Tag: Property Damage

Wyoming has significant radon risk, with an estimated 50% of Wyoming homes testing above the EPA action level of 4.0 pCi/L. Wyoming’s geology — including uranium-bearing sandstone formations that once fueled a major uranium mining industry, granite in the Laramie and Wind River ranges, and sedimentary formations throughout the basin areas — creates high radon potential across much of the state. Wyoming has limited specific radon regulation but relies on EPA guidance and national certification standards.

EPA Radon Zone Designation

Most Wyoming counties are Zone 1 or Zone 2. The highest-radon areas include the Wyoming uranium belt counties of south-central Wyoming (Carbon, Fremont, Natrona, and Converse counties), the Laramie area (Albany County), and the Casper area (Natrona County). The northeastern Wyoming counties including Weston and Niobrara counties also show elevated radon due to uranium-bearing geology. Even the lower-elevation basin counties show significant radon levels due to uranium-rich sedimentary formations.

Radon Contractor Requirements in Wyoming

Wyoming does not have a state radon contractor licensing statute. Wyoming relies on NRPP and NRSB national certification as the operative credential for radon professionals. The Wyoming Department of Environmental Quality administers radon program resources. For certified radon professionals in Wyoming, search the NRPP directory at nrpp.info or the NRSB directory at nrsb.org by location.

Radon Disclosure Requirements in Wyoming

Wyoming does not have a radon-specific real estate disclosure statute. The Wyoming Seller’s Real Property Disclosure Act requires disclosure of known material defects — and known elevated radon test results are material information that sellers should disclose. Real estate agents in Wyoming’s high-radon areas recommend radon testing as standard practice during the inspection period.

Frequently Asked Questions

Why is Wyoming a high-radon state?

Wyoming sits on extensive uranium-bearing geological formations — the same uranium deposits that made Wyoming a major uranium mining state historically. These uranium-rich sandstones and sedimentary rocks produce significant radon across much of the state, particularly in south-central and northeastern Wyoming.

Does Wyoming require radon contractor licensing?

Wyoming has no state radon contractor licensing statute. NRPP or NRSB national certification is the operative credential. Search the NRPP directory at nrpp.info for certified Wyoming contractors.

What Wyoming counties have the highest radon?

South-central Wyoming counties in the uranium belt — Carbon, Fremont, Natrona, and Converse counties — have the highest radon potential. Albany County (Laramie) and northeastern Wyoming counties including Weston and Niobrara also show elevated levels.

Wyoming Uranium Belt and Radon History

Wyoming’s uranium belt — stretching across south-central Wyoming through Carbon, Fremont, Natrona, Converse, and Campbell counties — was one of the most productive uranium mining regions in the U.S. during the mid-20th century. The same uranium-bearing sandstone formations that made Wyoming a mining powerhouse are directly responsible for the state’s elevated radon levels. Even in areas without active or historical mining, the underlying geology produces radon at rates that make testing essential for all Wyoming homeowners.

Radon in Casper and Cheyenne

Natrona County (Casper) sits directly over uranium-bearing geological formations and is among Wyoming’s highest-radon areas. Laramie County (Cheyenne) in southeastern Wyoming shows elevated levels due to both geological factors and proximity to the front range geology. The University of Wyoming in Albany County (Laramie) is in a Zone 1 area. Jackson Hole (Teton County) in northwestern Wyoming shows elevated radon from the Teton Range granitic geology. Essentially no county in Wyoming is low-risk.

Radon and Wyoming Real Estate Transactions

While Wyoming lacks a radon-specific disclosure statute, radon is increasingly standard in Wyoming real estate transactions — particularly in Casper, Cheyenne, and the resort markets of Jackson Hole and Cody. Many Wyoming real estate contracts include radon contingencies by custom and buyer demand, even without a statutory requirement. Buyers in Wyoming should always request radon testing during the inspection period and include a contingency at 4.0 pCi/L or lower in their offer.

Nebraska has some of the highest radon levels in the central United States. The Nebraska Department of Health and Human Services estimates that approximately 55% of Nebraska homes have radon levels above 4.0 pCi/L, and Nebraska’s statewide average is among the top five in the nation. Nebraska’s geology — including Cretaceous chalk and shale formations, Pleistocene glacial deposits in the eastern half, and uranium-bearing geological units throughout — creates high radon potential statewide.

EPA Radon Zone Designation

Most Nebraska counties are Zone 1. All counties in Nebraska’s eastern glaciated region are Zone 1 (Douglas, Sarpy, Lancaster, Cass, Otoe, and other eastern counties), as are the central Sandhills counties and western Nebraska counties overlying chalk formations. The panhandle counties of extreme western Nebraska have somewhat lower but still significant radon potential.

