Palo Alto County, IA: EPA's radon zone, explained

EPA places Palo Alto County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Palo Alto County in the 74th percentile nationally for radon potential — higher than 74% of the counties EPA has rated.

Where Palo Alto County sits nationally

Palo Alto County, Iowa is home to about 8,809 people across 563.864 square miles. Averaged across its land area, Palo Alto County runs about 16 people per square mile. By population, Palo Alto County is the 800th largest of every county sharing its EPA zone — the 25th percentile by population within that zone. EPA's geology-based Region 7 groups Palo Alto County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Palo Alto 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. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Palo Alto County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Palo Alto County

For a Palo Alto 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 Iowa's state radon program

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

Where Palo Alto County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Palo Alto County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.