Arlington County, VA radon potential

Arlington County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. Nationally, Arlington County ranks higher in radon potential than 63% of rated counties (the 63rd percentile).

How Arlington County compares

Arlington County, Virginia is home to about 239,807 people across 25.997 square miles. Averaged across its land area, Arlington County runs about 9,224 people per square mile. Within its own EPA zone, Arlington County is bigger by population than 90% of the counties that share it. EPA's geology-based Region 3 groups Arlington County with 244 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Arlington County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). Nothing about a Zone 2 label lowers the case for testing in Arlington County — EPA recommends it in every zone, moderate included.

Testing and mitigation in Arlington 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 Virginia's state radon program

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

Where Arlington County's figures come from

Arlington County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.