Radon Contractor Requirements in Nebraska

Nebraska requires radon professionals to hold NRPP or NRSB national certification to legally perform radon measurement and mitigation services. Nebraska’s radon program is administered through the Nebraska Department of Health and Human Services. Nebraska does not have a separate state radon contractor licensing statute — national certification is the operative credential. Verify credentials at nrpp.info or nrsb.org before hiring any radon professional.

Radon Disclosure Requirements in Nebraska

Nebraska’s Seller Property Disclosure Act requires sellers to disclose known material defects. Nebraska does not have a radon-specific disclosure statute, but the general material defect obligation covers known elevated radon. The Nebraska Real Estate Commission provides guidance on radon as a potential disclosure item. Radon testing is recommended in all Nebraska real estate transactions given the state’s high prevalence.

Frequently Asked Questions

How high is radon in Nebraska?

Nebraska has one of the nation’s highest average indoor radon concentrations, with approximately 55% of homes above the EPA action level of 4.0 pCi/L. Most Nebraska counties are Zone 1.

Does Nebraska require radon contractor certification?

NRPP or NRSB national certification is the operative requirement. No separate Nebraska licensing statute exists. Verify credentials at nrpp.info or nrsb.org before hiring.

Should I test for radon before buying a home in Nebraska?

Yes — emphatically. With 55% of Nebraska homes above the EPA action level, radon testing should be a standard contingency in every Nebraska real estate transaction. Results at or above 4.0 pCi/L are the expectation, not the exception, in many Nebraska communities.

Nebraska Radon in the Omaha and Lincoln Areas

Douglas County (Omaha) and Sarpy County (Bellevue, Papillion) are Zone 1 counties with among the highest average radon levels in the Omaha metropolitan area. Lancaster County (Lincoln) is also Zone 1. The eastern Nebraska glaciated region, where Omaha and Lincoln are located, consistently shows elevated radon readings across residential testing surveys. Both cities have substantial older housing stock with basements and concrete block foundations that can concentrate radon — making testing an urgent priority for homeowners who have not yet checked.

Nebraska Radon Testing Data

The Nebraska DHHS publishes county-level radon testing data derived from thousands of residential tests submitted through the state program. Nebraska’s testing data is among the most comprehensive in the Great Plains region, providing sub-county insights in larger metropolitan areas. The DHHS radon program can provide ZIP-code level guidance in some cases. For the most current data, contact the Nebraska DHHS Radon Program directly.

Nebraska New Construction and RRNC

Nebraska does not have a statewide RRNC mandate, but EPA and DHHS strongly recommend passive RRNC features in all new Nebraska residential construction. Given that 55% of Nebraska homes exceed the EPA action level — among the nation’s highest rates — every new home in Nebraska should have a passive radon vent pipe, sub-slab aggregate, vapor barrier, and attic electrical outlet installed during construction. The investment during the building phase is $350–$700; the same result after construction costs $800–$2,500.

Kansas has significant radon risk across much of the state. The Kansas Department of Health and Environment estimates that approximately 40% of Kansas homes have radon levels above 4.0 pCi/L. Kansas’s geology — including chalk and limestone formations in central Kansas, glacial till in the northeast, and uranium-bearing shale in the southeast — creates elevated radon potential across a broad swath of the state. Kansas has enacted radon contractor certification requirements.

EPA Radon Zone Designation

Most Kansas counties are Zone 1 or Zone 2. The highest-radon areas include northeastern Kansas counties with glacial geology (Leavenworth, Wyandotte, Johnson, Douglas, and Shawnee counties), the Flint Hills region of east-central Kansas where limestone formations are prevalent (Riley, Geary, Morris, Chase, and Marion counties), and north-central Kansas overlying chalk formations (Lincoln, Ellsworth, and McPherson counties).

Radon Contractor Licensing in Kansas

Kansas requires radon contractors to hold Kansas-approved certification for both radon measurement and mitigation. Kansas accepts NRPP or NRSB national certification as meeting state requirements. The Kansas Department of Health and Environment administers the state radon program and provides information on certified professionals. Verify contractor credentials at nrpp.info or nrsb.org, or through the KDHE radon program, before hiring.

Radon Disclosure Requirements in Kansas

Kansas’s real estate disclosure law requires sellers to disclose known material defects. Kansas does not have a radon-specific disclosure statute, but the general material defect disclosure obligation covers known elevated radon conditions. Kansas real estate transactions routinely include radon contingencies. Buyers in high-radon areas of Kansas should conduct independent testing during the inspection period.

Frequently Asked Questions

Does Kansas have significant radon risk?

Yes. The KDHE estimates approximately 40% of Kansas homes exceed 4.0 pCi/L. Northeastern, north-central, and east-central Kansas counties have the highest radon potential.

Does Kansas require radon contractor certification?

Yes. Kansas accepts NRPP or NRSB national certification as the operative credential for radon professionals. Verify credentials at nrpp.info or nrsb.org before hiring.

