Cumberland County, ME radon potential

Cumberland County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally that's the 98th percentile for radon potential — Cumberland County outranks 98% of every county EPA has rated.

Cumberland County by the numbers

Cumberland County, Maine is home to about 313,809 people across 836.231 square miles. That works out to roughly 375 people per square mile. Within its own EPA zone, Cumberland County is bigger by population than 93% of the counties that share it. Geologically, Cumberland County is grouped into EPA Region 1 alongside 58 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

Cumberland County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. Being in Zone 1 raises the odds Cumberland County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

Next steps for a home in Cumberland County

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Maine's state radon program

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

Where Cumberland County's figures come from

Cumberland County'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.