PFAS in Tap Water: How to Find Out What's in Your Water and Choose a Filter

You fill a glass from the kitchen tap without thinking about it, the same way you have a thousand times. Then you read a headline about "forever chemicals" in drinking water, and suddenly that glass looks a little different. What's actually in there? Should you be worried? Should you buy a filter, and if so, which one?

PFAS have become one of the biggest environmental health stories of the past few years, and for good reason. They're widespread, they last a very long time, and researchers are still learning about their effects. The good news is that you can find out what's in your water and take practical steps to reduce your exposure without panicking.

What are PFAS?

PFAS stands for per- and polyfluoroalkyl substances. It's a large group of thousands of human-made chemicals that have been used since the 1940s because they resist water, grease, stains and heat. You'll find them, or used to find them, in:

• Nonstick cookware
• Water-resistant clothing and outdoor gear
• Stain-resistant carpets and upholstery
• Some food packaging, like grease-proof wrappers
• Firefighting foam
• Some cosmetics and personal care products
• Industrial processes

They're often called forever chemicals because the strong carbon-fluorine bonds in their structure make them extremely slow to break down in the environment and in the human body.

How PFAS get into drinking water

PFAS can enter water supplies from:

• Industrial sites that made or used PFAS
• Military bases and airports where firefighting foam was used
• Landfills
• Wastewater treatment plants
• Farmland where certain biosolids were spread

Once in the environment, they can travel through soil into groundwater, rivers and lakes. A 2023 U.S. Geological Survey study estimated that at least 45 percent of the nation's tap water could contain one or more types of PFAS.

PFAS health effects: what's known

Research on PFAS is ongoing, and not all PFAS have been studied equally. The most studied are PFOA and PFOS, which were phased out of production in the U.S. but still linger in the environment. According to the EPA and other health agencies, exposure to certain PFAS has been linked to:

• Higher cholesterol levels
• Changes in liver enzymes
• Decreased vaccine response in children
• Lower birth weight
• Higher risk of kidney and testicular cancer
• Increased blood pressure or preeclampsia during pregnancy

The International Agency for Research on Cancer classified PFOA as carcinogenic to humans in 2023.

It's important to keep this in perspective. Most people in the U.S. have some PFAS in their blood. Risk depends on how much you're exposed to and for how long. Reducing your exposure, especially in drinking water, is a reasonable step, but there's no need to panic.

PFAS drinking water regulations

In 2024, the EPA set the first-ever national drinking water limits for several PFAS, including a limit of 4 parts per trillion for PFOA and PFOS, with public water systems given several years to comply. Since then, parts of the rule and its compliance timeline have been under review, so check the EPA's website for the latest status. Some states have also set their own limits.

If you use a private well, these rules don't apply. Well owners are responsible for testing their own water.

How to find out if PFAS are in your water

Read your water quality report

If you get water from a public utility, it's required to publish an annual water quality report, also called a Consumer Confidence Report. Search for your water utility's name plus "water quality report," or call them and ask:

• Have you tested for PFAS?
• What levels did you find?
• What are you doing to reduce them?

Check public databases

Some states publish PFAS testing results online. Nonprofit groups also map known PFAS contamination, though their data and standards may differ from government agencies.

Test your water

If you have a private well or want more information, you can have your water tested. Use a state-certified laboratory that tests for PFAS using EPA-approved methods. Your state or local health department can often point you to certified labs. Home test strips usually aren't sensitive enough to detect PFAS at the very low levels that matter.

Water filters that can reduce PFAS

Not all water filters remove PFAS. The most effective types include:

Reverse osmosis

Reverse osmosis systems push water through a very fine membrane and are among the most effective at reducing PFAS. They're usually installed under the sink. Downsides include cost, some water waste and the removal of minerals.

Activated carbon filters

Granular activated carbon and carbon block filters can reduce many PFAS, depending on the filter quality and how often you change it. These come in pitchers, faucet-mounted filters, under-sink systems and refrigerator filters.

