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Per - and Polyfluoroalkyl Substances (PFAS)

Per- and Polyfluoroalkyl Substances (PFAS)

Per- and polyfluoroalkyl substances (PFAS) are a group of thousands of different chemicals that have been manufactured and used in a variety of commercial products since the 1940s – from everyday household items to food packaging – due to their heat, moisture, stain resistance, and non-stick qualities.  PFOS and PFOA have been the most extensively produced and studied of these chemicals, followed by PFHxS and PFNA.  These chemicals do not break down in the environment or human body and can accumulate over time.  There is evidence that exposure to certain PFAS can lead to adverse human health effects.  For more information, see the OHA Environmental Public Health PFAS webpage

PFAS Drinking Water Health Advisory Levels

Oregon Drinking Water Health Advisories for PFAS

OHA has established drinking water health advisory levels (HALs) for four PFAS compounds most commonly found in humans.  These health advisory levels for PFOS, PFOA, PFNA, and PFHxS are based on adverse developmental and immune effects and are set at levels meant to protect all persons, including sensitive populations, from both short- and long-term exposures in drinking water.

Oregon Drinking Water Health Advisory Levels (HALs)*
parts per trillion (ppt) or nanograms per liter (ng/L)
30 ppt
30 ppt
30 ppt
30 ppt

*Because these chemicals may have cumulative health effects, OHA will also calculate the sum of detections of the four PFAS chemicals with HALs in the table above. The HAL is exceeded when any of these four PFAS chemicals with results showing detections exceeds 30 ppt, or when the sum of these four PFAS chemicals with results showing detections exceeds 30 ppt. PFAS chemicals with a HAL that are not detected and other PFAS chemicals that do not have a HAL would not be included in the calculation.

Oregon’s drinking water PFAS HALs are non-regulatory and do not mandate a required action; rather they provide information on health risks of certain PFAS compounds so that drinking water system operators and health officials can take the appropriate steps to protect drinking water consumers. OHA's expectation is that public water systems will notify their customers if a health advisory level is exceeded.

EPA Drinking Water Health Advisories for PFAS

EPA has developed drinking water health advisory levels (HALs) for four PFAS chemicals: PFOA (0.004 ppt), PFOS (0.02 ppt), GenX Chemicals (10 ppt), and PFBS (2000 ppt). EPA's HALs are non-enforceable and non-regulatory. When results show the presence of PFAS in drinking water above an EPA HAL, EPA recommends public water systems take steps to assess contamination, inform customers, and limit exposure. For more information on recommended PWS actions for drinking water PFAS results above the EPA HALs, please refer to EPA’s “Drinking Water HAs for PFAS Fact Sheet for Public Water Systems”:
. More information about the EPA HALs can be found on EPA’s website here:

PFAS Monitoring by Public Water Systems in Oregon

Third Unregulated Contaminant Monitoring Rule (UCMR3)

Six PFAS compounds (PFOS, PFOA, PFNA, PFHxS, PFHpA, and PFBS ) were among the list of contaminants that public water systems were required to monitor for under the third Unregulated Contaminant Monitoring Rule (UCMR3). All public water systems nationwide serving more than 10,000 people and 800 representative systems serving 10,000 or fewer people monitored for these and other unregulated contaminants during a 12-month period from January 2013 through December 2015. In Oregon, 65 public water systems monitored for these PFAS contaminants and there were no detections reported.

Fifth Unregulated Contaminant Monitoring Rule (UCMR5)

EPA’s Fifth Unregulated Contaminant Monitoring Rule (UCMR5) requires sample collection and analysis for 29 PFAS compounds and lithium between 2023 and 2025. In Oregon, a total of 127 public water systems will be monitoring under UCMR5. OHA follows up with public water systems that have UCMR5 PFAS detections by providing information on how the results compare to state/federal health advisory levels and proposed regulations, reporting requirements to customers, and information on available funding to address the contaminant. More information about UCMR5 can be found on EPA’s website here:

OHA PFAS Sampling Project

OHA conducted a PFAS drinking water monitoring project in 2021 through 2023 at public water systems in Oregon identified as at risk due to their proximity to a known or suspected PFAS use or contamination site. The purpose of this sampling project was to make sure customers are not being exposed to potentially harmful PFAS chemicals in their drinking water. The analysis was paid for through an EPA grant and was done at no cost to the water system. The Oregon Department of Environmental Quality lab analyzed 195 drinking water samples from 143 public water systems for 24 PFAS compounds using EPA Method 533. A list of the PFAS compounds included in Method 533 can be found here under the “Method 533” column.   

Proposed PFAS National Primary Drinking Water Regulation

On March 14, 2023, EPA released a proposed National Primary Drinking Water Regulation (NPDWR) for six PFAS chemicals. EPA is proposing to set a Maximum Contaminant Level (MCL) of 4.0 parts per trillion (ppt) for PFOA and PFOS and a hazard index-based regulation method for four additional PFAS compounds: PFNA, PFHxS, PFBS, and HFPO-DA (commonly referred to as GenX chemicals). These chemicals are not currently regulated. Once final, both the MCL and hazard index will be legally enforceable levels, and if exceeded, the water system would be responsible for installing treatment or providing an alternate source of drinking water. More information about the proposed regulation can be found here:

Labs for PFAS Analysis in Drinking Water

OHA recommends public water systems that are interested in testing for PFAS in their drinking water use a lab that is accredited by the Oregon Environmental Laboratory Accreditation Program (ORELAP). See below for a list of ORELAP-accredited labs for the analysis of PFAS in drinking water:

For more information: