Wilmington, DE Radon Levels

Q: What is the average radon level in Wilmington, DE?

Based on 4 user-submitted tests, the average radon level is 5.50 pCi/L.

Q: What EPA Radon Zone is Wilmington in?

Wilmington is in New Castle County, EPA Zone 2.

Q: How much does radon mitigation cost in Wilmington?

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

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

Wilmington, DE Radon Facts

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

County New Castle County, DE

Zip Code 19801

Avg. User Level 5.50 pCi/L

User Tests 4

Delaware's largest city in New Castle County shows elevated radon levels with an average of 5.5 pCi/L that exceeds the EPA action threshold across multiple zip codes. Positioned within the Philadelphia metro area on Piedmont geology where crystalline bedrock meets coastal plain sediments, Wilmington's varied terrain creates conditions that can produce significant radon concentrations. The city's diverse housing stock, from historic rowhouses to modern developments, requires comprehensive testing given these consistently elevated readings throughout the metropolitan area.

5.50

pCi/L average

Above EPA Action Level

Based on 4 user-submitted radon tests for homes in Wilmington, DE. The EPA recommends taking action at or above 4.0 pCi/L.

4.0 EPA

10+

Wilmington, DE Radon Mitigation

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Wilmington, DE Radon Levels

User-submitted radon test readings from homes in the Wilmington area.

Radon Level	City	Home Age	Foundation
6 pCi/L	Wilmington, DE	51-99 Years	Full Basement
6 pCi/L	Wilmington, DE	21-50 Years	Full Basement
7 pCi/L	Wilmington, DE	51-99 Years	Partial Basement
3 pCi/L	Wilmington, DE	21-50 Years	Full Basement

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Radon FAQ for Wilmington, DE

What is the average radon level in Wilmington, DE?

Based on 4 user-submitted tests, the average radon level in Wilmington is 5.50 pCi/L. This exceeds the EPA's recommended action level of 4.0 pCi/L, and radon testing is recommended for all homes in the area.

What EPA Radon Zone is Wilmington in?

Wilmington and the 19801 zip code are in New Castle 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.

How much does radon mitigation cost in Wilmington?

Radon mitigation in Wilmington 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 Wilmington?

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.

Most Active Radon Markets in Delaware

Cities in Delaware with the most user-submitted radon test data, ranked by number of submissions.

City	Avg User Radon Level	Submissions
Middletown	7.43 pCi/L	7
Wilmington	5.50 pCi/L	4
Lewes	6.00 pCi/L	1
New Castle	4.00 pCi/L	1
Newark	No submissions	0

Wilmington, DE Radon Levels

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

Wilmington, DE Radon Facts

Wilmington, DE Radon Mitigation

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Wilmington, DE Radon Levels

Radon FAQ for Wilmington, DE

Most Active Radon Markets in Delaware

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