What parts of Kansas have the highest radon?

Northeastern Kansas (glacial geology), the Flint Hills region of east-central Kansas (limestone formations), and north-central Kansas (chalk formations) have the state’s highest average radon levels.

Kansas Radon Testing Resources and Data

The Kansas Department of Health and Environment (KDHE) Radiation Control Program publishes county-level radon data and maintains a list of NRPP/NRSB-certified contractors operating in Kansas. Kansas residents can request free or low-cost radon test kits through KDHE when funding is available — check the KDHE radon program website for current availability. Kansas State University Extension also provides radon educational resources and guidance for Kansas homeowners.

Radon in New Construction in Kansas

Kansas does not have a statewide RRNC mandate for new residential construction. EPA strongly recommends Radon-Resistant New Construction features for all new Kansas homes — particularly in Zone 1 northeastern, north-central, and Flint Hills region counties. The cost of including RRNC during construction ($350–$700) is a fraction of post-construction mitigation ($800–$2,500). Buyers of new construction in Kansas should ask their builder directly whether a passive radon vent pipe and sub-slab aggregate layer are included in the plans.

Radon Risk in Kansas Cities

The Kansas City metropolitan area (Johnson, Wyandotte, Leavenworth, and Douglas counties on the Kansas side) sits in Zone 1 to Zone 2 territory with meaningful radon risk. Shawnee County (Topeka, the state capital) is Zone 1. Sedgwick County (Wichita) is Zone 2 with moderate radon potential. Riley County (Manhattan, home of Kansas State University) is in the elevated Flint Hills zone. Regardless of location, all Kansas homes should be tested — the state’s 40% elevated prevalence rate means elevated radon is not an exception but an expectation in many communities.

Maine has significant radon risk, particularly in its granite-rich geological regions. The Maine Center for Disease Control and Prevention estimates that approximately 45% of Maine homes have radon levels above 4.0 pCi/L — one of the highest percentages in the northeastern United States. Maine’s geology includes extensive granitic formations, uranium-bearing schist, and glacially-deposited soils that create high radon potential across much of the state. Maine has enacted both contractor licensing and real estate disclosure requirements.

EPA Radon Zone Designation

Most Maine counties are Zone 1 or Zone 2. The highest-radon areas are concentrated in central and western Maine overlying granitic and metamorphic rock formations: Kennebec, Somerset, Oxford, Franklin, Androscoggin, Sagadahoc, and Cumberland counties show the state’s highest average readings. Coastal Washington and Hancock counties also have elevated radon potential due to granitic geology.

Radon Contractor Licensing in Maine

Maine requires radon contractors to hold a Maine state radon contractor license. Maine’s licensing program is administered by the Maine CDC Radiation Control Program. Licensure requires passing state examinations or demonstrating national NRPP/NRSB certification, carrying liability insurance, and meeting continuing education requirements. Maine maintains a list of licensed radon contractors. Performing radon measurement or mitigation in Maine without a state license is a violation of Maine law.

Radon Disclosure Requirements in Maine

Maine has radon-specific disclosure requirements for residential real estate transactions. Maine law requires sellers to disclose whether the home has been tested for radon and to provide any test results. The Maine Residential Property Disclosure Form includes specific radon questions. Maine is among the states with clear statutory radon disclosure obligations in real estate transactions — sellers who fail to disclose known elevated radon results may face post-closing liability.

Radon in Maine’s Older Housing Stock

Maine has a significant stock of older homes — many built before radon was a recognized issue in the 1980s and 1990s. Older homes, particularly those with block wall or stone foundations common in rural Maine, may have multiple radon entry pathways beyond the typical concrete slab scenario. Maine CDC recommends testing all homes regardless of age, and notes that older homes in granite-rich areas are among those most likely to benefit from mitigation.

Frequently Asked Questions

Is Maine a high-radon state?

Yes. The Maine CDC estimates approximately 45% of Maine homes have radon levels above 4.0 pCi/L — one of the highest rates in the Northeast. Maine’s granitic geology creates high radon potential across much of the state.

Does Maine require radon contractor licensing?

Yes. Maine requires a state radon contractor license administered by the Maine CDC Radiation Control Program. Verify license status before hiring any radon contractor.

Does Maine require radon disclosure when selling a home?

Yes. Maine law requires sellers to disclose whether the home has been tested for radon and to provide any known test results. The Maine Residential Property Disclosure Form includes specific radon questions.

Maine Radon in Older Housing Stock

Maine has a particularly high proportion of pre-1940 housing — farmhouses, cottages, and older residential stock built with stone, brick, or block foundations that predate any awareness of radon. These older foundations have significant cracks, mortar gaps, and structural openings that create multiple radon entry pathways. The combination of Maine’s high-uranium granite geology and its aging housing stock creates the conditions for some of the Northeast’s highest residential radon concentrations. The Maine CDC Radon Program specifically highlights older housing as a priority for testing.

