Washington, MO Radon Mitigation and Testing

Q: What EPA Radon Zone is Washington in?

Washington is in Franklin County, EPA Zone 2.

Q: How much does radon mitigation cost in Washington?

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

Franklin County

EPA Zone 2

Located in Franklin County within the St. Louis Metro area, Washington sits on Mississippian limestone formations that create moderate-to-high radon potential. Testing data for zip code 63090 remains limited, though Missouri's karst geology often produces variable radon levels. The community's housing ranges from historic homes along the Missouri River to newer suburban developments, with basement foundations common throughout the area.

Washington, MO Radon Mitigation

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

Washington, MO Radon Testing

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

Washington Radon Facts

Key details about the radon risk profile for Washington and the 63090 zip code area.

EPA Radon Zone

Zone 2 — Moderate Risk

County

Franklin County, MO

Zip Code

63090

Predicted Screening Level

2–4 pCi/L (Zone 2)

Washington and the 63090 zip code are located in Franklin County, which has an EPA assigned Radon Zone of 2. A radon zone of 2 predicts an average indoor radon screening level between 2 and 4 pCi/L. The EPA recommends testing every home regardless of zone classification.

Radon FAQ for Washington, MO

What EPA Radon Zone is Washington in?

Washington and the 63090 zip code are in Franklin 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 Washington?

Radon mitigation in Washington 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 Washington?

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 Missouri

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

City	Avg User Radon Level	Submissions
Troy	8.50 pCi/L	4
Lees Summit	7.00 pCi/L	3
Columbia	3.00 pCi/L	2
House Springs	7.00 pCi/L	1
Kansas City	7.00 pCi/L	1
Springfield	7.00 pCi/L	1
Independence	5.00 pCi/L	1
Wentzville	No submissions	0