Water Loss Standard

The Basics

  • The water loss standard is derived from separate but related legislation, Senate Bill 55 (2015), which also requires urban water retail suppliers to submit annual validated water audit.
  • The water standard focuses on real losses expressed in gallons per connection per day or gallons per mile (of pipe) per day depending on supplier size.  The vast majority of suppliers will have a standard in gallons per connection per day.
  • Supplier specific 2028 water loss targets (maximum loss) are calculated from a State Water Resource Control Board created economic model (link to the create model version below) that incorporates both water loss and economic metrics.
  • The majority of the economic model’s inputs can be customized by supplier if documentation is submitted.  However not all inputs are weighted equally in the model.  Additional information on model inputs can be found below:


October 2022

Update provided by Amy Talbot, Chair of CA-NV AWWA Water Loss Committee

The State Water Board staff will present the SB 555/SB 606/AB 1668 Water Loss Regulation for Board approval at their October 19th Board meeting (starting at noon).  Please see the agenda (page 3, item #9), item details, and draft resolution for approval for more information. 

SWB staff will be posting an updated version of the regulation text soon, however, staff stated via email “there will be no substantive changes between the reg text that was posted on September 2nd and the one that will be published.”   In the meantime, the September 2nd regulation text (tab 3) and the September 9th supplier targets/standards (under water loss model, standards and questionnaires heading, which also includes the economic model) can be reviewed.  I will send the updated regulation text as soon as it is available.  It is unclear if the supplier targets will also be updated.  We do not anticipate any additional changes to the economic model.

Stakeholders are welcome to attend the October 19th Board meeting online or in person to provide comments.  More information on how to provide comments here

September 2022

The 2nd formal rulemaking for the water loss regulation started on Friday, September 2nd and will run through Monday, September 19th at noon PST.

Here is the official notice and revised regulation text.  An updated version of the economic model and supplier specific water loss standards has also been posted here (dated September 2nd). 

NOTE #1:  Please check your supplier standards as they may have changed, especially those systems that had an initial benefit cost ratio <1 as your standard has reverted back to current loss. 

Note #2:  It looks like at least some of the small systems between 200 and 3,000 connections are not listed in the updated standards spreadsheet.  An inquiry has been sent to State Water Board staff to figure out why they were left out.

Main changes in regulation text and model between the August 8th version and the September 2nd version include:

  • Changes to the definition of urban retail water supplier regarding small systems
  • Error corrections to the leak volume related model calculations (shouldn’t change supplier standards overall but will change Benefit Cost Ratio for some suppliers)
  • Changes to the “off ramp” option text (only available as an option for suppliers with loss 16 gallons per connection per day or less that also meet a bunch of data quality criteria)
  • Overinvestment was removed and replaced with long term cost effectiveness

Next Steps:

The water loss coalition (ACWA, CMUA, CA NV AWWA and CWA) are working on a draft comment letter based on the various meetings we’ve had over the last month or so.  More information on the draft letter to come soon!

If you are interested in submitting a comment letter by the September 19th at noon PST deadline:

  • Send email to [email protected]. The State Water Board requests but does not require that email transmission of comments, particularly those with attachments, contain the regulation package identifier “Comment

Letter – Proposed Water Loss Performance Standards” in the subject line to facilitate timely identification and review of the comment

  • Comments should be focused on the CHANGES made after the February 2022 regulation text and model versions.

January 2022

  • Formal rulemaking started Dec. 24th and comments are due to the SWRCB by Feb. 11th
  • If there are major changes an additional 15-day comment period will be added
  • Regulation is expected to be adopted in Q2

For more updates about major changes and next steps, please review these slides prepared by Amy Talbot at RWA for CA-NV AWWA Water Loss Committee on January 13, 2022.

November 2021

The Standardized Regulatory Impact Assessment (SRIA) Report was publicly posted on October 13, 2021.  The SRIA is a required economic analysis of the costs and benefits of implementing the water loss regulation.  The SRIA is developed by the State Water Board and submitted to the California Department of Finance.  There is no formal comment period on the document. However, suppliers can submit informal comments to State Water Board staff.  This is the first step to initiate the formal rulemaking process, which is expected to start on December 24, 2021.  See timeline below for more information about the formal rulemaking process.

August 2021

The updated economic model was released in April 2021. The SWRCB is encouraging water suppliers to customize the inputs and submit to SWRCB staff for approval an updated 2028 target. Formal rulemaking is expected to start in Fall 2021.

Economic model found here.

Timeline of Events

  • April 15 – Revised draft economic model and performance standards
  • Ongoing discussions:
    • CMUA Compliance Path – >30% reduction
    • Changes to economic model
    • Supplier option to customize economic model inputs
    • Recent addition of apparent loss target (only real loss target originally)
  • October 13, 2021 – Release of the Standardized Regulatory Impact Assessment (SRIA)Report -Required economic analysis of regulation implementation
    • No formal comment period, CA NV AWWA to submit informal comments on November 19, 2021
  • Mid December 2021– Public posting of formal rulemaking materials (including proposed water loss regulation text)
  • December 24, 2021 – Start of formal rulemaking process, initial 45-day comment period (can extend up to 365 days)
  • January 3rd-7th, 2022  –State Water Board to host public workshop to discuss additions and change to the proposed water loss regulation
  • January 5, 2022 – ACWA/CMUA Workgroup meeting to discuss proposed water loss regulation
    • Contact Chelsea Haines, ACWA, for more information
  • Late January/Early February 2022 – State Water Board to host public hearing for stakeholder comments on proposed water loss regulation
    • Comments can be submitted to the State Water Board via email anytime during the 45-day comment period
  • April/May 2022 – Anticipated Regulation approval
  • July 1, 2022 -  Effective date of approved Regulation
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