Radon zones in Maryland, Delaware and DC
Zone 1: 8, Zone 2: 9, Zone 3: 10. A zone is an area estimate; EPA says all homes should be tested.
- Kent County, Delaware Zone 3
- New Castle County, Delaware Zone 2
- Sussex County, Delaware Zone 3
- District of Columbia Zone 3
- Allegany County, Maryland Zone 2
- Anne Arundel County, Maryland Zone 2
- Baltimore County, Maryland Zone 1
- Calvert County, Maryland Zone 1
- Caroline County, Maryland Zone 3
- Carroll County, Maryland Zone 1
- Cecil County, Maryland Zone 2
- Charles County, Maryland Zone 2
- Dorchester County, Maryland Zone 3
- Frederick County, Maryland Zone 1
- Garrett County, Maryland Zone 2
- Harford County, Maryland Zone 1
- Howard County, Maryland Zone 1
- Kent County, Maryland Zone 3
- Montgomery County, Maryland Zone 1
- Prince George's County, Maryland Zone 2
- Queen Anne's County, Maryland Zone 3
- St. Mary's County, Maryland Zone 2
- Talbot County, Maryland Zone 3
- Washington County, Maryland Zone 1
- Wicomico County, Maryland Zone 3
- Worcester County, Maryland Zone 3
- Baltimore city, Maryland Zone 2
County not listed? See what we left out and why. Leave your email to hear if this data changes.