Greenwich, CT Radon Mitigation and Testing

Q: What is the average radon level in Greenwich, CT?

Based on 3 user-submitted tests, the average radon level is 7.70 pCi/L.

Q: What EPA Radon Zone is Greenwich in?

Greenwich is in Fairfield County, EPA Zone 1.

Q: How much does radon mitigation cost in Greenwich?

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

Avg: 7.70 pCi/L

Fairfield County

EPA Zone 1

3 user tests

Greenwich is located in Fairfield County, Connecticut. With 3 user-submitted readings averaging 7.70 pCi/L, the area exceeds the EPA's 4.0 pCi/L action threshold, and testing is strongly recommended for homeowners in the 06830 zip code.

7.70

pCi/L average

Above EPA Action Level

Based on 3 user-submitted radon tests for homes in Greenwich, CT. The EPA recommends taking action at or above 4.0 pCi/L.

4.0 EPA

10+

Greenwich, CT Radon Mitigation

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

Greenwich, CT Radon Testing

Finding qualified radon testing professionals is the first step toward protecting your home.

Greenwich, Connecticut Radon Levels

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

Radon Level	City	Home Age	Foundation	Submitted
15 pCi/L	Greenwich, CT	21-50 Years	Full Basement	Mar 2025
4 pCi/L	Greenwich, CT	0-20 Years	—	May 2019

Have a radon test result for Greenwich? Submit your reading to help other homeowners.

Greenwich Radon Facts

Key details about the radon risk profile for Greenwich and the 06830 zip code area.

EPA Radon Zone

Zone 1 — High Risk

County

Fairfield County, CT

Zip Code

06830

Predicted Screening Level

> 4.0 pCi/L (Zone 1)

Avg. User Submitted Level

7.70 pCi/L

User Tests Submitted

Greenwich and the 06830 zip code are located in Fairfield County, which has an EPA assigned Radon Zone of 1. A radon zone of 1 predicts an average indoor radon screening level greater than 4 pCi/L. The EPA recommends testing every home regardless of zone classification.

Radon FAQ for Greenwich, CT

What is the average radon level in Greenwich, CT?

Based on 3 user-submitted tests, the average radon level in Greenwich is 7.70 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 Greenwich in?

Greenwich and the 06830 zip code are in Fairfield 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.

How much does radon mitigation cost in Greenwich?

Radon mitigation in Greenwich 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 Greenwich?

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 Connecticut

Cities with the most user-submitted radon test data in the state.

City	Avg User Radon Level	Submissions
Hamden	4.75 pCi/L	4
West Hartford	4.25 pCi/L	4
Greenwich	7.67 pCi/L	3
Norwalk	7.00 pCi/L	1
Stamford	5.00 pCi/L	1
Middletown	4.00 pCi/L	1
Guilford	No submissions	0
Ridgefield	No submissions	0