PFAS information

What are PFAS?

Per- and Polyfluoroalkyl Substances (PFAS) are synthetic compounds that are typically manufactured for their non-stick, heat-resistant, water and oil resistant properties. PFAS are everywhere, used in consumer products including cookware, carpets, clothes, furniture fabrics, food packaging, and fire-fighting foams. They degrade extremely slowly and remain persistent in the environment.

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are two PFAS. Certain PFAS chemicals are no longer manufactured in the US. However, they are still produced internationally and are imported into the US in consumer goods.

Most people have been exposed to these chemicals through consumer products, and virtually all Americans have detectable levels of PFAS in their blood. These chemicals have been widely used for decades in industrial applications and consumer products.

PFAS are not naturally occurring; when PFAS are spilled into to the environment they can seep into groundwater and stay there for many years and potentially travel great distances. PFAS have been found in surface water as a result of a release from an industrial facility using these chemicals. PFAS have been found in groundwater below industrial sites, particularly airports, firefighting/training sites, and landfills.

Water suppliers including EBMUD were required to sample PFAS from 2013 to 2015 to meet federal EPA requirements (Unregulated Contaminant Monitoring Rule 3). None were detected in EBMUD water under this monitoring effort.

In 2016 the EPA established a drinking water health advisory of 70 parts per trillion (ppt) for a combined concentration of PFOA and PFOS (A part per trillion is the equivalent of one grain of sand in an Olympic-size swimming pool). 

In 2019, California developed "notification levels" for two particular PFAS. PFOS has a notification of 6.5 ppt, and PFOA’s is 5.1 ppt. Exceeding the notification level would require notification of the State Board. In 2020, California adopted a "response level" of 10 ppt for PFOA and 40 ppt for PFOS. Exceeding the response level would require that the source be taken out of service or that formal, written public notification be made.

About half of all states and the EPA are beginning to regulate PFAS (individually and as a group). Some states have mandatory levels, others have various types of advisories.

AB 756 (effective Jan 1, 2020):  authorizes the State Water Resources Control Board Division of Drinking Water to require PFAS sampling, but DDW has not indicated low-risk systems like EBMUD’s will be part of early efforts. High-risk systems, vulnerable to PFAS contamination, have already begun monitoring under orders from the State Division of Drinking Water. Results are posted on DDW’s website.

EBMUD's primary drinking water sources are well protected. The Mokelumne River watershed and Pardee Reservoir are located in the Sierra Nevada foothills, far from industrial contamination sources. Our local reservoirs, such as Briones and San Pablo Reservoirs are also well protected, surrounded by watershed lands.

EBMUD tested for PFOA and PFOS in 2013-2015. The results were non-detect, although analytical methods have improved and detection levels today are lower. Based on prior sampling, and the protected nature of our watershed, EBMUD is not required under existing Division of Drinking Water regulations to sample because EBMUD’s system is not high-risk.

Although not required, EBMUD is sampling source water and treated water in 2020 and 2021.

  • EBMUD is using the most advanced analytical method available at the time of sampling (EPA method 537.1)
  • This method will quantify 18 different PFAS
  • EBMUD is sampling quarterly from raw waters and WTP effluents
  • Very precise and detailed testing protocols are needed to detect concentrations at ppt (parts per trillion) levels and avoid sample contamination

In 2020, all results (all locations and all parameters) were below the state's Notification Levels. Some low concentrations of some PFAS compounds were detected. Additional sampling is being done during 2021.


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