Walworth County, SD: Radon Risk Data
EPA predicts average indoor levels above 4 pCi/L · Source: EPA, CDC
Tipper's take on Walworth County
Walworth County is in EPA Zone 1, the highest risk classification. The EPA's geological and indoor measurement data predicts average indoor radon levels above 4 pCi/L here, which is the agency's action level. CDC testing data from Walworth County puts the average measured radon level at 7.5 pCi/L.
Zone 1 doesn't mean every home is over the limit. Radon varies house to house depending on foundation type, construction, soil, and ventilation. A well-sealed Zone 1 home might test at 2 pCi/L. A cracked basement in a Zone 3 county might test at 9 pCi/L. The zone tells you about area-level risk. Your test result tells you about your home.
Zone 1 is a meaningful signal, though. If you live in Walworth County and haven't tested, you should. A basic test kit runs about $15 and gives you a result in 48 hours.
Sources: EPA Radon Zone Map, CDC Environmental Public Health Tracking Network
Test Your Home
The only way to know your home's radon level is to test it. Tipper recommends starting with a short-term test kit. It includes the lab fee, takes 48 hours, and costs about $15.
Radon Professionals Serving South Dakota
We don't have contractor listings for this area yet.
The EPA maintains a national directory of certified radon professionals.
How Walworth County Compares
vs. South Dakota Statewide
Walworth County's average of 7.5 pCi/L is 1.2 pCi/L below the statewide average.
Frequently Asked Questions: Walworth County
My home is in Zone 1. Does that mean it's definitely dangerous?
Not automatically. Zone 1 means the EPA expects area-wide average indoor levels above 4 pCi/L. That's an average across many homes with different foundations, construction types, and ventilation. A well-sealed Zone 1 home on a concrete slab might test at 1.5 pCi/L. Test first, then decide. The zone tells you to take it seriously. Your test result tells you what to do.
What is the EPA's action level, and why 4 pCi/L?
The EPA recommends fixing your home if it tests at or above 4 pCi/L (picocuries per liter). There's no completely safe level. Radon exposure is a spectrum. But 4 pCi/L is where the EPA concludes mitigation is clearly cost-effective. The WHO sets a lower reference level of 2.7 pCi/L. If your home is between 2 and 4 pCi/L, mitigation is optional but worth considering, especially in bedrooms.
How often should I retest for radon?
If your home tested below 4 pCi/L and nothing major has changed structurally, retesting every two years is a good habit. Retest immediately after any significant basement renovation, after buying or selling a home, or after installing a mitigation system (to confirm it's working). Radon levels can shift as foundations settle and conditions change.
The county average is above 4 pCi/L. Should I be worried about my kids?
Children's lungs are still developing, and they typically spend more time at home, so radon exposure matters for them. The county average above 4 pCi/L doesn't mean your home is above that level, though. Test your specific home. If it comes back high, a mitigation system typically brings levels below 2 pCi/L. That's the right response.