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Source: https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/onsite_nonpotable_reuse_regulations.html

Onsite Treatment and Reuse of Nonpotable Water

Status of the Regulations

Rulemaking is completed. The regulations are effective as of April 22, 2026.

Overview

California Water Code section 13558 requires the State Water Board to adopt regulations on or before December 1, 2022, for risk-based water quality standards for the onsite treatment and reuse of nonpotable water for nonpotable end uses in multifamily residential, commercial, and mixed-use buildings. Water Code section 13558 also requires that on or before December 1, 2023, the Department of Housing and Community Development, in consultation with the State Water Board, is required to develop and propose for adoption any necessary corresponding building standards to support the risk-based water quality standards established by the State Water Board. Pursuant to Water Code subsections 13558(c) and (d), the risk-based water quality standards will not address untreated graywater systems that are used exclusively for subsurface irrigation and untreated rainwater systems that are used exclusively for surface, subsurface, or drip irrigation. Existing onsite treated nonpotable water systems in operation before the effective date of the regulations will be required to comply with the regulations within two years of the effective date.

Update to the Proposed Pathogen Control Treatment Trains

The following slides are prepared by State Water Board DDW staff to address requests from stakeholders to provide an update to the draft requirements related to the proposed pathogen control treatment trains initially presented in the August 1, 2022, staff workshop. Please note that the information provided on these slides are not considered regulations. Formal rulemaking for these regulations will commence in 2024 as described in the Status of Regulations above. * Updated LRT and treatment train slides

Staff Workshop

A staff workshop for the regulations was held on August 1, 2022. Staff workshop information along with the video recording and presentation slides are available in the links below: * Notice of Staff Workshop * How to attend the virtual staff workshop * Agenda * Video Recording * Presentation slides

Frequently Asked Questions

State Water Board DDW staff has developed a set of frequently asked questions regarding the regulations. For any questions not addressed in the document, please contact ddwrecycledwater@waterboards.ca.gov * Frequently Asked Questions

Rulemaking Information

Visit the Regulations for Onsite Treatment and Reuse of Nonpotable Water (SBDDW-22-001) page.

Subscribe to Mailing List

Subscribe to our Drinking Water Onsite Non-potable Reuse email list to receive notifications and the latest updates. After subscribing, you will need to check your email host for a confirmation email to complete the subscription. Email Address

Contacts

For Questions or Comments, please contact: * Sherly Rosilela
Senior Water Resource Control Engineer
(916) 341-5578
Sherly.Rosilela@waterboards.ca.gov * Report an Environmental Concern

Resources

(Page last updated 04/23/2026)

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