PFAS in Drinking Water: What You Need to Know

PFAS (per- and polyfluoroalkyl substances) are synthetic chemicals found in the drinking water of an estimated 110 million Americans. Unlike hard water or chlorine, PFAS cannot be seen, smelled, or tasted. The only way to know if your water contains them is testing.

In April 2024, the EPA finalized the first-ever national limits for PFAS in drinking water, setting maximum contaminant levels of 4 parts per trillion (ppt) for PFOA and PFOS individually. Water utilities have until 2029 to comply. Until then, the water arriving at your tap may exceed these limits and your utility is not yet required to treat it. For a detailed breakdown of the regulation timeline and health research, see our PFAS reference page.

Should You Be Concerned?

The short answer is that PFAS exposure at levels commonly found in US tap water is associated with health effects including increased cholesterol, immune system suppression, thyroid disruption, and increased risk of certain cancers. These associations come from decades of epidemiological research, and the EPA's decision to regulate was based on this body of evidence.

That said, the dose matters. A home with 2 ppt of PFOA has a meaningfully different risk profile than a home with 40 ppt. This is why testing comes first. Acting without data means you might spend $300 to $1,500 on a system you do not need, or choose a system that does not address the specific PFAS compounds in your water.

How to Test Your Water for PFAS

Standard home test strips do not detect PFAS. You need a laboratory test that specifically analyzes for PFAS compounds. There are two practical options.

A certified lab test through a service like Tap Score or SimpleLab costs $150 to $350 and tests for 30+ PFAS compounds. You collect a sample at home, mail it in, and receive results in 1 to 2 weeks. This gives you the most complete picture of what is in your water and at what concentrations.

Your utility's annual Consumer Confidence Report (CCR) may include PFAS data, especially if your state requires reporting. However, these reports reflect the water leaving the treatment plant, not what arrives at your tap. They are a useful starting point but not a substitute for testing at your faucet.

You can also look up your city in our database to see reported PFAS levels and how they compare to the new EPA limits.

What Actually Removes PFAS

Not all water filters remove PFAS. Many popular pitcher filters and faucet-mount filters do not. The treatment technologies with verified PFAS removal are:

Reverse osmosis (most effective)

Under-sink reverse osmosis systems remove 90% to 99% of PFAS compounds including both long-chain (PFOA, PFOS) and short-chain variants that other methods can miss. An RO system is the highest-confidence option if your PFAS levels are significantly above the EPA limits. Most under-sink RO systems cost $150 to $500 and are suitable for drinking and cooking water. See our Reverse Osmosis guide for sizing and recommendations.

Activated carbon (granular or block)

High-quality activated carbon filters, particularly carbon block filters, can reduce PFOA and PFOS by 70% to 95% depending on the specific filter, contact time, and concentration. Carbon is less effective on short-chain PFAS. Whole-house carbon filters treat all the water entering your home but are more expensive. Under-sink and pitcher filters using NSF-certified carbon blocks offer a lower-cost option for drinking water only. See our Whole-House Filter guide, Under-Sink Filter guide, or Pitcher Filter guide.

Ion exchange (specialized resins)

Some whole-house and point-of-use systems use anion exchange resins designed specifically for PFAS. These are effective but less commonly available in consumer products. They are more common in municipal treatment systems.

What does NOT remove PFAS

Boiling water does not remove PFAS and actually concentrates them. Standard carbon faucet filters (like basic Brita tap attachments) have not been independently verified for PFAS removal. Water softeners do not address PFAS. UV treatment does not affect PFAS. If a product claims PFAS removal, look for NSF/ANSI 53 or NSF P473 certification, which specifically tests for PFAS reduction.

Recommended Approach

If you have not tested, start there. The cost of a lab test ($150 to $350) is far less than buying the wrong treatment system.

If your levels are below 4 ppt for PFOA and PFOS: Your water meets the new EPA standard. Ongoing monitoring is reasonable but immediate treatment may not be necessary.

If your levels are moderately above the limits (4 to 20 ppt): A quality under-sink carbon block filter or a pitcher filter with NSF P473 certification is a proportionate response for drinking water.

If your levels are significantly elevated (above 20 ppt): An under-sink reverse osmosis system is the recommended treatment for drinking and cooking water. For whole-house treatment, a carbon-based whole-house filter combined with an RO system at the kitchen tap covers both bathing exposure and ingestion.

Not sure which direction to go? Our Water Treatment Quiz factors in your specific contaminant concerns and recommends a system type based on your situation.