Nearly Half Of US Drinking Water Contains PFAS — How Worried Should We Be?
Talk of tap water safety has picked up in the U.S. over the last few years—and for good reason. Crises like those in Flint, Michigan, and Jackson, Mississippi, have demonstrated how fragile our water systems really are, and research has questioned how safe the chemicals in our water (particularly PFAS) really are.
We spoke with a lead author of the report to learn more about the importance of this new finding and what it means for your water supply.
Testing PFAS straight from the tap
Per- and polyfluoroalkyl substances (PFAS) are a group of human-made chemicals known as "forever chemicals" because they linger in the environment—and in human bodies.
Exposure to high levels of PFAS has been linked to challenges with metabolic2 and thyroid health, adverse birth outcomes3, and in some extreme cases, higher incidents of cancer. PFAS are less than 100 years old (we first started using them to make water- and oil-resistant products in the 1940s), so there are still a lot of unanswered questions about how prevalent they actually are in our water supply.
Up until this point, most PFAS testing has been done at water treatment plants—not kitchen sinks themselves. In-home testing can be logistically difficult, but it's something that the USGS wanted to prioritize in this round of research because, as environmental organic chemist Kelly L. Smalling, MSPH, explains, "That's where exposure actually happens."
"Most of the information available on PFAS is at the drinking water treatment plant or in the surface water and groundwater wells that actually supply them. But then there are miles of infrastructure between the treatment plant and your home," Smalling, who worked on this new study, says on a call with mindbodygreen. "We don't really know how or if it changes as it moves through the distribution pipeline."
To find out how many PFAS are actually present at the tap level, the USGS worked with a network of volunteers to collect water samples from 716 residences across the U.S. This included a mix of rural and urban residences and public water supplies and private wells. Volunteers sent samples to laboratories to be tested for 32 types of PFAS.
While the USGS has conducted in-home PFAS testing before, it's been on a much smaller scale. This new research aimed to paint a more comprehensive picture of how many chemicals are actually present in our drinking water and how it varies across the country.
What did they find?
In this study, 45% of U.S. drinking water samples contained at least one type of PFAS. The most common types of PFAS were PFBS4, PFHxS, and PFOA5—found in approximately 15% of the samples. Exposure to these specific chemicals has caused adverse health effects in animal research, but their impacts on humans are unclear.
The amount of PFAS found in tap water varied from state to state and region to region. "Based on our analysis, higher concentrations of PFAS and more PFAS were observed in taps that were collected near urban centers, as well as potential sources of PFAS like airports, wastewater treatment plants, and military installations," says Smalling. Potential hot spots include more developed areas like the Eastern Seaboard, the Great Plains, the Great Lakes, and central and Southern California.
Tap water tested from rural areas in the Arid West and the Pacific Northwest did not contain any PFAS, Smalling notes.
"The other piece of the important puzzle is private wells," she adds. We know very little about the water quality of privately owned wells, so the USGS aimed to test nearly as many private wells as they did public water sources in every state sampled. They found that across the board, PFAS levels were actually pretty consistent between private and public water sources.
This means that private well owners could look to nearby public supply information to get a better idea of what's in their water. "It's not going to be a 1:1 relationship," she explains, "but at least it gives them a starting point—which they didn't have a month ago."
What should I do with this information?
If you're concerned about chugging down PFAS, Smalling recommends doing some research on your water supply. Some states are required to monitor and report PFAS levels while others aren't, so check on your local policy and the results of your latest water quality report for more information. (This Public Water Supply map from the EPA can get you started.)
Right now, there is no federal drinking water standard on PFAS. However, the EPA just introduced a new regulation that would limit the use of six of the most common PFAS. The agency is also conducting water quality tests across the country6 to help them determine any other unregulated contaminants of concern.
Until tighter nationwide standards are put in place, the EPA says that using an activated carbon filter at home is your best bet for removing PFAS from tap water. You can find these filters in pitchers, nozzles that attach to your sink, and in whole-home water purification systems.
The U.S. Geological Survey collected tap water samples across the country and found that 45% of them contained at least one instance of potentially harmful PFAS. We still have a lot to learn about how PFAS affect our health and in what quantities. New legislation on PFAS is in the works, but for now, if you're concerned about chemicals in your drinking water, the best course of action is to filter your water. Check out seven filters that water quality experts recommend here.
Emma Loewe is the Sustainability and Health Director at mindbodygreen and the author of Return to Nature: The New Science of How Natural Landscapes Restore Us. She is also the co-author of The Spirit Almanac: A Modern Guide To Ancient Self Care, which she wrote alongside Lindsay Kellner.
Emma received her B.A. in Environmental Science & Policy with a specialty in environmental communications from Duke University. In addition to penning over 1,000 mbg articles on topics from the water crisis in California to the rise of urban beekeeping, her work has appeared on Grist, Bloomberg News, Bustle, and Forbes. She's spoken about the intersection of self-care and sustainability on podcasts and live events alongside environmental thought leaders like Marci Zaroff, Gay Browne, and Summer Rayne Oakes.