a water supplier may validate its own audit, provided that the individual performing the validation did not also participate in compiling it. All validators must meet the requirements set forth in California water code (23 CCR § 638).3 After June 30, 2019, this means all validators must hold a Water Audit Validator (WAV) certificate issued by CA-NV AWWA. WAV information and listing of current certificate holders is posted on the Section’s website.4 For those with a solid foundation in water loss auditing, WAV’s two-day classes are regularly scheduled by CA-NV AWWA across California.

Performance Benchmark Development

SB 555 requires the California State Water Resources Control Board (SWRCB), by July 1, 2020, to adopt rules for achieving volumetric water loss performance standards. In adopting these rules, the board shall employ full lifecycle cost accounting. As a result, SWRCB staff have been reviewing water loss audit data and collecting information through the electronic “Annual Report,” and they have held a series of informal workshops to collect stakeholders’ input on a proposed four-phase approach aligned with the implementation time line of Senate Bill 606 and Assembly Bill 1668, which will set the overall water efficiency targets for California’s urban retail water systems by 2035.

The following four phases have been proposed for the water loss framework:

  • Phase 1 – Understanding water losses through improved data collection and understanding of the data
  • Phase 2 – Determining and piloting effective approaches and initial implementation of a volumetric performance standard
  • Phase 3 – System-wide water loss reduction and performance standard refinement
  • Phase 4 – Continued water loss control.

The challenges faced in developing a workable performance standard are numerous. Regulators are attempting to strike a balance between achieving California’s water stewardship goals and creating reasonable standards that don’t place an enormous and unreasonable burden on water systems. Questions to be answered include: Is there sufficient data upon which to set performance standards? Should a single statewide volumetric standard be set, or should a unique standard be set for each water system? How should annual audit variability be addressed? At what point should compliance be required? How good is good enough? Should a performance standard include required operational elements or only be set on volume of losses? At what point in the setting of performance standards should cost-effectiveness be considered?

Take Action Now

What is clear is that a better understanding of water distribution system pressures and the components of real losses unique to each system is needed. The proposed framework therefore includes a requirement for water systems to employ effective pressure monitoring and also requires water systems to complete a system-wide component analysis using the Leakage Component Analysis Model5 (developed as part of WRF project 43726 ) multiple times prior to 2027. With formal rulemaking set to begin later this year, and with the SB 555 requirement to include with each audit submission a list of actions taken to reduce losses and improve data validity, the time is now to bring your water system’s water loss team together to develop a water loss control plan. To help you, “Water Research Foundation Project 4695 - Guidance on Implementing an Effective Water Loss Control Plan”7 was released earlier this year.

About The Author

Sue Mosburg, program manager at Sweetwater Authority, chairs the American Water Works Association’s California-Nevada Section’s Water Loss Control Committee and sits on the Section’s Executive Committee as association director.