More than 40% of U.S. tap water contains PFAS chemicals, according to a 2023 study by the U.S. Geological Survey. This widespread presence, coupled with the persistent threat of lead in older infrastructure, leaves many of us asking serious questions about what’s in our drinking water. It’s a valid concern: understanding the risks posed by contaminants like lead and PFAS is essential for protecting your health and making informed decisions about your water supply. We're going to break down the science, the health impacts, and the practical steps you can take.
Lead has been a known hazard for centuries, with its legacy still impacting communities across the nation. While lead pipes were banned in 1986, countless older homes and public buildings still have lead service lines, lead-soldered plumbing, or fixtures containing lead. When water flows through these components, lead can leach into your drinking supply. Even low levels of lead exposure can be harmful, and children are particularly vulnerable.
For children, lead exposure can cause irreversible neurological damage, leading to developmental delays, reduced IQ, learning difficulties, and behavioral problems. The Centers for Disease Control and Prevention (CDC) emphasizes that there is no safe blood lead level in children. A 2012 study published in Environmental Health Perspectives found that even very low blood lead concentrations (below 5 µg/dL) were associated with decreased academic achievement in children.
Adults aren’t immune either. Lead exposure in adults can lead to kidney damage, reproductive issues, cardiovascular problems, and nervous system effects. The EPA has set the Maximum Contaminant Level Goal (MCLG) for lead in drinking water at zero, recognizing its severe toxicity, though the action level is 15 ppb (parts per billion) at the tap. This means that if 10% of samples exceed 15 ppb, water systems must take action.
While lead service lines are the most significant contributor, other components within your home’s plumbing can also introduce lead. Brass or chrome-plated brass faucets and fixtures, as well as lead solder used in plumbing before 1986, are common culprits. Even if your municipality replaces their lead service lines, you might still have lead sources inside your home. This is why targeted testing and remediation are so important.
In some cities, like Chicago, the challenge of replacing lead service lines is immense, affecting hundreds of thousands of homes. You can learn more about how lead affects communities and what solutions are being explored by visiting our page on Lead Contamination in Water. For a deeper dive into lead's pervasive nature, explore our detailed content on lead.
Per- and polyfluoroalkyl substances (PFAS) are a group of over 12,000 synthetic chemicals that have been used in various industrial and consumer products since the 1940s. They’re known as “forever chemicals” because they break down very slowly in the environment and can accumulate in our bodies. You’ll find them in non-stick cookware, stain-resistant fabrics, firefighting foams, and some food packaging. Their widespread use means they enter our water systems through industrial discharges, landfill runoff, and even air deposition.
Research on PFAS is ongoing, but studies have linked exposure to a range of health issues. The Agency for Toxic Substances and Disease Registry (ATSDR) highlights several concerns, including increased cholesterol levels, changes in liver enzymes, decreased vaccine response in children, increased risk of high blood pressure or pre-eclampsia in pregnant women, increased risk of kidney or testicular cancer, and effects on the immune system and hormone function. A 2022 review in Environmental Science & Technology summarized evidence of PFAS disrupting metabolic processes and increasing obesity risk.
Unlike lead, which often poses an acute poisoning risk at higher levels, PFAS concerns often revolve around chronic exposure to low levels over a long period. The EPA has recently established legally enforceable maximum contaminant levels (MCLs) for six PFAS compounds in drinking water, with PFOA and PFOS set at 4 parts per trillion (ppt) each. These new regulations signify a growing recognition of the severity of PFAS contamination.
PFAS compounds are manufactured chemicals, so their presence in water is directly related to human industrial activity. Facilities that produce or use PFAS, military bases where firefighting foam was deployed, and wastewater treatment plants are frequent sources. These chemicals are highly mobile in water, meaning they can travel long distances from their origin points, affecting groundwater and surface water supplies far and wide. This makes them a challenging contaminant to manage and remove.
When we compare lead and PFAS, it's not simply a matter of saying one is worse. They're dangerous in different ways, on different timelines, to different people. The honest answer is that the more dangerous contaminant is the one that's actually in your water at a level that matters, and the only way to know that is to test.
That said, the two do line up differently across the things that count.
Toxicity and who's most at risk. Lead is an acute, well-proven neurotoxin, and its worst damage lands on young children and developing fetuses, whose brains it can harm permanently. PFAS harm is subtler and slower: raised cholesterol, immune and hormone effects, and higher risk of kidney and testicular cancer built up over years of low-dose exposure. If you have a young child or you're pregnant, lead is the more immediate threat. Across a whole adult lifetime, chronic PFAS exposure is the quieter, longer-running one.
How much we know. The science on lead is a century deep and settled, down to effects at very low blood levels. PFAS research is younger and still moving, which cuts both ways: regulators keep tightening limits as evidence accumulates, so today's "acceptable" number may not hold.
How they get into your water. Lead is a plumbing problem. It enters after treatment, from your service line and fixtures, so it's intensely local and one home can be fine while its neighbor isn't. PFAS is a source-water problem, entering upstream from industry, firefighting foam, and landfills, so it tends to affect a whole system or region at once.
The regulatory lines. The EPA sets the lead action level at 15 ppb (dropping to 10 ppb under the 2024 Lead and Copper Rule Improvements), with a health goal of zero. For PFAS, the EPA finalized enforceable limits in 2024 that put PFOA and PFOS at just 4 parts per trillion, roughly a thousand times lower by concentration, a sign of how potent these compounds are.
How hard they are to remove. Here's the good news, and it's the same for both. A reverse osmosis system or a filter certified to the right standards knocks down lead and PFAS. So while the contaminants differ, the fix at your tap often doesn't.
Worry about the one you have. A parent in a pre-1986 home with lead service lines should treat lead as the priority and start with a lead water test. Someone downstream of a manufacturing plant or military base should look hard at PFAS. Plenty of homes have some of both. Enter your zip code to see which contaminants have actually shown up in your local system, then match your filter to the real problem rather than the scary headline.
Lead is the more immediate danger to young children because it causes permanent, well-documented brain and developmental harm even at low levels. PFAS is a real concern too, but its effects are slower and accumulate over years.
Yes. Reverse osmosis systems and filters certified to NSF/ANSI 53 (lead) and NSF/ANSI 58 or P473 (PFAS) can reduce both. Check the certification for the specific contaminant before buying.
Both are widespread. Millions of homes still have lead service lines, and a 2023 U.S. Geological Survey study estimated PFAS in roughly 45% of U.S. tap water. Testing your own supply is the only way to know what you're dealing with.
Check your water quality by zip code to check for lead and other contaminants in your area. Find water filters that remove PFAS – many of the same systems that remove PFAS also handle lead. Get a detailed water quality report to see exactly what's been detected in your water supply.
Check your water now. Enter your zip code at KnowYourExposure.com to see what contaminants have been detected in your local water supply – including PFAS, lead, and other regulated compounds.