Regulating Direct Potable Reuse in California

About the Framework

The State Water Board DDW staff has prepared the Framework which  satisfies the recommendation in Assembly Bill (AB) 574 (Chapter 528, Statutes of 2017) to establish a framework for the regulation of potable reuse projects. In preparing the Framework, the State Water Board included the following elements stated in the California Water Code section 13560.5:

1. The consideration of recommendations provided in the State Water Board’s “Investigation on the Feasibility of Developing Uniform Water Recycling Criteria for Direct Potable Reuse.”
2. A schedule for completing the recommended research described in “Investigation on the Feasibility of Developing Uniform Water Recycling Criteria for Direct Potable Reuse.”
3. A regulatory framework for potable reuse projects that will be protective of public health.
4. A process and timeline for updating uniform water recycling criteria for potable reuse through reservoir water augmentation.

The Framework is intended to primarily document and communicate the State Water Board Division of Drinking Water’s (DDW) current thinking on regulating direct potable reuse in California. The feedback received from the public will help inform the State Water Board in laying the groundwork for the development of the uniform water recycling criteria for direct potable reuse. The Framework is not a regulatory document. A rulemaking process pursuant to the Administrative Procedure Act will be a separate effort undertaken by the State Water Board for the uniform water recycling criteria for direct potable reuse through raw water augmentation.

Framework Addendum – March 2021

The State Water Board DDW staff has prepared an Addendum to the Framework, which consists of an early draft of the anticipated criteria for direct potable reuse that was developed using information from the recommended DPR research as required by section 13561.2 of the Water Code. The State Water Board is seeking public comment, and soliciting stakeholder input from water agencies, wastewater agencies, local public health officers, environmental organizations, environmental justice organizations, public health nongovernmental organizations, and the business community as required by section 13561.2(a)(1).

  Download the Framework Addendum (PDF)

Public Comments

State Water Board staff is seeking feedback from the public and interested parties on the addendum to the Framework (Framework Addendum). Written public comments will be accepted during the public comment period. DDW staff will review all comments received but may not be able to provide an individualized detailed response. The State Water Board will provide an opportunity for the public to present oral comments at a public workshop. Information on the workshop will be provided in a separate notice.

Public Comment Period

22 March 2021 – 25 June 2021

DDW staff received a total of 21 comment letters by June 25, 2021. To request electronic copies of the comment letters, please send an email to DDWrecycledwater@waterboards.ca.gov.

  Download the Notice of Public Comment Period (PDF)

Staff Workshop

State Water Board DDW staff held an online public workshop in April 2021 to provide an opportunity for the public to present oral comments on the Addendum.

Download the Workshop Notice (PDF).

Recorded video of the Workshop (presentations start at the 00:03:40 minute mark, public comments start at the 1:10:00 minute mark).

Framework Second Edition – August 2019

The State Water Board DDW staff has completed a revision to the Framework (Framework Second Edition) to reflect the Board’s current thinking on regulating direct potable reuse. The Framework Second Edition includes a discussion of the regulatory approach for direct potable reuse, as well as an update on the consideration of drinking water treatment plants. The Framework Second Edition is presented in a format that highlights the revisions that were made. Content that have been added are indicated by underlining the new text, and content that have been deleted are indicated by a strikethrough, which is a line drawn through the text.

  Download the Framework Second Edition (PDF)

Public Comments

The State Water Board released the Framework for a 30-day public comment period in September 2019 (September 3, 2019 – October 9, 2019).

Public Comment Period
3 September 2019 – 9 October 2019

  Download the Notice of Public Comment Period (PDF)

DDW staff received a total of 16 comment letters by the end of the day on October 9, 2019. To request electronic copies of the comment letters, please send an email to DDWrecycledwater@waterboards.ca.gov.

