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Radon Levels, Testing and Mitigation in South Dakota

South Dakota has 65 counties, with 47 classified as EPA Zone 1 (highest risk). With an average radon level of 10.26 pCi/L, South Dakota state testing data reveals significantly elevated risks across multiple counties. Testing is highly recommended.

South Dakota is the 17th most expansive state in terms of size but the 5th least populous. It also happens to be the 5th least densely populated state in the entire US.

South Dakota does have an active radon program, dedicated to educating citizens about the risks associated with the deadly gas. You can find more information on Radon, testing and mitigation at the official page.

10.26
Avg. pCi/L
65
Counties
47
Zone 1 Counties

South Dakota Radon Map

South Dakota radon levels by county
Zone 1 — High
Zone 2 — Moderate
Zone 3 — Low

South Dakota Metro Areas

Explore radon data organized by metro region, including average levels, hotspot cities, and local mitigation professionals.

Rapid City Metro
5 cities
Sioux Falls Metro
5 cities

Most Active Radon Markets in South Dakota

Cities with the most user-submitted radon test data, ranked by number of submissions.

CityAvg User Radon LevelSubmissions
Spearfish 7.75 pCi/L 4
Rapid City 10.50 pCi/L 2
Aberdeen 8.50 pCi/L 2
Sioux Falls 6.00 pCi/L 2
Watertown 6.00 pCi/L 2

South Dakota Counties by EPA Radon Zone

All 65 South Dakota counties with their EPA radon zone classification and user-submitted average radon levels.

Zone 1 — High Risk
Predicted avg. indoor levels > 4.0 pCi/L
Zone 1 47 counties
Aurora County Zone 1
Avg:
Beadle County Zone 1
Avg: 12.0 pCi/L
Bon Homme County Zone 1
Avg:
Brookings County Zone 1
Avg: 9.0 pCi/L
Brown County Zone 1
Avg: 8.5 pCi/L
Brule County Zone 1
Avg:
Buffalo County Zone 1
Avg:
Campbell County Zone 1
Avg:
Charles Mix County Zone 1
Avg:
Clark County Zone 1
Avg:
Clay County Zone 1
Avg: 13.0 pCi/L
Codington County Zone 1
Avg: 6.0 pCi/L
Corson County Zone 1
Avg: 6.0 pCi/L
Davison County Zone 1
Avg:
Day County Zone 1
Avg: 20.0 pCi/L
Deuel County Zone 1
Avg:
Douglas County Zone 1
Avg: 7.0 pCi/L
Edmunds County Zone 1
Avg:
Faulk County Zone 1
Avg:
Grant County Zone 1
Avg: 10.0 pCi/L
Hamlin County Zone 1
Avg:
Hand County Zone 1
Avg:
Hanson County Zone 1
Avg:
Hughes County Zone 1
Avg:
Hutchinson County Zone 1
Avg:
Hyde County Zone 1
Avg:
Jerauld County Zone 1
Avg:
Kingsbury County Zone 1
Avg:
Lake County Zone 1
Avg: 6.0 pCi/L
Lincoln County Zone 1
Avg: 5.5 pCi/L
Lyman County Zone 1
Avg:
Marshall County Zone 1
Avg:
McCook County Zone 1
Avg:
McPherson County Zone 1
Avg:
Miner County Zone 1
Avg:
Minnehaha County Zone 1
Avg: 11.7 pCi/L
Moody County Zone 1
Avg: 6.0 pCi/L
Perkins County Zone 1
Avg:
Potter County Zone 1
Avg:
Roberts County Zone 1
Avg:
Sanborn County Zone 1
Avg:
Spink County Zone 1
Avg:
Stanley County Zone 1
Avg: 20.0 pCi/L
Sully County Zone 1
Avg:
Turner County Zone 1
Avg:
Union County Zone 1
Avg: 11.0 pCi/L
Walworth County Zone 1
Avg:
Zone 2 — Moderate Risk
Predicted avg. indoor levels 2–4 pCi/L
Zone 2 18 counties
Bennett County Zone 2
Avg:
Butte County Zone 2
Avg: 20.0 pCi/L
Custer County Zone 2
Avg: 20.0 pCi/L
Dewey County Zone 2
Avg:
Fall River County Zone 2
Avg: 8.0 pCi/L
Gregory County Zone 2
Avg:
Haakon County Zone 2
Avg:
Harding County Zone 2
Avg:
Jackson County Zone 2
Avg:
Jones County Zone 2
Avg:
Lawrence County Zone 2
Avg: 8.2 pCi/L
Meade County Zone 2
Avg:
Mellette County Zone 2
Avg:
Pennington County Zone 2
Avg: 10.5 pCi/L
Shannon County Zone 2
Avg:
Todd County Zone 2
Avg:
Tripp County Zone 2
Avg:
Ziebach County Zone 2
Avg:

South Dakota Cities & Towns

Browse radon data for individual cities across South Dakota. Each city page includes user-submitted radon levels, local contractors, and mitigation resources.

