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Water Loss Control

California Water Code Section 10608.34 requires the State Water Board to develop water loss performance standards for urban retail water suppliers. Executive Orders B-37-16 and B-40-17 direct the State Water Board and Department of Water Resources (DWR) to minimize water waste through system leaks.

Rulemaking Status: Complete

Water Loss Model, Standards, and Questionnaires

Updated Water Loss Model (Released September 2, 2022)

Model Equation Changes (Released September 2, 2022)

Individual System Water Loss Standards (Released August 22, 2023)


Urban retail water suppliers are required to complete questionnaires administered by the State Water Resource Control Board (California Code of Regulations, title 23, division 3, chapter 3.5, section 983). The deadline for submitting the data quality and pressure management questionnaires has been extended to December 31, 2023. If a supplier has multiple systems, it must complete this questionnaire once for each system.

Data Quality Questionnaire
This system-level questionnaire asks for information on flow testing of production meters, electronic calibration, flow testing of customer meters.
A summary of the questions in the data quality questionnaire is available here

Pressure Management Questionnaire
This system-level questionnaire asks for information on pressure control devices and high leakage zones.
A summary of the questions in the pressure management questionnaire is available here

Data Quality Excel Submission
The Data Quality Excel Submission is a component of the Data Quality Questionnaire. Please refer to the Data Quality Questionnaire for instructions regarding the Data Quality Excel Submission.


Documents Released for August 17th Board Meeting

Staff Workshop on January 11, 2022

Water Loss Performance Standards Workshop - January 11, 2022 (YouTube)

Purposed of Workshop

  • To explain the proposed regulation and standards
  • To communicate the ways interested parties can be involved in the formal rulemaking process
  • To explain how suppliers can submit updates to default data
  • To answer quesitons

Peer Review

A peer review of the Economic Model was completed on December 28, 2020. Both the Peer Review and Staff’s Summary and Responses to the Peer Review are available.

Directions for Updating Default Parameters

Default parameters in the Economic model may be updated to incorporate supplier-specific information. While updates may be submitted until July 1, 2023, we are asking that suppliers submit requests as soon as possible. An updated guidance document is available for reference.

  To submit a request, please email ORPP-WaterLossControl@Waterboards.ca.gov.

Pre-rulemaking Meetings and Workshops

April 15, 2021 - Updated Economic Model

Memo for Economic Model Release

Revised Economic Model

March 24, 2021 - Public Stakeholder Webinar


Documents for March 24 Staff Workshop on Water Loss

Attached are the peer reviews and a staff summary that will be discussed at the workshop on March 24 from 1:00pm-3:00pm. For questions about these documents or the workshop, please contact Bethany Robinson at Bethany.Robinson@waterboards.ca.gov

Water Loss Staff Summary of Peer Reviews
Water Loss Peer Reviews

December 16, 2020 - Public Stakeholder Webinar

Agenda | Notice

May 13, 2020 - Public Stakeholder Webinar

Agenda | Revised Notice (Comment period extended to June 12, 2020) | Notice

Voluntary questionnaire for additional information on water loss audits

The purpose of the voluntary questionnaire is to support the State Water Board’s efforts towards assessing and establishing the reliability of and confidence in the water loss estimates reported in the water loss audits.

September 23, 2019 - Public Stakeholder Meeting #6

Agenda | Revised Notice | Notice

Reference material for the workshop was circulated through State Water Board’s conservation list serve. Sign up for the email list at https://www.waterboards.ca.gov/resources/email_subscriptions/swrcb_subscribe.html

June 7, 2019 - Public Stakeholder Meeting #5, Sacramento

Agenda | Notice

Materials for workshop (Uploaded June 11, 2019): The uploaded materials are documents that were shared during or prior to the workshop. The following materials are subject to changes based on stakeholder input, as the stakeholder process is ongoing.)

February 1 and 4, 2019 - Public Stakeholder Meetings #4, Sacramento and Chino

Agenda | Notice

The uploaded materials are documents that were shared during or prior to the workshop. The following materials are subject to changes based on stakeholder input, as the stakeholder process is ongoing.

September 17, 2018 - Public Stakeholder Meeting #3, Los Angeles

Agenda | Notice


June 1, 2018 - Public Stakeholder Meeting #2

Agenda | Notice

March 9, 2018 - Public Stakeholder Meeting #1, Sacramento


Water Loss Auditing

California Water Code Section 10608.34 requires urban retail water suppliers to conduct and submit validated water loss audit reports to the Department of Water Resources (DWR) on October 1, annually. More information is available on DWR’s water loss program page. Previously submitted water loss audits can be downloaded individually or as a group.

California Water Code Section 10631 requires all urban water suppliers to submit water loss audits with their Urban Water Management Plans every five years to DWR.

Senate Bill 555 requires that water loss audits be validated before they are submitted to DWR. Subsequent regulations specify that validations may only be performed by a certified water audit validator. CA-NV AWWA’s Water Loss Collaborative has more information on the Water Audit Validator Certificate Program.

Technical Assistance

The State Water Resources Control Board awarded $3.2 million in funding in January 2016 for technical assistance programs for water suppliers to effectively conduct and validate water loss audits and comply with SB 555, through the formation of the California Water Loss Collaborative. The Water Loss Technical Assistance Program (TAP) provided training and validation to initiate California’s validated water loss auditing process.


State Assistance and Efforts

Auditing, Validation and Control Strategies