PFAS Drinking Water Regulations

A few different agencies are involved in drinking water regulations in California: California State Water Board Division of Drinking Water (DDW), US Environmental Protection Agency, and the Office of Environmental Health Hazard Assessment (OEHHA).

Maximum Contaminant Levels

In March 2023, the US EPA took a key step to protect public health by proposing national drinking water maximum contaminant levels (MCLs) for six PFAS known to occur in drinking water. This regulation would require public water systems to monitor for these PFAS, notify the public of the levels of these PFAS, and reduce the levels of these PFAS in drinking water if they exceed the proposed levels. The regulation has not yet been established but is expected to be finalized in the near future.



Notification and Response Levels

In September 2020, California State Water Board Division of Drinking Water (DDW) issued an order to certain systems (based on their proximity to potential sources of PFAS) to perform quarterly monitoring for four types of PFAS.

California State Water Board Division of Drinking Water also established tiers of advisory levels for certain PFAS:

• Notification Levels are health-based advisory levels at which, according to the California Health and Safety Code, do not pose a significant health risk based on available scientific information but warrant notification of governing bodies.
• Response Levels are action-based advisory levels, which require water systems to take one of the following actions:
• Take the source out of service
• Utilize treatment or blending
• Provide public notification.

Public Health Goals

In 2021, the Office of Environmental Health and Hazard Assessment released draft Public Health Goals (also known as PHGs) for two PFAS: PFOA and PFOS. These Public Health Goals are levels / concentration of drinking water contaminants that at stated levels or below pose no significant health risk, based on current risk assessment principles, practices, and methods.



Lifetime Health Advisory Levels

In June 2022, the US EPA released interim Lifetime Health Advisories (LHAs) for PFOA and PFOS. The interim health advisories will provide guidance to water systems for the period prior to the MCLs going into effect. In addition, they released final Lifetime Health Advisories for two other PFAS: perfluorobutane sulfonic acid (PFBS) and hexafluoropropylene oxide dimer acid and its ammonium salts (GenX). Similar to Public Health Goals, Lifetime Health Advisories identify the concentration of a contaminant in drinking water at which adverse health effects are not anticipated to occur over a lifetime.