Williamstown, MO Radon Levels

Q: What EPA Radon Zone is Williamstown in?

Williamstown is in Lewis County, EPA Zone 2.

Q: How much does radon mitigation cost in Williamstown?

Radon mitigation typically costs between $800 and $2,000. Most standard systems fall in the $1,000-$1,500 range.

Check local Williamstown radon levels and find certified testing and mitigation professionals to keep your home safe

Williamstown, MO Radon Facts

EPA Radon Zone Zone 2 — Moderate Risk 2–4 pCi/L (Zone 2)

County Lewis County, MO

Zip Code 63473

Situated in Lewis County in northeastern Missouri, Williamstown sits atop glacial deposits and limestone formations that can facilitate radon gas movement. Testing data for the 63473 area is currently insufficient, making professional radon assessment essential for homeowners. The region's agricultural character often features older homes with basements or crawl spaces where radon can concentrate.

6.67

pCi/L area average

Above EPA Action Level

Nearby homeowner readings average 6.67 pCi/L, based on 3 tests from 2 nearby cities. No readings have been submitted for Williamstown yet, so the closest recorded data is shown as a benchmark. The EPA recommends taking action at or above 4.0 pCi/L.

4.0 EPA

10+

Williamstown, MO Radon Mitigation

Professional radon mitigation is the most effective way to permanently lower radon levels and protect your household.

Need Radon Mitigation or Testing in Williamstown?

100% Free, No-Obligation Quotes
Matches You with State-Licensed Lewis County Pros

1-800-299-3578 636-205-4618 (local) Toll-free · Mon–Fri 8am–6pm ET

Radon Readings Near Williamstown, MO

No homeowner tests have been submitted for Williamstown yet. The closest cities with user-submitted radon data are shown below — explore them to gauge local conditions. Radon varies by home, so testing is the only way to know your level.

City	Distance	Avg User Level	Readings
Palmyra	34.3 mi	8.00 pCi/L	1
Hannibal	43.1 mi	6.00 pCi/L	2

Lewis County Radon Profile

The soils and bedrock of Lewis County place it in EPA Radon Zone 2, a moderate-risk classification with predicted indoor averages of 2 to 4 pCi/L. Few homeowner tests have been logged inside Lewis County so far, which is why this page draws on the nearest recorded readings to illustrate regional radon levels. Since radon is the second leading cause of lung cancer nationally, the EPA urges every household in Lewis County to test, as levels can differ between neighboring homes.

Radon FAQ for Williamstown, MO

What EPA Radon Zone is Williamstown in?

Williamstown and the 63473 zip code are in Lewis County, which has an EPA assigned Radon Zone of 2. A zone of 2 predicts an average indoor radon screening level between 2 and 4 pCi/L.

Why are radon readings shown from areas near Williamstown?

No homeowner radon tests have been submitted for Williamstown yet. Because radon is driven by regional soil and bedrock geology, readings from the closest cities—and the Lewis County average—are the best available indicator of local conditions until Williamstown homeowners submit their own results. The EPA still recommends testing every individual home, since levels can vary significantly from house to house.

How much does radon mitigation cost in Williamstown?

Radon mitigation in Williamstown typically costs between $800 and $2,000. Most homes with standard basements can be mitigated with a sub-slab depressurization system in the $1,000–$1,500 range. Factors that can increase cost include complex foundations, crawl spaces, or very high radon levels.

Should I test for radon if I'm buying a home in Williamstown?

Yes. Radon testing should be part of every home purchase. A short-term radon test is typically included as part of the home inspection process and costs $150–$250. If elevated levels are found, you can negotiate mitigation as part of the sale.