Board Meeting

State Water Board DDW staff presented the Framework as an informational item at the State Water Board hearing on November 5, 2019. A link to the recorded video of the Board presentation is available below.
Recorded Video of the Board Item (starting at the 0:36:00 minute mark)

Framework – April 2018

The State Water Board DDW staff completed the Framework in April 2018. Completion of the Framework satisfied the recommendation of AB 574 to establish a framework for the regulation of potable reuse projects on or before June 1, 2018.
The Framework and Fact Sheet can be downloaded from web links below.

  Download the Framework (PDF)

  Download the Fact Sheet (PDF)

Board Workshop

State Water Board DDW staff held workshops in Northern California and Southern California to present the Framework in April 2018.

  Download the Workshop Notice (PDF)

Public Comments

The State Water Board released the Framework for a 30-day public comment period in April 2018 (April 19, 2018 – May 20, 2018).

DDW staff received a total of 10 comment letters by the end of the day on May 20, 2018. To request electronic copies of the comment letters, please send an email to DDWrecycledwater@waterboards.ca.gov.

Board Meeting

State Water Board DDW staff presented the Framework as an informational item at the State Water Board hearing on June 5, 2018. A link to the recorded video of the Board presentation are available below.

Recorded Video of the Board Item (starting at the 2:54:00 minute mark)

Enhanced Source Control Expert Panel

In its Report to Legislature on the Feasibility of Developing Uniform Water Recycling Criteria for DPR, the State Water Board determined through its investigation that key knowledge gaps and research recommendations must be addressed before uniform water recycling criteria for DPR can be adopted. The State Water Board also identified improvements needed to enhance the safety of DPR, including enhanced industrial source control to address chemicals of concern that may be released into domestic wastewater and treatment optimization related to DPR.

The National Water Research Institute (NWRI) convened a panel of experts to provide recommendations on enhanced industrial source control for DPR. The Expert Panel has submitted their recommendations to the State Water Board in their report. A copy of the report is available below.

Enhanced Source Control Expert Panel Final Report

Research to Support Criteria Development for Direct Potable Reuse

The State Water Board is coordinating with the Water Research Foundation (WRF) to provide scope and direction, provide technical review, and oversee the completion of five research projects by scientific and technical experts convened by WRF. Completion of the research is expected by March 2021. Funding is provided by Proposition 1.

DPR-1 Probabilistic Quantitative Microbial Risk Assessment (QMRA)

This research project is to conduct a literature review on QMRA, develop a QMRA tool, and develop a guidance document on how to evaluate data inputs and assumptions, how to review and evaluate QMRA assumptions and their outputs, and how to use the QMRA tool. The State Water Board DDW will consider probabilistic QMRA to assist in developing required pathogen log removal values as part of criteria development for DPR. The QMRA tool is anticipated to enable assessment of the performance of DPR treatment trains, provide an opportunity to identify additional effective DPR treatment trains, and contribute to the development of DPR criteria that further ensure that public health protection is paramount in DPR projects. Building a robust library of treatment plant performance data for a probabilistic assessment of treatment plant performance would be a benefit to further use of the QMRA tool.

WRF project website for DPR-1

The QRMA tool, DPRisk, is a Shiny web-based application, available at cawaterdatadive.shinyapps.io/DPRisk.

DPR-2 Conduct Pathogen Monitoring of Wastewater

This research project is to conduct pathogen monitoring in wastewater in order to gather more information on their concentrations and variability, and to provide additional pathogen data for the QMRA and other evaluations. The research project includes a literature review of previous pathogen monitoring studies and analytical methods used, an evaluation of the pathogens that are appropriate for monitoring, and identification of analytical methods that could be used. The research team developed a quality assurance project plan that describes the sampling plan for five participating wastewater treatment plants, describes analytical method optimization, and provides the analytical method standard operating procedures (SOPs) based on the method optimization work for wastewater matrices. The sampling campaign began in October 2019 and will continue through January 2021. In March 2020, the State Water Board DDW approved expanded sampling to include SARS-CoV-2, the virus responsible for COVID-19. The research team updated the SOPs for processing and enumerating viruses in wastewater to add procedures for SARS-CoV-2.

