Radon in Dewey County, South Dakota
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Dewey County is one of 18 South Dakota counties (out of 66) that EPA places in Zone 2. 10 ZIP codes reach into the county, 4 of them entirely.
What the zone means for a Dewey County home
Zone 2 means EPA predicted a county-wide average between 2 and 4 pCi/L. That is below EPA's action level on average, but plenty of individual Dewey County homes will be above 4 pCi/L, and EPA suggests considering a fix between 2 and 4 pCi/L too.
A short-term test kit costs little and takes two to seven days. If your result is 4 pCi/L or higher, EPA recommends a follow-up test and, if it is confirmed, a mitigation system, which typically uses a pipe and fan to pull soil gas from under the foundation and vent it above the roof. Check a result with the level calculator and plan your next step with the follow-up planner.
Finding a radon professional in Dewey County
We have not added South Dakota professionals yet. Until we do, use the South Dakota radon program (SD Dept. of Environment & Natural Resources, 605-773-6038) at danr.sd.gov/Environment/AirQuality/Radon/default.aspx, or the national certification boards: the NRPP pro search and NRSB find a pro. Or ask for free quotes below.
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Get radon quotes from certified pros in Dewey County
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ZIP codes in Dewey County
Open a ZIP to see every county it touches. Where a ZIP crosses a county line, the percentage is the share of its land area inside Dewey County.
South Dakota radon program
EPA lists SD Dept. of Environment & Natural Resources (phone 605-773-6038) as the state contact. State programs can tell you about local test results, discounted kits, disclosure rules for home sales and credentialed professionals. Website: danr.sd.gov/Environment/AirQuality/Radon/default.aspx.
Back to all South Dakota counties.
Frequently asked questions
What is the EPA radon zone for Dewey County, South Dakota?
EPA's Map of Radon Zones puts Dewey County in Zone 2 (moderate potential): Predicted average indoor screening level from 2 to 4 pCi/L.
Do I need to test for radon in Dewey County if the zone is low?
Yes. EPA says the zone map should not be used to decide whether a single home needs testing. Homes with high radon are found in every zone, and neighboring homes can test very differently. Testing is cheap and the only way to know your level.
How do I find a certified radon professional in Dewey County?
Ask the South Dakota radon program (SD Dept. of Environment & Natural Resources, 605-773-6038) for its list of credentialed professionals, or search the national certification boards, NRPP and NRSB. You can also ask for free quotes with the form on this page.
How many ZIP codes are in Dewey County?
10 ZIP codes have at least part of their land area in Dewey County, based on the U.S. Census Bureau's 2020 ZIP Code Tabulation Area to county relationship file.
Free checklist · PDF
Radon Test Checklist
A one-page, step-by-step checklist for running a home radon test right the first time, and what to do with the number.
- Short-term vs. long-term test: which to use
- Closed-house conditions and where to place the kit
- What 2, 4 and 8 pCi/L mean and when to fix
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