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California Lowers Response Levels for PFOA and PFOS

Updated: Jul 27, 2020


Logo for the California Water Resources Control Board

On February 6, 2020, the California Water Resources Control Board (WRCB) announced it was lowering the response levels (RLs) for perflourooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) to 10 and 40 ng/L, respectively. The prior RLs for water providers were 70 ng/L for the combined concentration of the two compounds.


These new RLs are in response to requirements in Assembly Bill 756, which became effective on January 1, 2020. If test results exceed a RL, the water provider must:

  • Take the source out of service immediately,

  • Utilize treatment or blending to reduce the concentrations, or

  • Provide public notification of the exceedance within 30 days of receipt of the test results.

Table portraing the notification levels - PFOA notificaiton level 5.1 and response level 10 - PFOS notification level 6.5 and response level 40

Notes/comments: Notification levels (NL) are nonregulatory, health-based advisory levels.

Response levels (RL) are levels at which water systems consider taking a water source out of service or provide treatment.


These recent RLs changes follow the WRCB’s August 2019 decision to lower the notification levels (NLs) for PFOA to 5.1ng/L and for PFOS to 6.5 ng/L. An NL exceedance requires water provider to notify their governing boards and the WRCB within 30 days of receiving the test results.


The WRCB also asked the Office of Environmental Health Hazard Assessment (OEHHA) to proceed with the development of public health goals for both PFOA and PFOS. This is the first step in establishing maximum contaminants levels for these compounds. Finally, OEHHA was asked to develop NLs for seven additional per- and poly-fluoroalkyl substances (PFAS).


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