Janesville, WI Radon Levels

Q: What EPA Radon Zone is Janesville in?

Janesville is in Rock County, EPA Zone 1.

Q: How much does radon mitigation cost in Janesville?

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

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

Janesville, WI Radon Facts

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

County Rock County, WI

Zip Code 53545

Anchoring the Janesville Metro area in southern Wisconsin's Rock County, the city sits on glacial deposits over dolomite bedrock that can influence radon levels. The community spans multiple zip codes (53545, 53546, 53548) and features diverse housing from historic downtown properties to modern suburban developments, most with full basements typical of Wisconsin construction. Testing data remains limited across the area, but homeowners should conduct radon testing given Wisconsin's high radon potential and prevalent basement construction.

11.50

pCi/L area average

Above EPA Action Level

Rock County average: 11.50 pCi/L, based on 2 user-submitted tests across 1 city in the county. No homeowner readings have been submitted for Janesville 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+

Janesville, WI 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 Janesville?

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

1-800-299-3578 608-318-4941 (local) Toll-free · Mon–Fri 8am–6pm ET

Radon Readings Near Janesville, WI

No homeowner tests have been submitted for Janesville 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
Milton	7.8 mi	11.50 pCi/L	2
Delavan	22.4 mi	6.00 pCi/L	1
Oregon	23.2 mi	12.00 pCi/L	1
Mc Farland	24.8 mi	9.00 pCi/L	1
Elkhorn	26.0 mi	5.00 pCi/L	1
Fontana	27.0 mi	4.50 pCi/L	2
Williams Bay	27.4 mi	12.00 pCi/L	1
Monroe	30.4 mi	13.00 pCi/L	2

Rock County Radon Profile

The bedrock and soils beneath Rock 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 Rock County average 11.50 pCi/L across 2 tests — 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 Rock County.

Radon FAQ for Janesville, WI

What EPA Radon Zone is Janesville in?

Janesville and the 53545 zip code are in Rock 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 Janesville?

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

Radon mitigation in Janesville 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 Janesville?

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.