PFAS in Private Wells: A Plain-English Testing Guide

About 15% of US households rely on a private well. If that’s you, the EPA’s 2024 PFAS rule and most of the data on this site don’t apply: federal MCLs only govern public water systems, and our ZIP-level results are aggregated from utility testing. Whether your well has PFAS — and how much — is a question only your own sample can answer.

The good news is that the testing process is straightforward and well-defined. Here’s what it actually involves.

When testing makes sense

You don’t need to test every well, but a few situations make it worthwhile:

• You live near a known PFAS source. Military airfields, civilian airports with firefighting training, fluorochemical manufacturers, paper mills, chrome platers, textile finishers, and certain landfills are the most common upstream contamination points. The EPA Cleanups in My Community tool lets you check for active investigations near your address.
• Your county shows PFAS detections in nearby utility data. The national heatmap gives you that view at a glance. If your neighbors on city water are seeing detections, your aquifer might be drawing from the same plume.
• You’re newly relocated and don’t know the well’s history. A baseline test is reasonable peace of mind, especially before pregnancy or with young children in the household.
• You’ve simply never tested. Routine well testing in the US tends to focus on bacteria, nitrates, and arsenic — PFAS is rarely included by default.

If none of these apply to you, the practical risk of a typical rural well is generally low, and waiting for state programs to come through your area is a reasonable choice.

What test method to ask for

There are two EPA-validated methods you’ll see on lab quote sheets:

• EPA Method 537.1 — covers 18 PFAS compounds, including all 5 with federal MCLs (PFOA, PFOS, PFNA, PFHxS, HFPO-DA). This is the standard most utilities use.
• EPA Method 533 — covers a slightly different set of 25 PFAS, including some shorter-chain compounds (PFBA, PFHxA) that 537.1 misses.

For a homeowner, 537.1 is sufficient unless you have a specific reason to look at short-chain PFAS. Some labs offer a combined panel covering both methods, often called “29-PFAS” or “30-PFAS,” which mirrors what UCMR 5 tested.

What to avoid: home test kits that promise a result in 5 minutes for $20. PFAS detection at part-per-trillion levels requires specialized lab instruments (LC-MS/MS); strip-style kits don’t work at these concentrations.

What it costs

Roughly:

Test type	Typical price	Compounds covered
EPA Method 537.1	$200–$350	18 PFAS
EPA Method 533	$250–$400	25 PFAS
Combined 29-PFAS panel	$350–$550	All UCMR 5 compounds

State health departments sometimes offer free or subsidized testing in confirmed contamination zones — worth a phone call before paying out of pocket. The fastest way to find a certified lab is your state’s environmental or health agency website; most maintain a list of accredited labs.

How to take the sample

If the lab mails you a kit (most do), follow their instructions exactly. The general pattern is:

1. Pre-flush. Run the cold tap for 5 minutes from the kitchen faucet (or wherever you usually drink from) to clear stagnant water from the pipes.
2. Use the bottles they sent. Don’t substitute your own — the lab’s bottles are pre-cleaned and may contain a preservative.
3. Don’t smoke, wear waterproof clothing, or use Teflon-thread tape during sampling. All are common PFAS contamination sources that can falsely inflate your reading.
4. Get the bottles back to the lab quickly. Many methods require analysis within ~14 days of sampling.

If a state program is sampling for you, a technician will handle this and follow chain-of-custody procedures.

Reading your results

Lab reports usually look something like this:

Compound	Result	MRL	MCL
PFOA	3.2 ppt	1.7 ppt	4 ppt
PFOS	< 1.7 ppt (ND)	1.7 ppt	4 ppt
PFHxS	6.1 ppt	1.7 ppt	10 ppt
…	…	…	…

A few things to know:

• MRL (Minimum Reporting Limit) is the lowest concentration the lab can reliably measure. “ND” or < MRL means not detected at the level we can detect — not necessarily zero, but below the threshold of meaningful concern.
• MCL is the EPA’s regulatory limit for public water systems. It’s a useful benchmark for private wells too, even though it doesn’t legally apply.
• A single reading slightly above an MCL isn’t the same as long-term exposure at that level. A retest is usually warranted before installing treatment, partly to rule out sampling error.

What to do if levels are above the MCL

Two reasonable paths, often combined:

1. Treat at the point of use. A reverse-osmosis system at the kitchen sink (NSF/ANSI 58 certified for PFOA/PFOS reduction) is the most reliable home option for drinking and cooking water. Whole-house GAC (granular activated carbon) systems work too, but cost more and require periodic media replacement.
2. Treat at the wellhead. A whole-house GAC or anion-exchange system installed near where the well comes into the house treats all water, including showering and laundry. This is more involved (often $3,000–$8,000 installed) and worth the cost mostly when readings are well above the MCL.

If readings are very high — above ~70 ppt for PFOA/PFOS — connecting to a public water main or drilling a new well are options worth discussing with your state environmental agency. Some states have grant or buy-out programs for severely contaminated wells, particularly near known military or industrial sources.

A note on the rest of the household

PFAS exposure from drinking water is the most addressable route for most households, but it isn’t the only one. Cooking with non-stick pans, eating from greaseproof food packaging, and using stain-resistant fabrics all contribute. None of these need to be eliminated overnight; just be aware that filtering your water is one piece of a longer story, not a one-shot fix.

The bottom line

Testing a private well for PFAS costs about as much as a year of lawn fertilizer and gives you a one-time, durable answer about a question that won’t go away on its own. If you live near a known source, have young children, or simply want the data, it’s a reasonable thing to do. If you don’t fit any of those, waiting is also reasonable.

When you do test, use a state-accredited lab running EPA Method 537.1, follow their sampling instructions, and treat the result as the starting point of a decision — not the end of one.

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Sources: EPA Drinking Water Methods, EPA PFAS Strategic Roadmap, state environmental agency lab certification programs, and ATSDR PFAS clinical guidance.