Maine Radon in the Portland Metro

Cumberland County (Portland, South Portland, Falmouth, Westbrook, Windham) is Zone 1 with elevated radon risk throughout the greater Portland metropolitan area. Portland’s active real estate market — driven by remote work migration and strong demand for Maine coastal living — means radon should be a standard contingency in all Cumberland County transactions. York County (Southern Maine/Kittery, Sanford, Biddeford, Kennebunk) is Zone 1 to Zone 2 with meaningful radon risk. Androscoggin County (Lewiston-Auburn area) shows Zone 1 conditions with elevated average concentrations driven by the Norumbega Fault Zone geology.

Florida may seem an unlikely high-radon state given its tropical climate and reputation for flat, sandy soil. But parts of Florida — particularly the phosphate-rich central ridge region — have significant radon potential. Florida has enacted one of the more active southern state radon programs, with contractor licensing requirements and specific disclosure obligations. The Florida Department of Health administers the Florida Radon Program and the Building Radon Resistance Program (BRRP) for new construction.

EPA Radon Zone Designation

Florida counties range from Zone 1 in the central phosphate ridge region to Zone 2 and Zone 3 in coastal and southern counties. The highest-radon areas are concentrated in the central Florida phosphate region: Alachua, Columbia, Gilchrist, Hamilton, Hernando, Levy, Madison, Marion, Pasco, Polk, Putnam, Suwannee, and Taylor counties. North-central Florida counties show the state’s highest radon concentrations.

Radon Contractor Licensing in Florida

Florida has a comprehensive radon contractor licensing program. Florida law requires radon contractors to hold a Florida state radon license — the Florida Radon License is issued by the Florida Department of Health and requires passing state examinations, carrying liability insurance, and completing continuing education. Florida additionally requires that radon measurement in real estate transactions be conducted by a Florida-licensed radon measurement business. The Florida DOH maintains a searchable database of licensed radon contractors. Performing radon work without a Florida license is a violation of state law.

Radon Disclosure Requirements in Florida

Florida statute requires that buyers of residential property be provided with the Florida Radon Hazard Notification. Specifically, Florida Statute 404.056(5) requires that all contracts for sale and purchase of buildings include a disclosure statement about radon. The statutory disclosure language must appear in residential real estate contracts. Additionally, sellers who know of elevated radon test results have a duty to disclose this under Florida’s general material defect disclosure requirements.

Radon-Resistant New Construction in Florida

Florida has enacted the Building Radon Resistance Program (BRRP), which encourages RRNC features in new residential construction. The Florida Building Code incorporates provisions for radon-resistant construction in high-radon areas. Given Florida’s unique construction type — many homes are concrete block construction on slab foundations — RRNC implementation requires adaptations from the standard gravel sub-slab approach used in northern climates. The Florida DOH radon program provides technical guidance specific to Florida construction types.

Frequently Asked Questions

Does Florida have high radon levels?

Parts of Florida — particularly the central phosphate ridge region — have significant radon potential. North-central Florida counties overlying phosphate geology can have elevated radon levels comparable to many Zone 1 northern states. Coastal and southern Florida counties generally have lower levels.

Does Florida require radon contractor licensing?

Yes. Florida has a comprehensive radon contractor licensing program. Both measurement and mitigation require Florida state radon licenses, issued by the Florida Department of Health. Verify license status through the Florida DOH radon program before hiring.

Does Florida law require radon disclosure in real estate?

Yes. Florida Statute 404.056(5) requires that all residential real estate contracts include a radon hazard notification. Sellers with known elevated radon results have an additional duty to disclose under Florida’s material defect disclosure requirements.

Florida Phosphate Geology and Radon

North-central Florida’s phosphate mining region is the geological foundation of Florida’s radon risk. Phosphate deposits are naturally high in uranium — when phosphate is present in soil and rock, radon follows. The Florida phosphate belt runs through Hillsborough, Polk, Manatee, Hardee, Desoto, and Sarasota counties in west-central Florida, and through Alachua, Marion, Levy, Gilchrist, and Columbia counties in north-central Florida. Homes built over disturbed phosphate lands — including many in Hillsborough County (Tampa area) and Polk County (Lakeland area) — can have elevated radon even in the absence of a basement, because the phosphate-rich fill material itself can emit radon through slab-on-grade foundations.

Florida RRNC and Slab Construction Specifics

Florida’s Building Radon Resistance Program (BRRP) addresses the unique challenge of Florida’s predominantly slab-on-grade construction. Unlike northern states where basements provide a clear sub-slab entry point, Florida slab homes require specific RRNC techniques including: sub-slab vapor barriers sealed around all penetrations, a passive vent pipe through the slab and interior to above the roofline, and sealing of all slab penetrations. Florida’s warm climate means no stack effect advantage in summer — passive systems in Florida are less effective than in cold climates, making active (fan-powered) mitigation more likely to be needed even with RRNC features installed.

