How To Filter Pfas Chemicals Out Of Your Home Water

This article was updated Wednesday, March 10, 2021

The family of fluorinated compounds known as PFAS chemicals includes more than than 4,700 chemicals – some linked to cancer, thyroid disease, weakened immunity and developmental defects, and others whose health furnishings are unknown. One affair'due south for sure: You don't desire them in your body.

Drinking h2o is one of the most common sources of exposure. PFAS chemicals could contaminate the drinking water for 110 million Americans nationwide. EWG'south interactive map shows areas of known contamination. If y'all know or doubtable these chemicals are in your tap water, the best fashion to protect yourself is by installing an in-home water filter. But which kind?

71 products are currently certified to reduce PFAS in water

Based on data from land health agencies, testing labs, scientific researchers and water filter companies, the most constructive choice for in-home handling of PFAS-tainted tap h2o is a contrary osmosis filter, followed by an activated carbon filter – a slightly lower-cost option.

Just many questions remain unanswered. More research is urgently needed to better understand how to ensure removal of the many types of PFAS compounds. To assist with your option, below are details of what is currently known.

Disclaimer: EWG is not recommending any specific brand of filter and cannot guarantee that a filter'due south performance will match the results reported below.

States Leading Response to PFAS Contamination Crisis

The Environmental Protection Agency has set a health advisory level for the two most-studied PFAS compounds in drinking water – PFOA, formerly used to make DuPont'due south Teflon, and PFOS, formerly an ingredient in 3M'south Scotchgard. The advisory level is lxx parts per trillion, or ppt, for the two chemicals combined. But the best and most current scientific inquiry says that's much too high, and the EPA'south advisory level is not legally enforceable.

That's why some states with extensive PFAS drinking water contamination are taking steps to set up more than health-protective limits or advisory levels. For instance, New Bailiwick of jersey has set a legal limit of 13 ppt for perfluorononanoic acid, or PFNA, and proposed enforceable limits of 14 ppt for PFOA and 13 ppt for both PFOS. Other states such as Washington, Michigan, and Northward Carolina are conducting additional testing to farther evaluate the extent of contamination in drinking h2o.

Some of these states have issued recommendations for water filters to remove PFOA and PFOS, including:

Michigan;
Minnesota;
New Hampshire;
New Bailiwick of jersey; and
New York.

Guidance and factsheet documents from these states recommend two types of filters for removing PFAS chemicals: activated carbon and contrary osmosis. U.s.a. provide data on the pluses and minuses of the two types, and tips on how to maintain them to ensure effective filtering. They also compare the two types of filter installations: "indicate of use," which are installed under the kitchen sink or in the refrigerator, and "point of entry," which treat the water for the whole house.

In communities with the worst contamination, such equally in Minnesota or Michigan, whole-house filtration is ofttimes used. It is effective, but expensive in comparison to point-of-apply filtration and may not be necessary in most cases. Farther, since whole-firm systems as well remove chlorine, they may introduce additional risks of harmful bacterial growth in plumbing.

Filters Certified for PFAS Chemical Removal

NSF International, a testing and certification company, developed a certification standard for removal of PFOS and PFOA in 2016. The certification requires that the filter reduce these 2 chemicals just to EPA's health informational level of 70 ppt. Currently, 71 products from vii manufacturers are certified to meet this standard.

Even so, drinking water tin can comprise other PFAS chemicals, sometimes at higher levels than PFOS and PFOA. PFOS and PFOA, which are at present banned, are called 'long-chain' compounds because they have eight carbon atoms, while the chemicals that have replaced them are called 'short-chain' compounds because they take fewer carbon atoms. While similar, these so-called "next-generation" compounds have different molecular structures, and the effectiveness of filters certified for PFOS and PFOA for removal of replacement PFAS chemicals is unknown.

Link to interactive map

Filter Testing by State Agencies

In 2007, the Minnesota Department of Health commissioned testing of home water filters to determine their efficacy in removing PFAS. Six activated carbon filters and eight contrary osmosis filter types were tested. The tests determined that four of the vi carbon filters and seven of the 8 opposite osmosis filters provided sufficient reduction of PFAS chemicals. In field testing, iv activated carbon devices and seven opposite osmosis systems, all equipped in tandem with activated carbon filters, removed PFOA, PFOS and PFBA to the detection limit of fifty ppt.

