PFAS Drinking Water Standards, Testing, and Treatment

PFAS chemicals are found in surface water, groundwater, and soils where they can persist for decades. New rules in Pennsylvania recently limited the amount of PFAS in public drinking water, but residential well owners are responsible for determining if PFAS poses a risk to their water supply.

PFAS stands for per and polyfluoroalkyl substances. They are man-made chemicals that have been produced for decades in the United States for various industrial and home applications. Due to their widespread use, PFAS have been reported in surface water, groundwater as well as soils across the globe. However, higher concentrations have been measured in high-use areas such as military bases, fire training centers, manufacturing plants, as well as disposal sites such as dumps, landfills, and fields where contaminated biosolids have been spread.

PFAS are comprised of many different chemicals but the two most cited are perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). PFAS are commonly found throughout our environment and even the human body because they are not degraded by sunlight and are not chemically or biologically degraded in soil, air, or water. Because they are difficult to break down and are also easily dissolved in water, PFAS have been detected in soils, surface water, and groundwater wells across the globe.

Research studies have found that over a lifetime of exposure, very low levels of PFAS have been linked to a variety of serious health effects in both children and adults. These include various developmental and immune system effects, damage to the thyroid, liver, and other organs, and some evidence of possible cancers. Health effects have also been reported in fetuses and infants.

Drinking water is only one possible source of PFAS in the human body.  You can also be exposed by eating food that is exposed to PFAS while being grown or from food packaging. Humans are also exposed to PFAS through contaminated soil or dust or from products that are made from PFAS. Individuals should speak with a medical professional if they are concerned about their potential overall exposure to PFAS.

Drinking Water Standards

In April 2024, the US EPA finalized primary drinking water regulations for 6 PFAS as part of its duties to protect human health under National Safe Drinking Water Act. The regulations established maximum contamination levels (MCLs) shown in the table below.

As a result of the federal regulations, public water providers nationwide have until 2027 to complete initial monitoring of the water they distribute to their customers to determine if PFAS levels are below the new MCLs.  If testing reveals PFAS concentrations above any MCL, water providers may need to install water treatment equipment or start using an alternative water source to comply with national drinking water laws by the year 2031.

Pennsylvania's PFAS Rule

Independent of the federal rulemaking process, Pennsylvania finalized its own enforceable MCLs for two PFAS chemicals in drinking water in 2023. This rule was created after the Pennsylvania Department of Environmental Protection (DEP) led an extensive review of available information on the human health risks posed by these chemicals, analyzed the results of a statewide testing program, and considered input from individuals and organizations impacted by the proposed rule. Pennsylvania set an MCL of 14 parts per trillion (ppt) for PFOA and 18 ppt for PFOS. Because EPA's MCLs for PFAS substances are lower than the MCLs Pennsylvania recently established, public water providers will ultimately need to comply with the federal MCLs to avoid rule violations. But before the federal rule fully takes effect in 2029, public water providers in Pennsylvania will need to ensure they comply with the monitoring and response guidelines established by Pennsylvania's PFAS rule.

Both Pennsylvania's and EPA's PFAS rules only apply to public drinking water systems. Residents who get their drinking water from their own private well, spring, or cistern are not regulated under these laws. Instead, these households are responsible for their own water testing and treatment if they decide it’s needed.

Testing PFAS in Pennsylvania

If you have a private groundwater well or spring and are concerned about possible PFAS contamination you may wish to get your water tested by a state-accredited laboratory. Based on current testing studies the risk of PFAS contamination in groundwater is low but more common in wells located near places where PFAS chemicals were historically used such as military bases, fire training sites, dumps, landfills, manufacturing facilities, and fields where contaminated biosolids (byproducts from wastewater treatment) have been spread.

Table 2 below shows the current laboratories (as of May 2025) across Pennsylvania capable of testing for PFAS in water. Some can also test PFAS in soil, biosolids, and plant/animal products. PA DEP provides accreditation to all these laboratories for testing PFAS in water, but at the moment, there is no accreditation program for other biosolids, soils, or plant tissue.  

The US EPA has developed and validated different testing methods for PFAS in water, wastewater, soils, biosolids, and tissue samples. The two main methods for drinking water are US EPA Method 537.1, which measures 18 PFAS compounds, and Method 533, which measures 25. While Method 533 is more comprehensive, both methods have several PFAS compounds in common and include those that are the focus of state and federal drinking water regulations. Method 1633 measures 40 PFAS compounds in wastewater, surface water, groundwater, soil, biosolids, sediment, landfill leachate, and fish tissue. Laboratories use different testing methods depending on their accreditation, analytical capabilities, and the type of sample to be tested. Learn more about the different EPA PFAS testing methods here: PFAS Analytical Methods Development and Sampling Research.

Because PFAS are emerging contaminants, there are only a few laboratories in the state that are accredited by the DEP to test for them, but this number may grow in the coming years. Many laboratories provide sampling kits containing bottles and detailed method-specific instructions for collecting, handling, and shipping samples. Because PFAS testing requires especially complex testing instruments and lengthy methods, testing for PFAS can cost around $250 to $500 per sample, depending on the type of sample (e.g., soil, water, tissue) being tested. 

The most up-to-date list of state-accredited labs for water testing is available by visiting the search tool for accredited environmental labs on DEP's website. 

Home Water Treatment Systems to Remove PFAS

Several relatively common water treatment devices are effective in removing PFAS chemicals from water. Since the evidence indicates the majority of PFAS exposure occurs from drinking or ingesting water instead of from skin contact, small point-of-use (POU) treatment systems that are located on one faucet can be used to avoid most PFAS exposure. These include reverse osmosis (RO) and granular carbon filtration (GAC) devices. There are also larger point-of-entry (POE) water treatment systems that can be used to treat all the water entering the home. These include anion exchange units (similar to water softeners), larger GAC filters, or whole-house RO units.

If you are looking for a filter to protect against PFAS you should only consider devices that have been certified by a recognized third-party testing organization such as the National Sanitary Foundation (NSF) or Water Quality Association (WQA). The EPA has also conducted its own research on PFAS treatment technologies and in 2020 published a study on POU and POE treatment systems for removing PFAS. The study found that POU and POE systems can effectively and affordably remove PFAS from home drinking water if they are designed and maintained properly.

More Information

Information from Penn State Extension

• Understanding PFAS – What They Are, Their Impact, and What We Can Do
• Guide to Addressing PFAS in Drinking Water

Numerous organizations have many educational resources on PFAS at the links below:

• Pennsylvania Department of Environmental Protection, PFAS in Pennsylvania
• Centers for Disease Control PFAS fact sheet
• U.S. Environmental Protection Agency PFAS website
• National Ground Water Association PFAS information