WRF project website for DPR-2

DPR-3 Feasibility of Collecting Pathogen Data in Wastewater During Outbreaks of Disease

This research is to investigate the feasibility of collecting raw wastewater pathogen concentration data associated with community outbreaks of disease. This research is important because pathogen concentrations in wastewater may increase significantly during disease outbreaks in the community, and the QMRA and other public health-focused evaluations must consider the full range of pathogen concentrations possible in wastewater, in order to accurately characterize the infection risk and ensure sufficient advanced water treatment is provided to protect public health. This research includes a literature review of disease outbreak monitoring and surveillance programs. The research team will investigate possible metrics that could be used to indicate outbreaks of disease, recommend what partnerships should be established or reinforced for DPR, what communications protocols are needed, and what pathogen monitoring plans could look like, in order to capture peak pathogen concentration data during outbreaks of disease.

WRF project website for DPR-3

DPR-4 Addressing Chemical Peaks in DPR

This research will identify suitable options for additional treatment processes that can provide some “averaging” with respect to potential chemical peaks, that is, rapid, short-lived increases in concentration, particularly for chemical contaminants that have the potential to persist through advanced water treatment. The research includes a literature review on the types and frequency of chemical peaks observed, characterization of chemical peaks (sizes and shapes of chemical peaks), and options for treatment. The research also includes small study to better understand whether online total organic carbon analyzers can detect the types of chemical peaks that persist through advanced water treatment.

WRF project website for DPR-4

DPR-5 Non-Target Analysis

This research is to evaluate potential analytical methods that can be used to assess unknown chemical contaminants, such as non-targeted analysis (NTA), to identify contaminants not presently detected by current monitoring approaches, particularly low molecular weight compounds that may occur in wastewater and may not be removed by advanced water treatment. The limited DPR-5 budget only allowed for completion of a White Paper that describes several analytical methods that may be applicable to NTA to address the knowledge gap in assessment of unknown chemical contaminants. In addition, the White Paper proposed a $1.2 million, five-year research plan to fully evaluate the analytical methods. The plan would include completing the scope of the research by evaluating the methods described in the White Paper, identifying the most appropriate methods for analysis of non-targeted low molecular weight compounds, developing standard operating procedures (SOP) for those methods, including quality assurance/quality control provisions, and validating the methods with a broad spectrum of commercial and municipal laboratories.

The DPR Feasibility Report to the Legislature indicates that the recommended research, including DPR-5, "must be addressed in order to be able to successfully adopt a set of uniform water recycling criteria for DPR." However, the State Water Board is also statutorily mandated on or before December 31, 2023, to adopt uniform water recycling criteria for direct potable reuse through raw water augmentation. State Water Board DDW is confident that this statutory deadline can be achieved through conservative regulatory requirements that minimize the potential health risks associated with low molecular weight compounds while concurrently pursuing funding and completion of the next phase of the research.

WRF project website for DPR-5

WRF Presentations at Conferences and Webcasts

WRF has held panel discussions with the DPR research teams at the WateReuse California annual spring conferences and at WateReuse annual fall symposiums over the last three years, which were held throughout the state (Monterey, Garden Grove, San Diego, and virtually in 2020). Additionally, WRF and the DPR research teams participated in two webcasts held to provide updates on the DPR research projects. Links to the presentation slides for these webcasts are provided below.

• June 12, 2020 WRF DPR Virtual Research Workshop – presentation slides
• November 7, 2019 Water Environment Federation Webcast - Research to Ensure Sound Potable Reuse Regulations: CA Water Board Partners with The Water Research Foundation

Expert Panel Meetings

Panel Meeting 4 – February 28, 2022 – Remote/virtual meeting

• Agenda
• Video Recording
• Presentation slides
  • NWRI, Expert Panel presentation
  • DDW staff presentation

Panel Meeting 3 – January 26, 2022 – Remote/virtual meeting

• Agenda
• Video Recording
• Presentation slides
  • NWRI, Expert Panel presentation

