Portsmouth city, VA: EPA's radon zone, explained

EPA's own radon map rates Portsmouth city zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Nationally, Portsmouth city ranks higher in radon potential than 26% of rated counties (the 26th percentile).

How Portsmouth city compares

Portsmouth city, Virginia is home to about 96,482 people across 33.301 square miles. That works out to roughly 2,897 people per square mile. By population, Portsmouth city is the 223rd largest of every county sharing its EPA zone — the 78th percentile by population within that zone.

Why the zone isn't the answer by itself

Well clear of both the 1.3 pCi/L national indoor average and EPA's 4 pCi/L action level, Portsmouth city's Zone 3 prediction is the low end of the scale. A Zone 3 label describes Portsmouth city's average, not any one basement or slab in it — testing is still the only way an individual homeowner actually finds out.

Next steps for a home in Portsmouth city

For a Portsmouth 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 Virginia's state radon program

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

Where Portsmouth city's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.