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What should I do about PFAS in my water?

A consumer guide for dealing with harmful PFAS

If you’ve been hearing more about PFAS, it’s because testing is increasingly detecting those harmful chemicals. What can you do if you have PFAS in your water? The answer is complicated. Here’s what to know about navigating threats from the chemicals.

What are PFAS?

PFAS, or per- and polyfluoroalkyl substances, are a class of more than 12,000 human-made compounds. Most Americans encounter them through the foods they eat, dust, and hand-to-mouth contact with PFAS-treated products. But you probably wouldn’t know it, because the chemicals are often odorless, colorless and tasteless. They accumulate in the environment and human bodies over time and do not easily break down, which is why some people call them “forever chemicals.” Increased testing is revealing PFAS in public drinking systems, groundwater and surface waters nationwide.

Will they harm me?

Scientists haven’t studied most PFAS deeply, but they link two of the most widely researched, PFOA and PFOS, to a range of health problems. Those include altered hormone levels, decreased birth weight, digestive inflammation and ulcers, high cholesterol, hypertension in pregnancy, kidney and testicular cancers and reduced vaccine effectiveness in children.

Where do PFAS come from?

PFAS are ubiquitous in consumer and industrial products, such as fabric stain protectors, firefighting foam, food packaging, lubricants, non-stick cookware, paints and waterproof clothing.

Tap water is typically the main source of exposure for people living near contaminated sites. But that doesn’t mean you have to stop showering. Little PFAS enter the body through the skin, according to the U.S. Centers for Disease Control and Prevention. Bathing and washing dishes with PFAS-contaminated water is unlikely to significantly increase exposure, the agency says.

How much PFAS is harmful?

Virtually no amount of PFAS is safe for consumption, according to the U.S. Environmental Protection Agency. In June, the agency updated draft health advisories for PFOA and PFOS. It warned against consuming more than 0.004 parts per trillion (ppt) and 0.02 ppt of the two compounds, respectively. That equates to about 4 drops and 20 drops of water in 1,000 Olympic-sized swimming pools.

How do I know if my water is safe to drink?

The answer depends on who you ask and where you live. The EPA sets standards for public drinking water systems, which must treat water to within acceptable limits for contaminants. No national standard yet exists for PFAS, so many states have stepped in to set their own. Others have none.

What if I have a private water well?

Neither the EPA nor the state regulates private water wells. You can pay to have your water tested. Many laboratories can test water for PFAS for a fee.

How can I treat my water?

Multiple filtration systems can remove PFAS from tap and well water. You can install them where water enters a house or building or on a specific fixture. Treatment methods include granular activated carbon, ion exchange resins and reverse osmosis. The EPA does not recommend that contaminated households switch to bottled water, because the U.S. Food and Drug Administration has not established PFAS quality standards in bottled water, nor does it require testing for PFAS, although the International Bottled Water Association says its members test for the chemicals annually.

What are my filtration options?

Granular activated carbon systems, generally the least expensive treatment option, can remove some PFAS, including PFOA and PFOS. They work by binding PFAS to a porous carbon surface. But molecularly shorter chemicals, known as short-chain PFAS, may slip by. You can install the filter as a household unit or in sinks, faucets, refrigerators and pitchers. Some health officials recommend purchasing a device certified by the American Standards Institute and NSF, a product testing and certification organization.

Ion exchange resins act like little magnets that capture PFAS molecules. They are generally more effective than activated carbon, especially at snatching short-chain PFAS. Both technologies often cost less than reverse osmosis systems, which can run upwards of $1,000 to $2,000. That depends on the size of the system and the amount of water to be treated and stored before use.

Reverse osmosis devices force high-pressure water through a membrane with small pores to separate chemicals, including short-chain PFAS, from water. However, the technology requires a large volume of water, and it discharges PFAS-tainted backwash into sewer or septic systems — potentially reintroducing the contaminants into the environment.

If you can afford it, you can use multiple treatment systems in succession to increase effectiveness. That process is called a “treatment train.”

How well do these systems work?

Each technology can reduce many types of PFAS to non-detectable levels, exceeding 99% removal in lab and real-world settings, according to EPA reviews of scientific studies. However, not all devices are equally effective.

Researchers at Duke University and North Carolina State University tested 76 point-of-use filters and 13 point-of-entry systems and found that reverse osmosis filters and two-stage filters that utilized a treatment train reduced PFAS by 94% or more.

On average, activated carbon removed just 73% of PFAS contamination. But the carbon filters performed inconsistently. Sometimes they removed all PFAS, while at other times they had no effect.

Properly maintaining the systems matters, too. You should replace filters or cartridges according to manufacturer instructions, because PFAS can break through a broken or saturated system.

Do treatment systems carry drawbacks?

Yes. They can leave behind contaminated waste, including filters and resins. Those might go to a landfill or incinerator, where they could reintroduce PFAS into the environment. Researchers are studying methods of destroying PFAS-tainted materials — ranging from electrochemical oxidation to ball-milling — but according to a U.S. Government Accountability Office review, no methods can yet “fully destroy PFAS at full scale.”

Small water systems will face even greater filtration challenges than homeowners, said David Cwiertny, a University of Iowa engineering professor and director of the Center for Health Effects of Environmental Contamination. “They'll have to figure out how to dispose of it in a way that doesn't just put it back into the environment and have it be somebody else's problem.”

This story is a product of the Mississippi River Basin Ag & Water Desk, an editorially independent reporting network based at the University of Missouri School of Journalism in partnership with Report For America and the Society of Environmental Journalists, funded by the Walton Family Foundation.