New Jersey has one of the most comprehensive state radon programs in the United States. The New Jersey Department of Environmental Protection (NJDEP) has administered an active radon program since the 1980s — driven partly by New Jersey’s historic role in radon risk discovery (the Stanley Watras case that put radon on the national map occurred in Boyertown, Pennsylvania, but the Reading Prong geological formation extends into New Jersey, creating similarly high radon potential). New Jersey has enacted both contractor licensing and school radon testing requirements.

EPA Radon Zone Designation

New Jersey counties range from Zone 1 in the northern portion of the state to Zone 2 in central and southern New Jersey. The highest-radon area in New Jersey is the northern region overlying the Reading Prong geological formation — specifically Morris, Somerset, Hunterdon, Warren, and Sussex counties — where average indoor radon levels are among the highest in the northeastern U.S. Bergen, Passaic, and Essex counties also show significant radon levels.

Radon Contractor Licensing in New Jersey

New Jersey has a comprehensive radon contractor licensing program administered by the NJDEP. New Jersey law requires radon contractors to hold a New Jersey state radon license — separate from and in addition to NRPP or NRSB national certification. New Jersey licensing requires passing the state radon contractor examination, maintaining liability insurance, and completing continuing education requirements. The NJDEP maintains a searchable online database of licensed radon professionals. Performing radon measurement or mitigation without a New Jersey license is a violation of state law.

Radon Disclosure Requirements in New Jersey

New Jersey requires sellers of residential real property to complete a Seller’s Property Disclosure Statement that includes questions about radon — whether the property has been tested, what the results were, and whether a radon mitigation system is installed. New Jersey sellers must disclose known radon test results. Radon testing is standard practice in New Jersey real estate transactions, particularly in northern Zone 1 counties. The NJDEP also requires distribution of the EPA radon pamphlet in certain transaction contexts.

School and Public Building Radon Testing in New Jersey

New Jersey requires radon testing in public schools and has specific provisions for childcare facilities. The New Jersey Department of Education and NJDEP have coordinated school radon testing programs. Results are reported to parents. New Jersey is among the states with the most active school radon testing programs in the northeastern U.S.

Frequently Asked Questions

Does New Jersey require radon contractor licensing?

Yes. New Jersey has a comprehensive state licensing program requiring contractors to hold a New Jersey radon license in addition to NRPP or NRSB certification. Verify license status through the NJDEP radon program before hiring.

What parts of New Jersey have the highest radon?

Northern New Jersey counties overlying the Reading Prong geological formation — Morris, Somerset, Hunterdon, Warren, and Sussex counties — have the highest radon potential in the state. Bergen, Passaic, and Essex counties also show elevated levels.

Does New Jersey require radon disclosure when selling a home?

Yes. The New Jersey Seller’s Property Disclosure Statement requires disclosure of known radon test results and the presence of any mitigation system.

New Jersey Radon Data and County Survey

The New Jersey Department of Environmental Protection has conducted comprehensive county-level radon surveys. Morris County consistently shows some of the state’s highest average indoor radon concentrations, reflecting the Reading Prong granite beneath the county. Somerset, Hunterdon, and Warren counties in the northwestern corner of the state also show very high averages. Sussex County in the northernmost corner of NJ has the state’s highest elevation and most concentrated granitic geology. The NJDEP’s online county radon data is one of the most complete state-level radon databases in the Northeast.

New Jersey Radon in Real Estate: Practical Context

New Jersey’s real estate market moves fast — inspection periods are often compressed to 7–10 days. This means radon testing must be ordered immediately when the inspection contingency period begins. Professional continuous radon monitors are commonly used in NJ real estate transactions because they produce results within 48–96 hours without the 3–7 day mail-to-lab turnaround of charcoal canisters. Many NJ home inspectors offer radon testing add-ons precisely because of the timing pressure. Buyers should confirm the testing timeline and device type before signing a contract.

Illinois has significant radon risk, with an estimated 35–40% of Illinois homes testing above the EPA action level of 4.0 pCi/L. The Illinois Emergency Management Agency (IEMA) Radon Section estimates that radon may be responsible for approximately 1,000 lung cancer deaths in Illinois annually — more deaths than are caused by drunk driving. Illinois has enacted some of the more comprehensive radon legislation in the Midwest, including contractor licensing requirements and school radon testing mandates.

EPA Radon Zone Designation

Illinois is predominantly EPA Radon Zone 1. Illinois counties range from Zone 1 in northern and central Illinois to Zone 2 in the southern portion of the state. The highest-radon areas are concentrated in the glaciated portions of northern and central Illinois where glacial till deposits overlie uranium-bearing geology. Northern Illinois counties in the Chicago metropolitan area and central Illinois agricultural counties show the highest average readings.

