Richmond County, NY: EPA's radon zone, explained

EPA places Richmond County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Richmond County in the 31st percentile nationally for radon potential — higher than 31% of the counties EPA has rated.

Richmond County by the numbers

Richmond County, New York is home to about 498,212 people across 57.523 square miles. Averaged across its land area, Richmond County runs about 8,661 people per square mile. By population, Richmond County is the 50th largest of every county sharing its EPA zone — the 95th percentile by population within that zone. Richmond County falls in EPA Radon Region 2, one of 83 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Well clear of both the 1.3 pCi/L national indoor average and EPA's 4 pCi/L action level, Richmond County's Zone 3 prediction is the low end of the scale. A Zone 3 rating means Richmond County's county-wide average is predicted low, but EPA is explicit that a meaningful share of homes in low-potential zones still test above the action level — a low zone is not a reason to skip testing.

Next steps for a home in Richmond County

For a Richmond County 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 New York's state radon program

For Richmond County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Richmond 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 Richmond County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Richmond County's numbers. Whatever zone Richmond County carries, the zone explainer covers what it does and doesn't tell you about any one house.