PFAS information

What are PFAS?

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

There are thousands of different PFAS. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are two PFAS that have been well studied. Certain PFAS are no longer manufactured in the US. However, they may still be 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 industrial facilities using these chemicals. PFAS have been found in groundwater below industrial sites, particularly airports, firefighting/training sites, and landfills.

As of mid-2023, there are no enforcable standards for PFAS in drinking water in California. Regulations are in development, however. About half of all states and the EPA are beginning to regulate PFAS (individually and as a group). Some states have enforceable maximum levels, others have various types of advisories and monitoring requirements.

Water suppliers including EBMUD were required to sample for 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 specific 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 Water 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.

In California, AB 756 (effective Jan 1, 2020) authorized the State Water Board to require water systems to sample for PFAS. Monitoring is being done in phases, with high-risk systems starting first in accordance with specific Monitoring Orders from the State Water Board. Results are posted on DDW’s website. EBMUD has not yet been included in the Monitoring Orders under AB 756 except for the supplemental supply from the Sacramento River at Freeport.

In March 2023, EPA proposed new enforcable regulations and monitoring requirements for six PFAS. EPA expects to finalize these new regulations by the end of 2023. The six PFAS to be regulated are PFOA, PFOS, PFBS, PFNA, HFPO-DA, and PFHxS. 

EBMUD's drinking water sources are fairly well protected from human-made contaminants. The Mokelumne River watershed and Pardee Reservoir are located in the Sierra Nevada foothills, far from industrial contamination sources. Our local reservoirs, such as Upper San Leandro and San Pablo Reservoirs are also well protected, surrounded by sparsely populated watershed lands. Nonetheless, PFAS are widespread in the environment and they are detected at very low levels nearly everywhere.

EBMUD tested for PFOA and PFOS in 2013-2015 as required by EPA's Unregulated Contaminant Monitoring Rule 3 (UCMR3). The results were non-detect,

Analytical methods have improved since UCMR3, and detection levels today are lower. Based on prior sampling, and the protected nature of our watersheds, EBMUD is not required to sample under existing State Water Board Monitoring Orders because EBMUD’s system is not considered at risk.

Although not required, EBMUD sampled its source waters and treated waters in 2020 and 2021 for PFAS.

  • The most advanced analytical method available at the time of sampling was used (EPA method 537.1)
  • This method produces results for 18 different PFAS; however some of the PFAS included in EPA's 2023 draft regulations were not included.
  • EBMUD sampled quarterly from raw waters and WTP effluents

In this descretionary monitoring, all results (all locations and all parameters) were below the state's Notification Levels. Some low concentrations of some PFAS compounds were detected, including PFOA and PFOS. Some individual PFOA and PFOS results were slightly higher than the new enforceable standards proposed by EPA of 4 ppt (results varied from <1.8 ppt to 4.9 ppt).

EBMUD is currently sampling for a longer list of PFAS using two analytical methods, EPA method 537.1 and EPA method 533. This monitoring is requried by EPA under the UCMR5. Monitoring began in early 2023 and must be completed by 2025. All results from the first quarter of 2023 were lower than EPA's proposed regulatory standards and lower than California's Notification Levels, however there were some low-level detections of some PFAS.

EPA will release PFAS monitoring data from all water systems, including EBMUD, as it becomes available here.


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