Radon Contractor Licensing in Illinois

Illinois has a comprehensive radon contractor licensing program. Illinois law requires radon contractors — both for measurement and for mitigation — to hold an Illinois state radon contractor license issued by the Illinois Emergency Management Agency. Illinois licensing requires passing state-approved training, holding NRPP or NRSB certification, carrying liability insurance, and paying licensing fees. Illinois maintains a searchable database of licensed radon contractors at iema.illinois.gov/radon. Performing radon measurement or mitigation without an Illinois radon license is a violation of Illinois law.

Radon Disclosure Requirements in Illinois

Illinois has enacted specific radon disclosure requirements for real estate transactions. Illinois law requires sellers of residential property to disclose known radon test results to buyers. Illinois uses a Residential Real Property Disclosure Act that includes radon — sellers must indicate whether they have received a radon test report and provide the report to buyers if one exists. Illinois also requires IEMA-approved radon pamphlets to be provided in certain transactions. Additionally, Illinois law requires radon testing in all public schools and mandates school radon disclosure to parents.

Radon-Resistant New Construction (RRNC) in Illinois

Illinois does not have a statewide RRNC mandate for new residential construction. However, the IEMA Radon Section strongly recommends RRNC for new construction in Illinois, particularly in Zone 1 northern and central counties. Some Illinois municipalities — particularly in the Chicago metropolitan area — have incorporated RRNC requirements locally. Buyers of new construction should ask about RRNC inclusion, especially in northern Illinois.

Highest-Radon Counties and Areas in Illinois

Illinois’s highest-radon areas are in the glaciated northern and central counties. The Chicago metropolitan area counties — Cook, DuPage, Kane, Lake, McHenry, Will, and Kendall — have elevated average radon levels. Central Illinois agricultural counties — including McLean, Tazewell, Peoria, Sangamon, and Champaign — also show significant radon levels. Southern Illinois counties generally have lower but still meaningful radon levels. IEMA publishes county-level radon data from the Illinois Radon Monitoring Program.

Testing Resources for Illinois Residents

The Illinois Emergency Management Agency (IEMA) Radon Section administers the state radon program and provides resources for homeowners including lists of certified contractors, low-cost or free test kit programs (availability varies by year and funding), and technical guidance on radon mitigation. Contact the state radon program directly for the most current contractor list, any available test kit distribution programs, and jurisdiction-specific requirements that may have changed since this page was last updated.

Frequently Asked Questions

Does Illinois require radon contractor licensing?

Yes. Illinois has one of the more comprehensive radon contractor licensing programs in the nation. Both measurement and mitigation contractors must hold an Illinois state radon license issued by IEMA, in addition to NRPP or NRSB national certification. Verify license status at iema.illinois.gov/radon.

Does Illinois require radon disclosure when selling a home?

Yes. Illinois law requires sellers to disclose known radon test results to buyers under the Residential Real Property Disclosure Act. If a radon test report exists, it must be provided to buyers.

Does Illinois require radon testing in schools?

Yes. Illinois law requires radon testing in all Illinois public schools. Results must be disclosed to parents. Illinois is among the states with the most comprehensive school radon testing mandates in the U.S.

Michigan has significant radon risk across much of the state, with an estimated 30–35% of Michigan homes testing above the EPA action level of 4.0 pCi/L. The Michigan Department of Environment, Great Lakes, and Energy (EGLE) estimates that radon may contribute to hundreds of lung cancer deaths in Michigan annually. Michigan’s geology — including granitic basement rock in the Upper Peninsula, glacial till and outwash across both peninsulas, and limestone formations in the Lower Peninsula — creates varied but often significant radon potential.

EPA Radon Zone Designation

Michigan is predominantly EPA Radon Zone 1. Michigan counties range from Zone 1 in parts of the Upper Peninsula and northern Lower Peninsula to Zone 2 in much of the southern Lower Peninsula. The Upper Peninsula counties overlying granitic basement rock tend to have higher radon potential. Northern Lower Peninsula counties in the glaciated sand and gravel deposits also show elevated levels.

Radon Contractor Licensing in Michigan

Michigan requires radon contractors to hold current NRPP or NRSB national certification. Michigan’s radon program is administered through the Michigan Department of Environment, Great Lakes, and Energy (EGLE). Michigan does not have a separate state radon contractor licensing statute — national certification through NRPP or NRSB is the operative requirement. EGLE maintains resources on radon and certified professionals. Verify contractor credentials at nrpp.info or nrsb.org before hiring.

Radon Disclosure Requirements in Michigan

Michigan’s real estate disclosure law requires sellers to complete a Seller’s Disclosure Statement disclosing known defects and conditions. The Michigan disclosure form includes questions about radon — specifically whether the property has been tested and what the results were, and whether a radon mitigation system is installed. Sellers must disclose known radon test results. Radon testing is standard practice in Michigan real estate transactions, particularly in northern Michigan and Upper Peninsula properties.

