Category: Regulations & Certification

West Virginia has significant radon risk statewide due to its Appalachian geology. The West Virginia Department of Health and Human Resources estimates that approximately 40% of West Virginia homes have radon levels above 4.0 pCi/L. West Virginia’s coal-bearing Appalachian formations, black shale, and sedimentary geology create elevated radon potential across much of the state. Virtually all of West Virginia’s counties have meaningful radon risk.

EPA Radon Zone Designation

Most West Virginia counties are Zone 1 or Zone 2. The northern and eastern counties overlying black shale and coal formations — including Monongalia, Marion, Harrison, Lewis, Upshur, Barbour, Tucker, Randolph, Pendleton, Hardy, Hampshire, Morgan, and Berkeley counties — show the highest average readings. The Eastern Panhandle counties (Berkeley, Jefferson, Morgan) are in the high-radon corridor extending from the Reading Prong formation in Pennsylvania and Maryland.

Radon Contractor Requirements in West Virginia

West Virginia requires radon contractors to hold NRPP or NRSB national certification. The West Virginia Department of Health and Human Resources administers radon program resources. West Virginia does not have a separate state radon licensing statute beyond national certification. Verify contractor credentials at nrpp.info or nrsb.org before hiring any radon professional.

Radon Disclosure in West Virginia

West Virginia’s Residential Property Disclosure Act requires sellers to disclose known material defects. West Virginia does not have a radon-specific disclosure statute, but known elevated radon conditions are material information that sellers should disclose under the general duty. The West Virginia Real Estate Commission provides guidance on radon disclosure.

Frequently Asked Questions

Is West Virginia a high-radon state?

Yes. Approximately 40% of West Virginia homes exceed 4.0 pCi/L. West Virginia’s Appalachian geology creates significant radon risk statewide, with the northern and eastern counties showing the highest average levels.

Is the Charleston or Morgantown area high in radon?

Monongalia County (Morgantown) is a Zone 1 county with elevated radon risk. Kanawha County (Charleston) is Zone 2. Both areas warrant radon testing, and testing is particularly important in Morgantown and northern West Virginia.

Does West Virginia require radon contractor certification?

NRPP or NRSB national certification is required. No separate West Virginia licensing statute. Verify credentials at nrpp.info or nrsb.org before hiring.

Eastern Panhandle High-Radon Corridor

West Virginia’s Eastern Panhandle counties — Berkeley, Jefferson, and Morgan — sit in the extension of the high-radon corridor that runs from Reading Prong Pennsylvania through Maryland into northern West Virginia. Berkeley County (Martinsburg area) and Jefferson County (Charles Town, Harpers Ferry) show elevated radon consistent with the Shenandoah Valley and Blue Ridge geology of this corridor. The rapid residential growth in the Eastern Panhandle — which serves as a bedroom community for the Washington D.C. metropolitan area — means many newer homes in this Zone 1 area should have been built with RRNC features, though this is not mandated statewide.

Morgantown and University Town Radon

Monongalia County (Morgantown, home of West Virginia University) is Zone 1 with elevated radon potential. The county’s Devonian and Mississippian shale formations underlie the mountainous terrain around Morgantown. Student rental housing, which often occupies older basement-heavy structures, can have radon levels that create significant cumulative exposure for student residents who spend multiple years in the area. WVU’s environmental health programs have been involved in radon awareness efforts for the Morgantown community.

West Virginia Testing Resources

The West Virginia Department of Health and Human Resources (WVDHHR) Radon Program provides testing resources, certified contractor information, and educational materials. WV participates in EPA’s SIRG program. Contact WVDHHR for the current certified contractor list and information on any available test kit assistance programs. The NRPP directory (nrpp.info) searchable by zip code provides real-time certification verification for all WV counties.

Kentucky has significant radon risk, particularly in its eastern Appalachian counties. The Kentucky Radon Program estimates that approximately 30% of Kentucky homes have radon levels above 4.0 pCi/L, with considerably higher percentages in Eastern Kentucky where Appalachian geology creates elevated radon potential. Kentucky’s limestone karst geology in the central Bluegrass region also creates radon pathways in some areas.

EPA Radon Zone Designation

Eastern Kentucky Appalachian counties are Zone 1 or Zone 2: Bell, Boyd, Breathitt, Carter, Clay, Elliott, Floyd, Greenup, Harlan, Jackson, Johnson, Knott, Knox, Lawrence, Lee, Leslie, Letcher, Lewis, Magoffin, Martin, McCreary, Menifee, Morgan, Owsley, Perry, Pike, Powell, Rowan, Wayne, and Whitley counties. The Bluegrass region and western Kentucky counties are generally Zone 2 to Zone 3.

Radon Contractor Requirements in Kentucky

Kentucky requires radon contractors to hold NRPP or NRSB national certification. Kentucky’s radon program is administered through the Kentucky Cabinet for Health and Family Services. Kentucky does not have a separate state radon licensing statute beyond national certification requirements. Verify contractor credentials at nrpp.info or nrsb.org before hiring.

