What EPA's radon map says about San Benito County

San Benito 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. That puts San Benito County in the 57th percentile nationally for radon potential — higher than 57% of the counties EPA has rated.

How San Benito County compares

About 69,159 people live in San Benito County, California, spread over 1,388.652 square miles. Averaged across its land area, San Benito County runs about 50 people per square mile. Among counties sharing San Benito County's EPA zone, it outranks 74% of them by population. EPA's geology-based Region 9 groups San Benito County with 94 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

San Benito 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). A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in San Benito County — testing is the only way to know an individual home's actual level.

Testing and mitigation in San Benito County

Mitigation cost doesn't depend on San Benito County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find California's state radon program

San Benito County's test kit answers today; a Airthings radon monitor keeps answering for San Benito County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

More on how this number was built

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