Radon-Resistant New Construction (RRNC) in Michigan

Michigan does not have a statewide RRNC mandate for new residential construction. The Michigan Building Code does not require RRNC features statewide. EGLE recommends RRNC for new construction in Zone 1 areas. The IRC Appendix F provisions are available for local adoption. Some Michigan municipalities have incorporated RRNC requirements locally. Buyers of new construction should ask builders about RRNC, particularly in northern Michigan and Upper Peninsula locations.

Highest-Radon Counties and Areas in Michigan

Michigan’s highest-radon areas include Upper Peninsula counties overlying granitic and iron-bearing bedrock: Marquette, Iron, Baraga, Houghton, Keweenaw, and Ontonagon counties. Northern Lower Peninsula counties with glacial sand and gravel deposits — including Kalkaska, Crawford, Roscommon, and Ogemaw counties — also show elevated levels. The EGLE publishes county-level radon data from testing surveys conducted across the state.

Testing Resources for Michigan Residents

The Michigan Department of Environment, Great Lakes, and Energy (EGLE) administers the state radon program and provides resources for homeowners including lists of certified contractors, low-cost or free test kit programs (availability varies by year and funding), and technical guidance on radon mitigation. Contact the state radon program directly for the most current contractor list, any available test kit distribution programs, and jurisdiction-specific requirements that may have changed since this page was last updated.

Frequently Asked Questions

Does Michigan require radon disclosure in real estate?

Yes. The Michigan Seller’s Disclosure Statement requires sellers to disclose known radon test results and the presence of any mitigation system. Sellers with knowledge of elevated radon levels must include this in their disclosure.

What parts of Michigan have the highest radon?

Upper Peninsula counties overlying granitic bedrock — particularly Marquette, Iron, Baraga, Houghton, and Keweenaw counties — have the highest radon potential. Northern Lower Peninsula counties with glacial sand and gravel also show elevated levels.

Does Michigan require radon contractor certification?

NRPP or NRSB national certification is required. No separate Michigan-specific licensing statute exists. Verify credentials at nrpp.info or nrsb.org before hiring any radon contractor.

Wisconsin has significant radon risk across much of the state, with an estimated 30–40% of Wisconsin homes testing above the EPA action level of 4.0 pCi/L. The Wisconsin Department of Health Services estimates that radon may be responsible for over 600 lung cancer deaths in Wisconsin annually. Wisconsin’s geology — including granitic bedrock in the northern shield area, glacial till across the state, and limestone formations in the southwestern driftless area — creates varied but often significant radon potential.

EPA Radon Zone Designation

Wisconsin is predominantly EPA Radon Zone 1. Most Wisconsin counties are Zone 1 or Zone 2. The highest-radon areas tend to be in the northern Wisconsin shield counties where granitic bedrock is close to the surface, and in the central sand plain counties where glacial outwash creates radon transport pathways. Southern Wisconsin counties overlying carbonate rock also show elevated levels.

Radon Contractor Licensing in Wisconsin

Wisconsin requires radon contractors to hold current NRPP or NRSB national certification to perform radon measurement and mitigation services. Wisconsin’s radon program is administered through the Wisconsin Department of Health Services. Wisconsin does not have a separate state-specific radon contractor licensing statute — national certification is the operative requirement. The WDHS maintains resources and information on certified professionals. Verify contractor credentials at nrpp.info or nrsb.org before hiring.

Radon Disclosure Requirements in Wisconsin

Wisconsin’s real estate disclosure law requires sellers to complete a Real Estate Condition Report disclosing known defects and conditions. The Wisconsin Real Estate Condition Report includes questions about environmental conditions including whether the property has been tested for radon and the results of any such tests, and whether a radon mitigation system is present. Sellers with knowledge of radon test results must disclose them. Radon testing is common in Wisconsin real estate transactions, particularly in high-radon areas.

Radon-Resistant New Construction (RRNC) in Wisconsin

Wisconsin does not have a statewide RRNC mandate for new residential construction. The Wisconsin Uniform Dwelling Code does not require RRNC features statewide. However, Wisconsin DHS recommends RRNC for new construction in Zone 1 areas. The IRC Appendix F provisions are available for local adoption. Some Wisconsin municipalities have incorporated RRNC requirements. Buyers of new Wisconsin construction should ask builders about RRNC inclusion.

Highest-Radon Counties and Areas in Wisconsin

Wisconsin’s highest-radon areas include the northern shield counties where granitic bedrock is prevalent: Iron, Ashland, Bayfield, Douglas, and Vilas counties. The glaciated central Wisconsin sand plain counties (Adams, Portage, Waushara, Waupaca, Marathon) also show elevated levels. The Milwaukee metropolitan area (Milwaukee, Waukesha, Ozaukee, Washington counties) spans the transition between Zone 1 and Zone 2 areas. The Wisconsin DHS publishes county-level radon data from testing surveys.