Panel Meeting 2 – December 1, 2021 – Remote/virtual meeting

• Agenda
• Report of Panel Proceedings
• Video recording
• Presentation slides:
  • NWRI, Expert Panel presentation
  • DDW staff presentation

Panel Meeting 1 – August 24 – 25, 2021 – Remote/virtual meeting

• Agenda
• Video recording of Day 1 of the meeting
• Video recording of Day 2 of the meeting
• Draft DPR criteria submitted to the Expert Panel, Addendum version 8-17-2021
• Report of Panel Proceedings
• Presentation slides
  • NWRI Introduction - Expert Panel Co-Chairs Welcome - DPR Feasibility Overview
    Kevin Hardy, NWRI, James Crook, Engineering Consultant, and Adam Olivieri, EOA, Inc.
  • DPR Statutory Mandate and Regulation Development - Drinking Water Statutes, Regulations and Permits - DPR Criteria Overview
    Randy Barnard, DDW, Kurt Souza, DDW, and Jing Chao, DDW
  • WRF Research Projects and Findings Briefing: Pathogen Monitoring and Plant Reliability QMRA (DPR-1 and DPR-2)
    Brian Pecson, Trussell Technologies
  • DPR Pathogen Control Criteria
    Robert Hultquist, DDW, and Saeedreza Hafeznezami, DDW
  • NWRI Day 2 Introduction
    Kevin Hardy, NWRI
  • WRF Research Projects and Findings Briefing: Defining Chemical Peaks and Management Options (DPR-4)
    Jean Debroux, Kennedy Jenks, and Shane Trussell, Trussell Technologies
  • DPR Chemical Control Criteria
    Brian Bernados, DDW

AB 574 requires the State Water Board to convene an expert review panel to review the proposed criteria for Direct Potable Reuse and make a finding as to whether, in its expert opinion, the proposed criteria would adequately protect public health.
The State Water Board provided a copy of the proposed draft criteria for DPR to the expert review panel in August 2021. The panel has completed review of the proposed draft and has prepared a draft memo on its preliminary findings, recommendations, and comments on the proposed draft criteria.

• Draft Memo on Expert Panel Preliminary Findings, Recommendations, and Comments on Draft DPR Criteria
• Appendix 4
• Appendix 5
• Appendix 6

The State Water Board has reviewed the panel’s draft memo and provided feedback to the panel. The DDW response to panel comments and recommendations includes proposed draft language.

• DDW Response and Feedback on the Draft Memo

The Expert Panel has submitted the final memo on Expert Panel Preliminary Findings and Recommendations on Draft DPR Criteria. The panel found that “the Early Draft of Anticipated Criteria for Direct Potable Reuse dated August 17, 2021, adequately protects public health.”

• Expert Panel Preliminary Findings and Recommendations on Draft DPR Criteria

The State Water Board has received several requests from stakeholders to provide an early copy of the draft criteria ahead of publication of the Notice of Proposed Rulemaking in the California Notice Register, which starts the formal 45-day public comment period under the Administrative Procedure Act. The State Water Board is posting an advance copy of the draft that has been submitted to the Office of Administrative Law.

PLEASE NOTE:
• Do not submit comments to the State Water Board on the advance copy - all comments submitted before the start of the formal 45-day public comment period will not be considered by the State Water Board.
• Revisions could be made to the advance copy, and therefore, the proposed DPR regulations that will be posted for the 45-day public comment period under the Administrative Procedure Act may be different than the advance copy. Stakeholders are cautioned to obtain the official version of the proposed regulations once the Notice of Proposed Rulemaking is published.
• The State Water Board expects that the Notice of Proposed Rulemaking will be published in the California Notice Register on July 21, 2023. The State Water Board will email the notices to subscribers of the “Recycled Surface Water Augmentation & Direct Potable Reuse” email list. Please click on the “Subscribe to Mailing List” (top of page, right side) to subscribe to the mailing list, so you can receive the email notice from the State Water Board.

Please obtain the draft regulation text for public comment on the DPR Regulation webpage .