Thornton, CO Radon Levels

Q: What EPA Radon Zone is Thornton in?

Thornton is in Adams County, EPA Zone 1.

Q: How much does radon mitigation cost in Thornton?

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

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

Thornton, CO Radon Facts

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

County Adams County, CO

Zip Code 80241

Situated in Adams County as part of the Denver Metro area, Thornton lies over sedimentary formations and prairie soils that can produce variable radon conditions. The city's suburban neighborhoods feature predominantly single-family homes built from the 1970s onward, many with full basements where radon can accumulate. Limited testing data is currently available for zip code 80241, making professional radon testing especially important for homeowners in this EPA Zone 1 area.

8.00

pCi/L area average

Above EPA Action Level

Adams County average: 8.00 pCi/L, based on 8 user-submitted tests across 4 cities in the county. No homeowner readings have been submitted for Thornton 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+

Thornton, CO 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 Thornton, CO

No homeowner tests have been submitted for Thornton 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
Commerce City	4.3 mi	9.00 pCi/L	1
Broomfield	6.2 mi	5.00 pCi/L	1
Arvada	8.0 mi	5.00 pCi/L	2
Denver	9.0 mi	6.22 pCi/L	9
Brighton	9.8 mi	6.00 pCi/L	2
Lafayette	11.1 mi	8.00 pCi/L	2
Erie	14.2 mi	20.00 pCi/L	1
Aurora	16.3 mi	7.40 pCi/L	5

Adams County Radon Profile

Adams County falls in EPA Radon Zone 1, meaning the local uranium-bearing geology is predicted to drive average indoor radon screening levels above the EPA's 4 pCi/L action threshold. Homeowner-submitted tests from 4 cities in Adams County average 8.00 pCi/L across 8 tests — above the EPA's 4 pCi/L action level, reinforcing the need for testing across the county. Since radon is the second leading cause of lung cancer nationally, the EPA urges every household in Adams County to test, as levels can differ between neighboring homes.

Radon FAQ for Thornton, CO

What EPA Radon Zone is Thornton in?

Thornton and the 80241 zip code are in Adams 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 Thornton?

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

Radon mitigation in Thornton 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 Thornton?

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.