Look for certification

The key is choosing a filter that's been independently certified to reduce PFAS. Look for:

• NSF/ANSI Standard 53 for PFOA and PFOS reduction (common for carbon filters)
• NSF/ANSI Standard 58 for reverse osmosis systems
• NSF/ANSI Standard 401 for some other contaminants

Check the product listing or the certifier's website to confirm that PFAS reduction is specifically included in its certification, not just general filtration.

Change filters on time

A filter that's past its replacement date may stop working well. Set a reminder to change cartridges as recommended.

Is bottled water better?

Not necessarily. Bottled water isn't automatically free of PFAS, and it comes with its own downsides, like cost, plastic waste and microplastics. Our guide to microplastics at home explains more. A certified home filter is usually a better long-term option.

Other ways to reduce PFAS exposure

Drinking water is just one source. You can also:

• Replace scratched nonstick pans, and consider stainless steel, cast iron or ceramic. See our guide to non-toxic cookware.
• Cut back on grease-proof food packaging, like microwave popcorn bags and fast-food wrappers.
• Skip stain-resistant treatments on new carpets and furniture.
• Check product labels for "PFAS-free" on outdoor gear and clothing.
• Dust and vacuum regularly with a HEPA vacuum, since PFAS can collect in household dust.
• Check fish advisories if you eat fish from local lakes and rivers.

Our guide to a healthy home environment has more tips.

PFAS and private wells

About one in ten Americans gets drinking water from a private well, and if that's you, the responsibility for testing sits with you. Wells near military bases, airports, industrial sites, landfills or farmland where biosolids have been spread are more likely to be affected, but contamination isn't limited to those places, because PFAS can travel through groundwater.

A few practical steps for well owners:

• Call your state or county health department. Many have PFAS testing programs, maps of known contamination or lists of certified labs, and some offer free or reduced-cost testing in affected areas.
• Use a certified lab that tests for a broad panel of PFAS using EPA methods. Ask what the report will include and how to read it.
• Retest periodically, especially if you're near a known source or levels were close to health guidelines.
• Install treatment if needed. Whole-house systems and point-of-use systems at the kitchen tap are both options. Your health department or a water treatment professional can help you decide.

How to talk to your water utility

It can feel intimidating to call your water company, but utilities get these questions all the time now. You might say: "I'd like to know whether you've tested for PFAS, what levels you found, and what your plans are to meet the federal limits." You can also ask whether results are posted online and when the next round of testing is scheduled.

If you're unhappy with the answers, local government meetings and public comment periods are good places to raise concerns. Water systems often respond to community pressure, and you're very unlikely to be the only person asking.

Keep perspective

It's easy to spiral when you read about forever chemicals, and that worry can be its own kind of stress. Remember that drinking water is one of the sources you can actually control. Get the facts for your area, take a sensible step like a certified filter if you need one, and then let yourself move on. Our guide to climate anxiety has helpful ways to cope with environmental worry without burning out.

Frequently asked questions

What are PFAS in water?

PFAS are a large group of human-made "forever chemicals" that resist breaking down. They can enter drinking water from industrial sites, firefighting foam, landfills and other sources.

How do I know if my water has PFAS?

Check your water utility's annual water quality report or contact them directly. If you have a private well, get your water tested by a state-certified lab.

Does boiling water remove PFAS?

No. Boiling doesn't remove PFAS and may even concentrate them slightly as water evaporates.

What water filter removes PFAS?

Reverse osmosis systems and certified activated carbon filters can reduce PFAS. Look for NSF/ANSI 53 or 58 certification that specifically includes PFOA and PFOS reduction.

Are PFAS dangerous?

Some PFAS have been linked to health effects like higher cholesterol, effects on the immune system and certain cancers. Risk depends on how much and how long you're exposed.

Clean water is a big part of environmental wellness. Take our free wellness wheel quiz to see how your environment is supporting your health.