The Environmental Protection Agency is moving to weaken national drinking water limits on the toxic “forever chemicals” known as PFAS. You may be asking: With federal safeguards at risk, how can I protect myself from these harmful substances in tap water?
PFAS, a class of thousands of synthetic chemicals, have been found in nearly half of drinking water supplies across the U.S. According to the EPA’s water monitoring data and state tests, PFAS have been detected in tap water serving 172 million people.
They are known as forever chemicals because they don’t break down in the environment. Exposure to PFAS is linked to cancer, reproductive harm, immune system damage and other health problems, even at low levels.
Drinking water limits set during the Biden administration would have led many water systems to install treatment technologies to reduce the amount of PFAS in the tap water of communities they serve. But now the Trump administration’s plan to undo some of these hard-won standards creates uncertainty about how water utilities will proceed.
Despite this regulatory back-pedalling, there are still steps you can take to tackle PFAS in your tap water. One of the simplest and most effective ways to protect your health is by using a water filter to reduce your exposure to PFAS.
When to consider a water filter
Start by checking EWG’s Tap Water Database to learn whether PFAS or other contaminants have been detected in your water system. EWG’s interactive map shows sites with known PFAS pollution.
If you rely on a private well and are concerned about contamination, consider getting your water tested, especially if you live near an industrial area or military installation.
Best types of filters for PFAS
Based on information from state health agencies, scientific studies and other tests, reverse osmosis filters are the most effective way to remove PFAS from tap water at home – but many models tend to be expensive, compared to carbon filters.
Activated carbon filters are also effective and can be a lower-cost option. Ion exchange technology can reduce PFAS too but is only used in a few home products. The cost varies depending on the type of installation.
Here’s how the different filter systems work:
Reverse osmosis
This type of system pushes tap water through a semi-permeable membrane that blocks particles larger than water molecules. It is effective for removing a wide range of contaminants, including PFAS. Systems sold for home installation often include one or more carbon-based filters, boosting their effectiveness.
Reverse osmosis filters are usually installed under the sink, but some models can be connected to the faucet or sit on the counter-top.
Carbon-based
Commonly known as granular-activated carbon or carbon block, these filters absorb contaminants as water flows through them. These types of filters are available in a range of styles, including faucet-mounted, under-sink, and pitchers. While performance varies significantly for different contaminants, multi-stage carbon-based filters are more effective at reducing PFAS.
In 2023, EWG tested several countertop filters and found that some reduced PFAS and a number of other contaminants effectively. These filters commonly use granular-activated carbon or carbon block technology. They also tend to be more accessible and affordable, especially for a short-term renter, whose lease may limit what can be installed.
Researchers in North Carolina tested water filters in 79 homes and found that about 75% of carbon-based filters significantly reduced PFAS in tap water. But performance varied across brands, so it’s important to choose a quality filter.
Ion exchange
This technology works by exchanging contaminants in the water for less harmful ions to trap certain contaminants. Ion exchange can reduce PFAS but is less common in point-of-use filters, or those designed for a single faucet.
Since ion exchange is more typical in whole-house systems or water softening systems, it may be more expensive than point-of-use systems.
For more details about how these filters work, see EWG’s Water Filter Guide.
Low- or no-installation options
Renters may prefer counter-top, faucet-mounted or pitcher-type filters.
Whole-house filter systems
These systems are often more expensive than other options. And they’re not necessary for most homes. A filter that treats the water you drink is usually sufficient to protect your health. In communities with the worst contamination, filtration for the whole-house is sometimes installed instead of a point-of-use device at the tap.
Test results show that in some cases, whole-house systems can actually increase PFAS levels in tap water. These whole-house systems also reduce chlorine, which could increase the risk of harmful bacterial growth in plumbing.
Filters that reduce PFAS also reduce other contaminants
In September, EWG scientists published a study that showed when PFAS are detected in drinking water at 4 parts per billion or higher, other pollutants like disinfection byproducts, metals, nitrate and organic contaminants are also present.
The good news? Filters that remove PFAS – such as reverse osmosis and carbon – can also reduce many other drinking water contaminants of concern.
Filter certification
NSF International, a testing and certification company, developed a standard in 2016 for filters that remove PFOS and PFOA, two of the most notorious and well-studied PFAS. The certification only requires filters to reduce levels of these chemicals to 70 parts per trillion, or ppt, a level based on outdated EPA guidelines.
The EPA’s PFOA and PFOS drinking water standard, set in 2024, is much stricter, at just 4 ppt. The agency is working with standard-setting organizations to update filter certification requirements to meet the more health-protective limits for the two forever chemicals.
For now, if you’re shopping for a water filter, look for these labels:
- NSF/ANSI 53: Filters with this certification have been tested to reduce PFAS to below 20 ppt.
- NSF/ANSI 58: This standard applies to reverse osmosis systems, which are highly effective at removing PFAS from water.
Filters maintenance is essential
Water filters are effective only if they are properly maintained. If filter cartridges are not replaced as recommended by the manufacturer, concentrated pollutants can leach back into drinking water. To keep your filter working most effectively, make sure to follow the replacement schedule in its instructions.
Recommendations
Filtering drinking water is one of the easiest ways to reduce exposure to PFAS and other harmful pollutants.
- Check your water. Use EWG’s Tap Water Database and interactive map to learn whether PFAS and other contaminants are in your water.
- Choose the right filter. EWG’s filter guide helps you compare different versions and find one that meets your needs.
- Use proven technologies. Reverse osmosis and carbon-based filters are effective for removing PFAS and other contaminants.
- Maintain your filter. Because it bears repeating – follow the manufacturer’s instructions and replace filter cartridges on time.