Testing Resources for Wisconsin Residents

The Wisconsin Department of Health Services administers the state radon program and provides resources for homeowners including lists of certified contractors, low-cost or free test kit programs (availability varies by year and funding), and technical guidance on radon mitigation. Contact the state radon program directly for the most current contractor list, any available test kit distribution programs, and jurisdiction-specific requirements that may have changed since this page was last updated.

Frequently Asked Questions

Does Wisconsin require radon disclosure when selling a home?

Yes. The Wisconsin Real Estate Condition Report requires sellers to disclose known radon test results and the presence of any radon mitigation system. Sellers with knowledge of elevated radon must disclose it.

What parts of Wisconsin have the highest radon?

Northern Wisconsin shield counties — Iron, Ashland, Bayfield, Douglas, Vilas — have the highest radon potential due to granitic bedrock. Central Wisconsin sand plain counties and parts of southern Wisconsin with carbonate geology also show elevated levels.

Does Wisconsin require radon contractor certification?

NRPP or NRSB national certification is required for radon professionals in Wisconsin. No separate state licensing statute exists. Verify credentials at nrpp.info or nrsb.org before hiring.

South Dakota has the third-highest average indoor radon level of any U.S. state, estimated at approximately 7.3 pCi/L statewide. The South Dakota Department of Agriculture and Natural Resources estimates that approximately 60% of South Dakota homes have radon levels above 4.0 pCi/L. South Dakota’s geology — including granitic rock in the Black Hills, glacial till across the east, and uranium-bearing formations — creates some of the highest radon potential in the nation.

EPA Radon Zone Designation

South Dakota is predominantly EPA Radon Zone 1. All South Dakota counties are Zone 1. The Black Hills region in western South Dakota overlies some of the most uranium-rich geology in the U.S., including formations associated with historic uranium mining. Eastern South Dakota counties in the glaciated plains also show consistently high radon levels.

Radon Contractor Licensing in South Dakota

South Dakota requires radon contractors to hold current NRPP or NRSB national certification. The South Dakota Department of Agriculture and Natural Resources administers the state radon program. South Dakota does not have a separate state radon contractor licensing law — national certification is the operative requirement. Verify contractor credentials at nrpp.info or nrsb.org before engaging any radon professional.

Radon Disclosure Requirements in South Dakota

South Dakota’s real estate disclosure requirements under general property disclosure law require sellers to disclose known material defects. South Dakota does not have a radon-specific disclosure statute. However, given that 60% of South Dakota homes exceed the EPA action level, radon is a significant known risk that sellers should address in disclosures when they have knowledge of test results. Real estate agents in South Dakota routinely recommend radon testing during the inspection period.

Radon-Resistant New Construction (RRNC) in South Dakota

South Dakota does not have a statewide RRNC mandate. Given the state’s Zone 1 designation across all counties and one of the nation’s highest average radon levels, EPA and SDANR strongly recommend RRNC for all new South Dakota residential construction. Buyers of new construction — particularly in the Black Hills region and eastern glaciated counties — should request RRNC inclusion in construction contracts.

Highest-Radon Counties and Areas in South Dakota

The Black Hills counties of western South Dakota (Lawrence, Pennington, Custer, Fall River, Meade, Butte) have some of the highest radon potential in the state due to uranium-bearing granitic geology. Eastern South Dakota counties in the glaciated plains — including Minnehaha (Sioux Falls area), Lincoln, Turner, and Lake counties — also show consistently high average readings. The SDANR publishes county-level radon survey data.

Testing Resources for South Dakota Residents

The South Dakota Department of Agriculture and Natural Resources administers the state radon program and provides resources for homeowners including lists of certified contractors, low-cost or free test kit programs (availability varies by year and funding), and technical guidance on radon mitigation. Contact the state radon program directly for the most current contractor list, any available test kit distribution programs, and jurisdiction-specific requirements that may have changed since this page was last updated.

Frequently Asked Questions

How high is radon in South Dakota?

South Dakota has the third-highest average indoor radon level in the U.S. — approximately 7.3 pCi/L. About 60% of South Dakota homes exceed the EPA action level. All 66 counties are Zone 1.

Does South Dakota require radon contractor certification?

NRPP or NRSB national certification is required. No separate state licensing law exists. Verify credentials at nrpp.info or nrsb.org before hiring.

Is the Black Hills area particularly high in radon?

Yes. The Black Hills counties have some of the highest radon potential in South Dakota due to uranium-bearing granitic formations. Lawrence, Pennington, Custer, and Fall River counties are among the highest-radon areas in the state.