Grimes County, TX radon potential

EPA places Grimes 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. Rank it against the rest of the country and Grimes County lands in the 19th percentile for radon potential.

Where Grimes County sits nationally

Grimes County, Texas is home to about 33,448 people across 787.47 square miles. Population density there runs about 42 people per square mile. Within its own EPA zone, Grimes County is bigger by population than 56% of the counties that share it. EPA's geology-based Region 6 groups Grimes County with 502 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

At Zone 3, Grimes County's predicted county average is under the national indoor average (~1.3 pCi/L) and well below EPA's 4 pCi/L action level — outdoor air nationally runs about 0.4 pCi/L for comparison. Low doesn't mean zero: EPA's own data shows homes in Zone 3 counties like Grimes County testing above the action level often enough that skipping a test isn't the safe assumption.

Testing and mitigation in Grimes 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 Texas's state radon program

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

Where Grimes County's figures come from

Grimes County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Grimes County carries, the zone explainer covers what it does and doesn't tell you about any one house.