How to Test Your Water for PFAS: EPA Method 537.1 in Plain English

If your ZIP-code lookup on CheckPFAS returns a HIGH or MODERATE risk verdict — or if you’re on a private well not covered by EPA monitoring at all — the next question is usually the same: can I get my own water tested?

The short answer is yes. The longer answer involves a specific EPA-approved lab method, costs of $300–$600, and a few decisions that determine whether the result actually answers your question.

What “PFAS testing” actually means

There is no single test that detects all PFAS. The chemistry — over 12,000 compounds in the family — means commercial labs test for a defined panel of named compounds, typically the same 29 covered under the EPA’s UCMR 5 monitoring program. The standard analytical procedure they use is EPA Method 537.1.

Method 537.1 is the EPA-validated procedure for measuring 18 PFAS compounds in drinking water using solid-phase extraction followed by liquid chromatography / tandem mass spectrometry (LC-MS/MS). It is the same method EPA labs use to generate the data on this site. When a private lab tells you they “use EPA Method 537.1,” they are using the exact procedure used to enforce the federal MCLs.

A more recent method, EPA Method 533, covers an additional 25 PFAS — including some shorter-chain compounds Method 537.1 misses. Some labs run both. If you have a specific concern about short-chain PFAS (PFBA, PFPeA, PFHxA) in your area, ask whether the lab can run Method 533.

What the test actually measures

For each compound in the panel, the lab returns either a numeric concentration in parts per trillion (ppt) or a “non-detect” — meaning the concentration was below the lab’s minimum reporting limit (MRL), typically 1.5–2 ppt for most PFAS.

A typical result sheet from a 537.1 panel includes:

• Detected concentration in ppt for each compound the lab found above the MRL
• The MRL itself, so you know the floor below which non-detects mean “below this threshold, not literally zero”
• The EPA MCL for any regulated compound, for comparison
• The chain-of-custody documentation confirming the sample was handled per EPA protocol

How much it costs

A 537.1 panel from a certified lab typically runs $300–$500 for the full 18-compound panel. If you want the Method 533 add-on (the 25 additional compounds), expect another $100–$200. Multiple-sample bulk discounts exist if you’re testing a well, a neighborhood, or a small water system.

The price reflects the analytical equipment time — LC-MS/MS instrumentation is expensive, and PFAS chemistry requires meticulous laboratory sample handling to avoid contamination from materials (most PTFE-containing labware is off-limits).

How to find a certified lab

The right starting point is your state environmental agency’s list of certified drinking-water testing laboratories. Every state maintains one; most are searchable online. Look for labs with EPA Method 537.1 or EPA Method 533 accreditation specifically — generic water-testing labs may not have these certifications.

The EPA also maintains a national list of laboratories certified under the federal Safe Drinking Water Act, accessible via the state primacy agency.

If you’d rather not coordinate with a local lab, mail-in test kits handle the logistics: they ship the sampling materials, you collect the sample, and an accredited lab runs the analysis. Two consumer options are Cyclopure’s PFAS Water Test Kit (a PFAS-focused kit covering 55 compounds for about $85) and Tap Score by SimpleLab (14- to 40+-compound panels, roughly $275–$845, plus broader water-quality options). Either way, confirm the kit covers EPA Method 537.1 or 533 before ordering.

When you contact a lab, three questions to ask:

1. Which method do you use, and what compounds does it cover? Confirm 537.1 (minimum) or 537.1 + 533 (preferred).
2. What is your minimum reporting limit? The lower the better — ideally below 2 ppt for PFOA and PFOS, since EPA’s federal MCL is 4 ppt.
3. Do you provide sampling instructions and bottles? Reputable labs ship pre-cleaned sample bottles with explicit protocol — including which fittings, gloves, and storage to use. Do not use your own bottles.

How to collect the sample

The collection procedure matters as much as the analysis. PFAS contamination is everywhere in modern materials — Teflon tape, waterproof gear, certain plastics, certain detergents — and a contaminated sample bottle or sloppy hand-off can produce a false detection.

Follow the lab’s protocol exactly. Most labs require:

• First-draw cold tap water from your kitchen tap or main service point
• Nitrile or non-fluorinated gloves during collection
• Pre-cleaned glass or polyethylene bottles supplied by the lab
• No Teflon-coated containers, no PTFE tape, no greaseproof packaging anywhere near the sample
• Same-day or next-day shipping in a chilled cooler with ice packs

If you skip steps, the result is at best uninterpretable and at worst misleading. The chain of custody is what makes a private-lab result actionable.

How to interpret your result

When the results come back, compare each detected compound to its EPA limit:

• PFOA · MCL = 4 ppt
• PFOS · MCL = 4 ppt
• PFNA · MCL = 10 ppt (under reconsideration as of May 2025)
• PFHxS · MCL = 10 ppt (under reconsideration)
• HFPO-DA (GenX) · MCL = 10 ppt (under reconsideration)

If any single result exceeds its MCL, you have actionable contamination — the right next step is a certified PFAS-removal filter (reverse osmosis or NSF/ANSI 58 certified carbon block) and, if you’re on a public utility, contacting them about their compliance plan.

If all results are below their MCLs but above the MRL, you have detected PFAS but at concentrations EPA considers below the level requiring action. Some readers — particularly those with pregnant household members, infants, or compromised immune systems — choose to filter anyway as a precaution. That’s a personal call; the EPA does not require it.

If all results are non-detects, your sample contained no PFAS above the lab’s reporting floor. This is the best outcome available from the method.

When private testing is most useful

Private testing is most useful in three scenarios:

1. You’re on a private well. EPA’s MCLs and CheckPFAS data don’t cover you. The only way to know is to test.
2. Your public utility hasn’t tested recently or shows older data. Tap water at your specific home may differ from the entry-point measurement EPA shows for your system.
3. You live near a known PFAS source — a military base with documented AFFF release, a fluorochemical manufacturing site, a major airport. Localized contamination can be much higher than utility-wide averages.

Outside of these cases, the EPA’s published data on the system that serves you is generally sufficient. Save the $400 unless your situation suggests otherwise.

A note on home test kits

A growing number of home test kits sold via Amazon and direct-to-consumer brands claim to detect PFAS for $20–$50. As of 2026, none of them use EPA Method 537.1 or any equivalent validated procedure. They typically use colorimetric or strip-test chemistry with detection thresholds in the parts-per-billion range — three orders of magnitude higher than the parts-per-trillion levels at which PFAS health effects occur.

A home kit that returns “no PFAS detected” tells you essentially nothing about whether you have a 4 ppt PFOA exposure, because the kit’s floor is 1,000 ppt or higher. Save the money. If you want a real answer, send a sample to a 537.1 lab.

Where to go next

If you’ve already got a result you want to interpret, see our PFAS Compound Guide for what each detected compound means and what’s known about its health effects. If you’re on a public water system and haven’t yet, look up your ZIP — EPA testing may already have the answer for you. And if you’re shopping for a filter to address a confirmed detection, our PFAS-certified filter reviews rank options by removal performance and verified NSF certification.