The study noted that for the carbon filters, the effectiveness of removal of PFOA, PFOS and some other chemic, PFBA, decreased over operating life in five of the six filters tested in laboratory conditions. That means that users will have to replace the filters on the recommended schedule to ensure effective filtration of PFAS chemicals.

In 2017, Minnesota released the results of a written report for a faucet-mounted carbon filter made by PUR. The filter was tested for seven PFAS chemicals typically seen in groundwater in Washington County in Minnesota. The state concluded that this low-cost filter could be used to effectively reduce PFAS contamination. Half dozen of vii contaminants including PFOA and PFOS were removed below the reporting limits of 5 and 10 ppt, respectively, accomplished in the 2017 study. In contrast, levels of the shorter chain PFBA were only reduced by 75 percent.

Filter Testing by Bookish Institutions

Professor Detlef Knappe and his research group at Due north Carolina State University take independently tested numerous home water filter options. To date they have tested at to the lowest degree 27 home-use filters.

Last twelvemonth, Knappe told the Star News of Wilmington, N.C. that an under-sink contrary osmosis filter was probably the best pick for home treatment. He said it'south non merely constructive, but its continued effectiveness can be hands verified with an electrical conductivity tester, an inexpensive tool that people can use at dwelling.

Detailed testing results were publicly presented in 2017 for 4 under-sink contrary osmosis filters and ane whole-house activated carbon filter. These filters that were tested for removal of a dozen PFAS chemicals, including both long-chain and curt-chain compounds.

Three out of 4 reverse osmosis filters reduced the long-chain compounds to below 10 ppt, with the other filter reducing them to a slightly higher level. The four reverse osmosis systems likewise removed between 95 and 99 percentage of brusque-concatenation compounds.

EWG Contacted H2o Filter Companies

EWG surveyed 51 water filter companies to find out about their filters' capabilities to remove PFAS. Nosotros heard back from 14 companies, but only four of them verified that their filters remove any PFAS chemicals.

Only Berkey provided EWG with test data for their carbon filters, which reported removal of nine PFAS chemicals, including PFOA and PFOS, all below the detection limit of 2 ppt. Even so, only 25 gallons of h2o were filtered, instead of the recommended 6,000 gallons to measure out lifetime efficacy. Aqua Systems and Triple Clear stated that removal for their products was only to the EPA advisory levels and Crystal Quest reported that removal was variable.

Reverse Osmosis Filters vs. Activated Carbon Filters

In general, reverse osmosis systems more consistently removed PFAS compared to activated carbon systems.

Most contrary osmosis systems too have the benefit of an additional activated carbon filtration stage included in the system. Opposite osmosis systems remove a wider range of other contaminants from drinking water and their effectiveness can be tested at home using an electrical conductivity meter. Just activated carbon filter systems are significantly less expensive than reverse osmosis systems. Carbon filters must be changed on schedule as they will lose their effectiveness over time.

Recommendations

Check out EWG's interactive PFAS map to see if your drinking water has high levels of PFAS chemicals or if at that place is a contagion site about your community.
If you live in an area with contamination, contact your local wellness department for current information.
If yous have a private well and doubtable PFAS contamination, consult your country health section nearly having your well tested.
The best bet to filter PFAS chemicals out of your water is an in-habitation reverse osmosis filter under your sink or at your tap. To ensure that the reverse osmosis filter is working, use an inexpensive conductivity meter. These filter systems remove ions and full dissolved solids in addition to other contaminants, and a low conductivity reading for the filtered water indicates that the filter is overall constructive.
Y'all tin can also consider an activated carbon filter that will well-nigh frequently provide effective removal. Results take been inconsistent and the filters become less effective with fourth dimension. If possible, choose a filter that has been tested for PFOS, PFOA and additional PFAS chemicals that may be nowadays in your water.

EWG Research Intern Michael Ong, Enquiry Analyst Carla Burns, and Senior Scientists Tasha Stoiber, Ph.D., and David Andrews, Ph.D contributed to research for this project.