Water Conservation banner

Water Loss Control

California Water Code Section 10608.34 required 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.

Water loss performance standards were developed through a rulemaking that became effective in 2023. Details are below.

As part of a proposed water conservation regulation, urban retail water suppliers - not individual households or businesses - will be held to "urban water use objectives." An urban water use objective is the sum of standard-based budgets for a subset of water uses, such as residential outdoor use.

Read more about how urban retail water suppliers would calculate customized urban water use objectives.

Water going down sink drain
public meetings

Pre-Rulemaking Meetings

Learn more about pre rulemaking workshops and meetings

intervention icon

Water Loss Model, Standards, and Questionnaires

Access the water loss model, individual water system standards, and questionnaires

Regulatory Documents

Regulatory Documents

Find files associated with the official rulemaking process

Fact Sheets

Fact Sheets

Find documents that explain the water loss standards

default parameters

Default Parameters

Find information regarding default parameter adjustments

stay in touch

Stay in Touch

Receive regular updates by signing up for our newsletter.
E-mail us at DDW-WaterLossControl@waterboards.ca.gov .

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.

Default Parameter Adjustments

Directions for Updating Default Parameters

Default parameters in the Economic model may be updated to incorporate supplier-specific information. Additionally, suppliers may request to remove outlier values. Supplier must provide an explanation for default parameters submitted after July 1, 2023. We are asking that suppliers submit requests as soon as possible. An updated guidance document is available for reference.

A reference document for outlier values is available here.

A reference document for economic model inputs is available here.

To submit a request, please email DDW-WaterLossControl@waterboards.ca.gov

Fact Sheets

Please refer to the Frequently Asked Questions document for questions related to the water loss standards and regulation

Please refer to the presentation from the October 2022 board hearing for a summary of the water loss regulation and changes that were made during the rulemaking process.

  Email Subscription Topic

Subscribe to the Water Loss Control Updates email topic to receive notifications and the latest updates.

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


Revised Economic Model: Water Loss Performance Standards
Revised Regulatory Proposal and Process: Water Loss Performance Standards

Reference materials:

  1. Fact sheet with overview of regulatory proposal and timeline
  2. Draft economic model to calculate water loss standards
  3. Summary of changes to economic model
  4. Draft Guidance to draft economic model
  5. Draft proposed water loss standards using default values in economic model
  6. Questionnaires on:
    1. Data quality
    2. Asset management
    3. Pressure management
  7. Draft regulatory text
  8. Proposed alternative compliance pathway for existing low loss
  9. 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:

  1. Proposed Water Loss Performance Standards: Overview and Timeline
  2. 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)
  3. Questionnaires for data submission requirements of the proposal on:
    1. Data quality (Apparent loss)
    2. Asset management
    3. Pressure management
  4. Overview of proposed off-ramp provision
  5. Summary of current leakage and proposed draft volumetric standards for urban retail water suppliers
  6. 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

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