Recycled Water in California

Recycled water is defined in the California Water Code as “water which, as a result of treatment of waste, is suitable for a direct beneficial use or a controlled use that would not otherwise occur and is therefore considered a valuable resource.” Recycled water is typically domestic, municipal wastewater treated to safe standards for nonpotable or potable applications. Recycled water is categorized by its treatment level and expected use.

Nonpotable and Indirect Potable Reuse
Most commonly, California communities use recycled water for nonpotable uses like irrigation, industrial, and commercial uses. Indirect Potable Reuse (IPR) is the planned use of recycled water to replenish drinking water supplies with a suitable environmental barrier. Through advanced treatment, many communities are increasingly using recycled water for potable applications to replenish groundwater supplies and augment surface water reservoirs. For information on permitting for nonpotable and IPR projects, please see "Obtain a recycled water permit" below.

Direct Potable Reuse (DPR)
Direct Potable Reuse (DPR) is when highly treated recycled water is placed directly into a public water system or into a “raw” water supply immediately upstream of a drinking water treatment plant. The State Water Board’s DPR regulations went into effect on October 1, 2024. Prior to being allowed to engage in DPR, a public water system must first obtain a permit from the State Water Board’s Division of Drinking Water. Additional permit(s) may also be needed from the local regional water quality control board for the discharge of any off-spec water or reverse osmosis concentrate. For information on permitting for Direct Potable Reuse projects, visit State Water Board’s Division of Drinking Water page for Direct Potable Reuse.

Onsite Treated Nonpotable Reuse
The State Water Board continues working to develop regulations for onsite treatment and reuse of nonpotable water. Onsite treated nonpotable water systems will be permitted by local jurisdictions (city or county, or city and county). For information on the status of the regulations, visit the State Water Board’s Division of Drinking Water page for Onsite Treatment and Reuse of Nonpotable Water.

The production, distribution, and use of recycled water may be permitted through general or individual waste discharge requirements (WDRs) (CWC §13263), water reclamation requirements (WRRs) (CWC §13523), a master reclamation permit (MRP) (CWC §13523.1), or amendments to an adopted order, such as an existing WDR or National Pollutant Discharge Elimination System Permit. All appropriate and eligible proposed nonpotable recycled water proponents with the capability of taking on the responsibility of administrating water recycling programs must enroll under the statewide general Water Reclamation Requirements for Recycled Water Use (Order No. WQ 2016-0068-DDW) to provide permit coverage to distribute and/or use recycled water.

The nine Regional Water Quality Control Boards (regional water boards) issue these permits. In rare cases, such as where a proposed project falls under the jurisdiction of multiple regional water boards, the State Water Board may issue recycled water permits.

The regional water boards coordinate with the State Water Board’s Division of Drinking Water to ensure a proposed recycled water project complies with all federal and state regulations for the protection of public health. To recycle water, a project will need to demonstrate compliance with California Code of Regulations, title 22. This includes preparing an engineering report to describe the treatment process, intended end uses, and additional safety measures.

Recycled water projects must also complete a checklist to assist the State Water Board’s Division of Water Rights in evaluating whether a wastewater change petition will be necessary prior to implementing a recycled water project: Water Code Section 1211- Wastewater Change Petition Checklist.

To begin the recycled water permitting process please contact the appropriate Regional Water Board and the Division of Drinking Water’s Recycled Water Unit: ddw-recycledwater@waterboards.ca.gov.

The Water Boards encourage and regulate the safe use of recycled water in California through the following policies and regulations.

Recycled Water Policy
The Water Quality Control Policy for Recycled Water (Recycled Water Policy) encourages the safe use of recycled water from wastewater sources that meets the definition in California Water Code (Water Code) section 13050(n), in a manner that implements state and federal water quality laws and protects public health and the environment. The Recycled Water Policy provides direction to the regional water boards, proponents of recycled water projects, and the public regarding the methodology and appropriate water quality control criteria for the State Water Board and the regional water boards to use when issuing permits for recycled water projects. For more information, visit the State Water Board’s Division of Water Quality page for the Recycled Water Policy.

Recycled Water Regulations
The Uniform Statewide Recycling Criteria are contained in the California Code of Regulations, Title 22, Division 4, Chapter 3. The Uniform Statewide Recycling Criteria address each type of recycled water use where the use involves the protection of public health. A portion of the Indirect Potable Reuse: Surface Water Augmentation regulations are contained in California Code of Regulations, Title 22, Division 4, Chapter 17, Article 9. In addition to the Uniform Statewide Recycling Criteria, cross-connection control regulations address the protection of public water supplies from cross-connection with nonpotable systems and are contained in California Code of Regulations, Title 17, Subchapter 1, Group 4. The California Office of Administrative Law approved the proposed Direct Potable Reuse regulations and filed the regulations with the Secretary of State. The regulations went into effect on October 1, 2024. Regulations for onsite treated nonpotable reuse are in development. More information can be found at the following Division of Drinking Water pages:

• Nonpotable Reuse
• Indirect Potable Reuse
• Direct Potable Reuse
• Onsite Potable Reuse

The Water Boards require wastewater and recycled water dischargers (including dischargers that do not produce any recycled water) to annually report monthly volumes of influent, wastewater produced, and effluent, including treatment level and discharge type through the Volumetric Annual Report.

The link below allows you to access reports and statistics from data collected by wastewater and recycled water treatment facilities in the Volumetric Annual Report to view trends in recycled water, treatment capacities, and usage by region or category. Use the interactive tool or review the data from the open data portal to explore recycled water impacts and potential in California.

• Volumetric Annual Report of Wastewater and Recycled Water

Recycled water research continues to advance understanding and innovation of recycled water treatment methods, technologies, and applications. The State Water Board works with members of the recycled water community to identify knowledge gaps in recycled water research areas, for both potable and nonpotable applications. Staff uses this input to develop recycled water research funding priorities. The State Water Board has been a national leader for funding recycled water research across various topics through the Recycled Water Research Program. Additional information on this program and links to State Water Board-funded recycled water research can be found below:

• Recycled Water Research Program

The State Water Board Water Recycling Funding Program (WRFP) provides funding for construction loans and grants and planning grants. The mission of the WRFP is to promote the beneficial use of treated municipal wastewater (water recycling) to augment fresh water supplies in California by providing technical and financial assistance to agencies and other stakeholders in support of water recycling projects and research. For information on how to apply for funding through this program, visit the State Water Board’s Division of Financial Assistance page for the Water Recycling Funding Program.

The Water Supply Strategy directed the State Water Board to work with local water and sanitation agencies to identify recycled water projects that hold the potential to be operational by 2030 and by no later than 2040. To respond to this directive, State Water Board staff compiled a list of planned recycled water projects in coordination with WateReuse California and California Association of Sanitation Agencies, and with input from recycled water and wastewater agencies, regional water boards, and data from the Volumetric Annual Report.

• Planned Recycled Water Projects

The list is a 2023 snapshot of planned projects that anticipate additional recycled water production. State Water Board staff will continue tracking recycled water production on an annual basis through the Volumetric Annual Report to evaluate progress towards the recycled water goals.

Per the Water Supply Strategy, the State Water Board has convened a Recycled Water Strike Team (Strike Team) to support planned recycled water projects by assisting to resolve permitting and funding obstacles. The Strike Team's objectives are to communicate with project proponents on permitting and funding barriers to implementation; and to then facilitate discussion and recommend solutions to address those barriers. To request assistance from the Strike Team, project proponents may contact: recycledwater@waterboards.ca.gov.