Aberdeen Agar Alcester Alexandria Allen Alpena Amherst Andover Arlington Armour Artesian Ashton Astoria Aurora Avon Baltic Batesland Bath Belle Fourche Belvidere Beresford Big Stone City Bison Black Hawk Blunt Bonesteel Bowdle Box Elder Bradley Brandon Brandt Bridgewater Bristol Britton Brookings Bruce Bryant Buffalo Buffalo Gap Burbank Burke Camp Crook Canistota Canova Canton Caputa Carpenter Carthage Castlewood Cavour Centerville Chamberlain Chancellor Chester Claire City Claremont Clark Clear Lake Colman Colome Colton Columbia Conde Corona Corsica Cresbard Crooks Custer Dallas Dante Davis De Smet Deadwood Dell Rapids Delmont Dimock Doland Draper Dupree Eagle Butte Eden Edgemont Egan Elk Point Elkton Ellsworth Afb Emery Enning Erwin Estelline Ethan Eureka Fairburn Fairfax Fairview Faith Faulkton Fedora Flandreau Florence Fort Pierre Fort Thompson Frankfort Frederick Freeman Fulton Gann Valley Garden City Garretson Gary Gayville Geddes Gettysburg Glencross Glenham Goodwin Gregory Grenville Groton Hamill Harrisburg Harrison Harrold Hartford Hayes Hayti Hazel Hecla Henry Hermosa Herreid Herrick Highmore Hill City Hitchcock Holabird Hosmer Hot Springs Houghton Hoven Howard Howes Hudson Humboldt Hurley Huron Ideal Interior Ipswich Irene Iroquois Isabel Java Jefferson Kadoka Keldron Kennebec Keystone Kimball Kyle Labolt Lake Andes Lake City Lake Norden Lake Preston Langford Lead Lebanon Lemmon Lennox Leola Lesterville Letcher Lodgepole Long Lake Long Valley Lower Brule Ludlow Madison Mansfield Marion Martin Marvin Mc Intosh Mc Laughlin Meadow Mellette Menno Midland Milbank Milesville Miller Mission Mission Hill Mitchell Mobridge Monroe Montrose Morristown Mound City Mount Vernon Mud Butte Murdo Nemo New Effington New Holland New Underwood Newell Nisland Norris North Sioux City Northville Nunda Oacoma Oelrichs Oglala Okaton Oldham Olivet Onaka Onida Oral Orient Ortley Owanka Parker Parkston Parmelee Peever Philip Piedmont Pierpont Pierre Pine Ridge Plankinton Platte Pollock Porcupine Prairie City Presho Pukwana Quinn Ralph Ramona Rapid City Raymond Redfield Ree Heights Reliance Renner Reva Revillo Ridgeview Rockham Roscoe Rosholt Roslyn Rowena Rutland Saint Charles Saint Francis Saint Lawrence Saint Onge Salem Scenic Scotland Selby Seneca Sioux Falls Sisseton South Shore Spearfish Spencer Springfield Stephan Stickney Stockholm Strandburg Stratford Sturgis Summit Tabor Tea Timber Lake Tolstoy Toronto Trail City Trent Tripp Tulare Turton Tuthill Twin Brooks Tyndall Union Center Utica Vale Valley Springs Veblen Vermillion Viborg Vienna Virgil Vivian Volga Volin Wagner Wakonda Wakpala Walker Wall Wallace Wanblee Warner Wasta Watauga Watertown Waubay Webster Wentworth Wessington Wessington Springs Westport White White Lake White Owl White River Whitewood Willow Lake Wilmot Winfred Winner Witten Wolsey Wood Woonsocket Worthing Wounded Knee Yale Yankton

Frequently Asked Questions About Radon in South Dakota

What radon level is considered "high"?
The EPA action level is 4.0 pCi/L — many homeowners also choose to fix levels between 2.0 and 4.0 pCi/L. Any home with levels at or above 4.0 pCi/L should be mitigated.
How much does radon mitigation cost in South Dakota?
Radon mitigation typically costs between $800 and $2,500, depending on foundation type and radon severity. A standard sub-slab depressurization system usually falls in the $1,000–$1,500 range.
Does mitigation actually work?
Yes — properly installed systems typically reduce radon levels by up to 99%. A post-mitigation test confirms the system is working correctly, and many homeowners re-test periodically.
Should I test again after mitigation?
Yes. A post-mitigation test is the proof your system is working. The EPA recommends testing within 30 days of installation and retesting every two years.
What EPA Radon Zone is my South Dakota county in?
South Dakota counties are classified into three EPA Radon Zones. Zone 1 (highest risk, >4 pCi/L) indicates the most concern. Zone 2 (moderate, 2–4 pCi/L) and Zone 3 (lowest, <2 pCi/L) round out the classification. Use the county directory above to find your specific county's zone and data.

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