Baltimore city, MD: EPA's radon zone, explained

EPA's own radon map rates Baltimore city zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Baltimore city sits at the 65th percentile nationally for radon potential — above 65 of every 100 rated counties.

How Baltimore city compares

Baltimore city, Maryland is home to about 568,271 people across 80.946 square miles. Population density there runs about 7,020 people per square mile. By population, Baltimore city is the 43rd largest of every county sharing its EPA zone — the 96th percentile by population within that zone. EPA's geology-based Region 3 groups Baltimore city with 244 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Baltimore city

EPA's Zone 2 rating for Baltimore city sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Nothing about a Zone 2 label lowers the case for testing in Baltimore city — EPA recommends it in every zone, moderate included.

Next steps for a home in Baltimore city

For a Baltimore city homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Maryland's state radon program

For Baltimore city, an ongoing number beats a one-time test - a Airthings radon monitor tracks Baltimore city's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

Where Baltimore city's figures come from

Baltimore city's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.