Regulating Direct Potable Reuse in California

The State Water Board’s Division of Drinking Water (DDW) is carrying out a series of legislative mandates regarding Direct Potable Reuse (DPR). DPR is the planned introduction of recycled water either directly into a public drinking water system, or into a raw water supply immediately upstream of a drinking water treatment plant.

The State Water Board’s DDW, formerly the California Department of Public Health’s Drinking Water Program, investigated the feasibility of developing uniform water recycling criteria for DPR, as mandated by SB 918 and SB 322. The State Water Board completed the investigation in December 2016 and submitted a report to the Legislature with its findings and recommendations. Please see the State Water Board’s DPR Feasibility webpage for more information on that effort.

In 2017, the State Water Board’s DDW was tasked with developing uniform water recycling criteria for DPR that is protective of public health. AB 574 (Water Code, Division 7, Chapter 7.3) requires the State Water Board to adopt uniform water recycling criteria for DPR through raw water augmentation on or before December 31, 2023. Among other things, AB 574 requires that the State Water Board:

  • Develop DPR criteria using information from the DPR research recommended in the State Water Board’s Report to the Legislature, after soliciting stakeholder input.
  • Establish and administer an expert review panel to review the proposed criteria and make a finding as to whether, in its expert opinion, the proposed criteria would adequately protect public health.

Status

  • The State Water Board developed “A Framework for Regulating Direct Potable Reuse in California” as recommended by AB 574, and solicited feedback from stakeholders and the public in a series of public meetings, public comment periods, and board meetings in 2018 and 2019.
  • The State Water Board is addressing key research and knowledge gaps discussed in the State Water Board’s Report to the Legislature.
  • The State Water Board plans to convene an expert review panel in 2021.

 

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 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.

Commenters Submitted by

California Coastkeeper Alliance

Sean Bothwell

Valley Water

Norma Camacho

Metropolitan Water District

Mickey Chaudhuri

Irvine Ranch Water District

Paul Cook

Inland Empire Utilities Agency

Shivaji Deshmukh

City of San Diego

Amy Dorman

Santa Margarita Water District

Daniel Ferons

San Diego County Water Authority

Kelley Gage

Friends of the North Fork (American River)

Michael Garabedian

Carollo Engineers

Andrew Salveson

General Public

Laura Santiesteban

Los Angeles Department of Water & Power

Mark Sedlacek

Association of California Water Agencies

Melissa Sparks-Kranz

WateReuse California

Jennifer West

City of Los Angeles Sanitation and Environment

Enrique Zaldivar

Main San Gabriel Basin Watermaster

Anthony Zampiello

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.

Commenters Submitted by

Russian River Watershed Protection Committee

Brenda Adelman

Irvine Ranch Water District

Paul Cook

City of San Diego

John Helminski

General Public

Dr. Edo McGowan

San Diego County Water Authority

Toby Roy

Metropolitan Water District

Mic Stewart

Water Plus

Ron Weitzman

WateReuse California
California Association of Sanitation Agencies
California Coastkeeper Alliance

Jennifer West
Roberta Larson
Sean Bothwell

Separation Processes, Inc.

James Vickers

California Municipal Utilities Association

Jonathan Young

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 (TWRF) to provide scope and direction, provide technical review, and oversee the completion of five research projects by scientific and technical experts convened by TWRF. 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.

TWRF project website for DPR-1

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.

TWRF 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.

TWRF 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.

TWRF 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.

TWRF project website for DPR-5

TWRF Presentations at Conferences and Webcasts

TWRF 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, TWRF 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.

 

DPR Criteria Expert Panel

Before the State Water Board can adopt uniform water recycling criteria for DPR raw water augmentation, an expert panel must review the proposed criteria and make a finding as to whether, in its expert opinion, the proposed criteria would adequately protect public health (Water Code section 13561.2).

If the State Water Board finds that it is not able to adopt uniform water recycling criteria for DPR due to insufficient information from the DPR research conducted, the State Water Board must consult with the expert panel regarding the research and the need for additional scientific and technical research necessary for the State Water Board to complete the criteria, including the estimated time frame needed to conduct the additional research.   

The State Water Board DDW plans to convene the expert panel in 2021.

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Contact Us

Randy Barnard, P.E.
Senior Sanitary Engineer
Chief, Recycled Water Unit
(619) 525-4022
E-mail questions to DDWrecycledwater@waterboards.ca.gov

  (Page last updated 10/09/2020)

 
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