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
- This rulemaking started December 24, 2021.
- A Board Hearing was held on October 19, 2022
- Rulemaking documents will be posted in the Complete Rulemaking File as they are released.
- Inquiries regarding the contents of this regulation may be directed to WaterLossControl@Waterboards.ca.gov .
- The Board Hearing was held on February 10, 2022 at 2pm.
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)
Questionnaires
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.
CEQA
View the CEQA Negative Declaration.
Documents Released for August 17th Board Meeting
- Draft Regulation Text (Released August 8, 2022)
- Updated Model and Standards
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
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
Presentations
Revised Economic Model: Water Loss Performance Standards
Revised Regulatory Proposal and Process: Water Loss Performance Standards
Reference materials:
- Fact sheet with overview of regulatory proposal and timeline
- Draft economic model to calculate water loss standards
- Summary of changes to economic model
- Draft Guidance to draft economic model
- Draft proposed water loss standards using default values in economic model
- Questionnaires on:
- Draft regulatory text
- Proposed alternative compliance pathway for existing low loss
- Draft Initial Statement of Reasons
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.
Materials for comment:
- Proposed Water Loss Performance Standards: Overview and Timeline
- Draft economic model for calculating volumetric standards (second version) (The model contains proposed default values for inputs and uses example values for supplier-specific input values from water loss audits - see item 6 for all values)
- Questionnaires for data submission requirements of the proposal on:
- Overview of proposed off-ramp provision
- Summary of current leakage and proposed draft volumetric standards for urban retail water suppliers
- Input values from water loss audits used to calculate proposed draft standards
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
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.)
- Overview of framework
- Reference document describing preliminary assumptions and proposals for standard development
- Initial assumptions and considerations for calculations of benefits and costs for the economic model
- Calculation of standards, overview of compliance requirements and low water loss values
- Adjustments and variance process
February 1 and 4, 2019 - Public Stakeholder Meetings #4, Sacramento and Chino
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.
- Staff proposal for framework of water loss performance standards
- Staff presentations:
Framework overview | Adjustments and Compliance | Economic basis
September 17, 2018 - Public Stakeholder Meeting #3, Los Angeles
Presentations:
- Avoided Cost of Water, State Water Resources Control Board
- IRWD’s Water Loss Control Programs and Cost-Effectiveness, Irvine Ranch Water District
- Water Loss Control in Los Angeles, LA Department of Water & Power
- Overview of Life Cycle Cost Assessment: Case Study of LCA Alternatives Assessment of Lead-Free Cast Brass for the Potable Water Supply Components, University of California Los Angeles
June 1, 2018 - Public Stakeholder Meeting #2
- Monitoring and Estimation Technologies | Pressure management | Technology-Constraint Matrix, State Water Resources Control Board
- Machine learning and Pipeline Replacement Prioritization, East Bay Municipal Utility District
March 9, 2018 - Public Stakeholder Meeting #1, Sacramento
- Water audit data and topics, State Water Resources Control Board
- Water Loss TAP findings, WSO
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.
Resources
State Assistance and Efforts
- Drinking Water State Revolving Fund
- Resources from the State-funded Water Loss TAP (California-Nevada AWWA)
- DWR’s Regional Offices for leak detection equipment for short-term lease under ‘Technical Assistance’
- Memorandum of Understanding between California and Denmark
Auditing, Validation and Control Strategies
- Free AWWA water audit software from the AWWA Water Loss Control Committee
- Fact Sheet on water loss control by the Water Research Foundation
- Manuals for validation guidance and concepts by the Water Research Foundation
- Resources from the Natural Resources Defense Council
- Alliance for Water Efficiency Library on water loss control