Your Tap Water May Hold Twice the Forever Chemicals the EPA Reports

The number you have been told about PFAS in your drinking water may be only half the story. A new study published this week in Cell Reports Sustainability found that forever chemical levels in U.S. tap water could be twice as high as federal data shows. The Washington Post and several other outlets reported on the findings, and they deserve your attention. The research does not point to a new spill or a new disaster. It points to a flaw in how the numbers get counted, and that flaw makes a serious problem look smaller than it really is. If you drink tap water, this affects you.

PFAS are man-made chemicals found in cookware, cosmetics, and food packaging. Scientists call them forever chemicals because they refuse to break down in the environment. They seep from products into soil, from soil into groundwater, and from groundwater into the water that comes out of your faucet. Once inside your body, they build up over time instead of washing out. Research links PFAS exposure to cancer, heart problems, and reproductive and developmental defects. Those risks are why even tiny amounts in drinking water draw such close attention.

Here is where the EPA’s numbers fall short. Under a national testing program, public water systems must test for 29 different PFAS chemicals. Labs can only measure down to a set minimum, known as the reporting limit. When a chemical shows up below that line, the result gets logged as “below the limit” with no exact number attached. When researchers and agencies later calculate national averages, those results are often counted as zero. Zero means nothing is there. Below the limit only means the lab could not pin down an exact amount. That difference sounds small, and it changes everything.

The gap turned out to be enormous. Researchers at Texas Christian University studied more than 1.8 million test records from the EPA’s January 2026 data release, which covered 9,991 community water systems. They found that 98 percent of the individual results fell below the reporting limit. The team then used statistical models to estimate the amounts hiding under that line. Their conclusion was blunt. The standard method captures only 44 percent of the true average PFAS concentration. In plain terms, the real level is more than double what the zeroed-out math suggests.

The study has limits, and you deserve to know them. The team did not collect new water samples. They reworked existing EPA data with computer modeling, so the results are estimates and not direct measurements. The researchers also note that higher estimated levels in water do not automatically mean people take in more PFAS than we thought. One researcher quoted by Inside Climate News pointed out that the EPA assumes drinking water makes up about 20 percent of total PFAS exposure. The EPA did not immediately comment on the findings when the Washington Post reported them. Even with those cautions, the main point stands firm. A result below the reporting limit does not mean the chemical is gone, and PFAS contamination is likely more widespread than most people assume.

The federal limits add to the problem. The EPA caps PFOA and PFOS, the two most studied PFAS chemicals, at 4 parts per trillion in drinking water. That number is also the reporting limit for both chemicals, so a result under 4 gets logged as zero. The EPA’s own health goal for these two chemicals is zero, because the agency has determined that no level of exposure is risk-free. A water system can sit just under the legal limit and still carry a real dose of chemicals the EPA says are unsafe at any level. The legal limit and the safe level are not the same number.

Now look at the scale. An analysis from the Environmental Working Group suggests that about 176 million Americans use water from systems where at least one PFAS chemical was detected. That count came from the same federal data the new study questions. If true concentrations run higher than reported, more water systems could reach or exceed a threshold just above the EPA’s 4 parts per trillion limit. The lead researcher, Kharel, plans to repeat the analysis with newer EPA datasets, so the picture may sharpen soon. Until then, it is smart to treat the official numbers as a floor, not a ceiling.

You cannot taste PFAS. You cannot smell them. Boiling your water will not remove them. The most reliable protection happens at your own tap, with a filter built to handle them. Reverse osmosis is one of the most effective home filtration methods against PFAS, because it pushes water through a membrane fine enough to block these chemicals at the molecular level. Carbon filters can reduce some PFAS, but reverse osmosis also handles contaminants like nitrate and chromium-6 that carbon does not.

You cannot control how the EPA counts its numbers. You can control what comes out of your faucet. A Sanavia reverse osmosis system filters PFAS from your water, so your family does not have to rely on a figure that may be hiding half the truth. Check your local water report, see what your utility has detected, and decide what level of protection makes sense for your home. Clean water should not depend on a rounding rule.