California Requirements for Microplastics In Drinking Water

The California State Water Resources Control Board (SWRCB) Division of Drinking (DDW) posted information that they anticipate holding a Board workshop in late summer 2021 on “….standardized methodology, sampling & analysis plan, health effects, and accreditation…” for microplastics in drinking water.  During fall 2021, DDW anticipates going to the Board to propose adoption of these requirements.


In 2018 California adopted a law (Senate Bill 1422, adding section 116376 to the Health and Safety Code) that required DDW adopt a definition of microplastics in drinking water before July 1, 2020.

On March 24, 2020 the SWRCB DDW published for a 30-day public comment period a proposed definition of microplastics in drinking water.  A final definition of microplastics in drinking water was adopted by the SWRCB on June 16, 2020.

The 2018 law required that by July 1, 2021 the SWRCB adopt test methodology for microplastics in drinking water, adopt requirements for four years of testing and reporting on microplastics in drinking water, and develop accreditation requirements for laboratories to analyze microplastics.

The law also indicated that DDW, if appropriate: “….consider issuing a notification level or other guidance to aid consumer interpretations of the results of the testing required pursuant to this section.”