Microplastics

As stated in Health and Safety Code section 116350 et seq., California Safe Drinking Water Act (Act) requires the State Water Resources Control Board (State Water Board) to administer provisions related to drinking water to protect public health. The Act allows the State Water Board to conduct research, studies, and demonstration programs to ensure provision of a dependable, safe supply of drinking water, which may include improving methods to identify and measure the existence of contaminants in drinking water and to identify the source of the contaminants. The Act also grants the State Water Board the authority to implement regulations that may include monitoring of contaminants, and requirements for notifying the public of the quality of the water delivered to customers.

On September 28, 2018, Senate Bill No. 1422 was filed with the Secretary of State , adding section 116376 to the Health and Safety Code, and requiring the State Water Board to adopt a definition of microplastics in drinking water on or before July 1, 2020, and on or before July 1, 2021, to adopt a standard methodology to be used in the testing of drinking water for microplastics and requirements for four years of testing and reporting of microplastics in drinking water, including public disclosure of those results.

Press Release: State Water Board addresses microplastics in drinking water to encourage public water system awareness (06/16/2020)

Proposed Action

Consistent with Health and Safety Code section 116376 and within its authority, the State Water Board is reviewing existing research and studies to accomplish the following tasks:

  • On or before July 1, 2020: Adopt a definition of microplastics in drinking water;
  • On or before July 1, 2021:
    • Adopt a standard methodology for testing of microplastics in drinking water;
    • Adopt requirements for four years of testing and reporting of microplastics in drinking water, including public disclosure of those results;
    • Consider issuing quantitative guidelines (e.g., notification level) to aid consumer interpretations of the testing results, if appropriate;
    • Accredit qualified laboratories in California to analyze microplastics in drinking water.

Health and Safety Code section 116376 allows the State Water Board to implement these tasks through the adoption of a Policy Handbook that is not subject to the Administrative Regulations and Rulemaking requirements of Government Code section 11340 et seq.

Definition of Microplastics in Drinking Water

On March 19, 2020, a proposed definition of 'microplastics in drinking water' to be considered for adoption by the State Water Board was made available, along with a draft Staff Report.

A proposed definition of 'microplastics in drinking water' prepared on February 1, 2020 was reviewed by an external panel of experts. The draft definition reviewed by the expert panel and their comments comments are available.

A public workshop detailing the proposed definition of 'microplastics in drinking water' was held at the State Water Board on April 8, 2020. The presentation was recorded and is available.

The proposed definition of 'microplastics in drinking water' was made available for public comment from March 24 - April 24, 2020. Details regarding the public comment period, notice of staff workshop, and hearing for Board adoption were made available on March 24, 2020.

State Water Board responses to comments on the March 19 proposed definition of 'microplastics in drinking water' were prepared and made publicly available on June 3, 2020 in document and table format. In response to public comments, a revised draft staff report was made available on June 3, 2020.

The State Water Board considered a resolution to adopt a proposed definition of 'microplastics in drinking water' at the June 16, 2020 Board Meeting (Notice). The final adopted resolution and definition was made available on July 27, 2020.

Health Effects of Microplastics

In coordination with the State Water Resources Control Board and the Ocean Protection Council, the Southern California Coastal Water Research Project, San Francisco Estuary Institute, and University of Toronto are hosting a Microplastics Health Effects Webinar Series. The series involves reviewing and assessing the available toxicological studies on microplastics, and convening an international group of experts to evaluate these studies and identify the primary pathways by which microplastics affect biota, prioritize microplastics characteristics (e.g., size, shape, polymer type) that are of greatest health concern, and identify critical thresholds for each at which those biological effects become pronounced. The findings from this webinar series will inform the potential development of a health-based guidance level for microplastics in drinking water, in accordance with Health and Safety Code section 116376.

The Microplastics Health Effects Webinar series is free and open to the public, and will take place as a series of five sessions from 8 a.m. to 10 a.m. (Pacific Time) every Monday from October 19 to November 16, 2020. Registration, agenda, speaker biographies, presentation recordings, and additional details may be found on the Southern California Coastal Water Research Project website.

Contact Information

Melissa Hall, P.E.
Senior Water Resource Control Engineer
(916) 323-0373
Melissa.Hall@waterboards.ca.gov

Scott Coffin, Ph.D.
Research Scientist III
(916) 323-0375
Scott.Coffin@waterboards.ca.gov