Williamsfield, IL Radon Levels

Q: What EPA Radon Zone is Williamsfield in?

Williamsfield is in Knox County, EPA Zone 1.

Q: How much does radon mitigation cost in Williamsfield?

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

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

Williamsfield, IL Radon Facts

EPA Radon Zone Zone 1 — High Risk > 4.0 pCi/L (Zone 1)

County Knox County, IL

Zip Code 61489

Situated in Knox County, Williamsfield experiences the geological conditions typical of western Illinois, where glacial deposits over limestone bedrock can facilitate radon accumulation. Testing data for the 61489 area remains sparse, emphasizing the importance of individual home testing. Rural properties in the Peoria Metro region often feature older homes with basements that may concentrate radon gas.

8.00

pCi/L area average

Above EPA Action Level

Knox County average: 8.00 pCi/L, based on 1 user-submitted test across 1 city in the county. No homeowner readings have been submitted for Williamsfield itself yet, so this county figure is the closest available benchmark. The EPA recommends taking action at or above 4.0 pCi/L.

4.0 EPA

10+

Williamsfield, IL Radon Mitigation

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

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Radon Readings Near Williamsfield, IL

No homeowner tests have been submitted for Williamsfield 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
Knoxville	13.6 mi	8.00 pCi/L	1
Dunlap	21.0 mi	7.00 pCi/L	1
Kewanee	22.3 mi	8.00 pCi/L	1
Peoria	26.1 mi	5.00 pCi/L	1
Mapleton	27.1 mi	8.00 pCi/L	1
New Windsor	29.3 mi	6.00 pCi/L	1
East Peoria	30.5 mi	8.00 pCi/L	3
Cuba	30.7 mi	6.00 pCi/L	1

Knox County Radon Profile

The bedrock and soils beneath Knox County are classified by the EPA as Radon Zone 1, the highest-risk tier, with predicted average indoor screening levels above 4 pCi/L. Homeowner-submitted tests from 1 city in Knox County average 8.00 pCi/L across 1 test — above the EPA's 4 pCi/L action level, reinforcing the need for testing across the county. Radon is the second leading cause of lung cancer in the United States, and a short-term test is the only way to confirm a specific home's level in Knox County.

Radon FAQ for Williamsfield, IL

What EPA Radon Zone is Williamsfield in?

Williamsfield and the 61489 zip code are in Knox County, which has an EPA assigned Radon Zone of 1. A zone of 1 predicts an average indoor radon screening level greater than 4 pCi/L.

Why are radon readings shown from areas near Williamsfield?

No homeowner radon tests have been submitted for Williamsfield yet. Because radon is driven by regional soil and bedrock geology, readings from the closest cities—and the Knox County average—are the best available indicator of local conditions until Williamsfield 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 Williamsfield?

Radon mitigation in Williamsfield 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 Williamsfield?

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.