Radon in ZIP code 21758
Last updated
ZIP 21758 crosses 2 county lines. Most of its land (50.3%) is in Frederick County, Maryland. EPA’s radon zone for this area: Zone 1, highest potential.
Predicted average indoor screening level above 4 pCi/L.
Predicted average indoor screening level above 4 pCi/L.
What this means for homes in 21758
EPA built its zone map county by county in 1993, so every address in each part of 21758 shares its county’s prediction. The zone is a starting point, not a measurement of your house. Zone 1 areas like this one have a high share of homes above 4 pCi/L, so testing is a priority.
Because 21758 crosses county lines, your county depends on your street. Your property tax bill or county assessor site shows which county you are in. Next: read how to test your home, then check the number with the level calculator.
Free, no obligation
Get radon quotes from certified pros in ZIP 21758
Tell us what you need and we will try to connect you with up to three state-certified or licensed radon professionals who work in your area. It is free and there is no obligation.
We only share your request with radon professionals for this job. We do not sell your details to anyone else. Radon by ZIP may be paid by professionals for leads or featured placement.
Nearby ZIP codes in Frederick County
Maryland radon help
The Maryland radon program (410-537-3193) can help with test kits, local data and credentialed professionals: health.maryland.gov/phpa/OEHFP/EH/pages/radon.aspx.
Frequently asked questions
What is the radon zone for ZIP code 21758?
ZIP 21758 spans 2 counties. The highest-potential zone among them is Zone 1 (highest potential). Frederick County: Zone 1 (50.3% of the ZIP's land); Washington County: Zone 1 (49.7% of the ZIP's land).
Should I test for radon in 21758?
Yes. EPA recommends testing every home regardless of zone, because radon varies from house to house. Fix the home if a confirmed result is 4 pCi/L or higher, and consider fixing between 2 and 4 pCi/L.
Free checklist · PDF
Radon Test Checklist
A one-page, step-by-step checklist for running a home radon test right the first time, and what to do with the number.
- Short-term vs. long-term test: which to use
- Closed-house conditions and where to place the kit
- What 2, 4 and 8 pCi/L mean and when to fix
Free. We email you the download link, plus an occasional plain-English guide. Unsubscribe any time. We never sell your email. Privacy