Radon Disclosure in Kentucky

Kentucky’s real estate disclosure law requires sellers to disclose known material defects through the Kentucky Seller’s Disclosure of Property Condition. Known elevated radon results should be disclosed. Radon testing is particularly important in Eastern Kentucky transactions where the Appalachian geology creates high radon potential.

Frequently Asked Questions

What parts of Kentucky have the highest radon?

Eastern Kentucky’s Appalachian counties have the highest radon potential — particularly the coal-bearing counties of Pike, Floyd, Harlan, Letcher, Bell, and surrounding areas. The Lexington Bluegrass region shows moderate levels; Western Kentucky generally has lower but still meaningful radon risk.

Does Kentucky require radon contractor certification?

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

Should I test for radon in Louisville or Lexington?

Yes. Jefferson County (Louisville) is Zone 2 with meaningful radon risk. Fayette County (Lexington) is in the Bluegrass Zone 2 area. Testing is recommended for all Kentucky homes, and should be standard in real estate transactions statewide.

Eastern Kentucky Coal Country Radon

Eastern Kentucky’s coal-bearing counties — Pike, Floyd, Harlan, Letcher, Perry, Knott, Leslie, and surrounding Appalachian counties — show some of the state’s highest average radon concentrations. The Pennsylvanian-age coal measures of the Cumberland Plateau and Pine Mountain region contain organic shale formations associated with elevated uranium concentrations. Homes in the mountain hollows of Eastern Kentucky, many with block or stone foundations built into hillsides, can have significant radon entry pathways from multiple directions.

Central Kentucky Bluegrass Radon

The Lexington Bluegrass region — Fayette County and surrounding counties including Madison, Clark, Bourbon, Scott, Woodford, and Jessamine — overlies Ordovician limestone and carbonate formations. These formations create karst topography (caves, sinkholes, and solution channels) that can serve as radon migration pathways. Fayette County shows Zone 2 radon levels with meaningful risk for Lexington homeowners. The Lexington area’s horse farm country, with older stone and block construction on larger rural properties, can have elevated radon particularly in older structures.

Kentucky Testing Resources

The Kentucky Cabinet for Health and Family Services (CHFS) Radon Program provides testing resources, certified contractor information, and county-level radon data. Kentucky participates in EPA’s SIRG program. The Kentucky Radon Program can provide guidance on test kit sources, certified contractor lists, and post-mitigation verification protocol. Contact CHFS directly or search nrpp.info for certified Kentucky radon contractors.

Utah has significant radon risk, with an estimated 40–45% of Utah homes testing above the EPA action level of 4.0 pCi/L. Utah’s geology — including uranium-bearing sandstone formations (Colorado Plateau), volcanic rock, granitic mountain ranges, and the Wasatch Front urban corridor geology — creates high radon potential across much of the state. Utah’s history as a major uranium mining state contributes to widespread radon-productive geological formations.

EPA Radon Zone Designation

Most Utah counties are Zone 1 or Zone 2. The Wasatch Front counties — Salt Lake, Utah, Davis, and Weber counties — show elevated radon levels and contain the vast majority of Utah’s population. Cache County (Logan area) and Summit County are also Zone 1. The Colorado Plateau counties of southeastern Utah — San Juan, Carbon, Emery, and Grand counties — overlie uranium-bearing sandstone and show high radon potential.

Radon Contractor Requirements in Utah

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

Radon in Utah’s Wasatch Front

The Wasatch Front urban corridor — where approximately 80% of Utah’s population lives — has significant radon risk. Salt Lake County homes, particularly older homes on the east bench with proximity to the Wasatch Range granitic geology, show elevated radon levels. The rapid pace of new residential construction along the Wasatch Front makes RRNC inclusion a significant public health opportunity. Utah DEQ strongly recommends testing for all Wasatch Front homes.

Frequently Asked Questions

Is the Salt Lake City area high in radon?

Yes. Salt Lake County and surrounding Wasatch Front counties — Utah, Davis, Weber — are Zone 1 or Zone 2 with elevated radon potential. Radon testing is recommended for all Wasatch Front homes, particularly those on the east bench near the mountain geology.

Does Utah require radon contractor licensing?

No. Utah has no state licensing statute. NRPP or NRSB national certification is the operative credential. Search nrpp.info for certified Utah contractors.

Why does Utah have high radon levels?

Utah sits on extensive uranium-bearing geological formations — the same Colorado Plateau sandstones that made Utah a major uranium mining state. Granitic mountain geology along the Wasatch Front also contributes. Combined with common slab-on-grade and basement construction in the Wasatch Front corridor, these create significant radon entry pathways.

Salt Lake and Utah County Radon Data

Salt Lake County and Utah County (Provo/Orem area) are the two most populous counties in Utah and show Zone 1 to Zone 2 radon levels. The east bench communities of Salt Lake City — Holladay, Millcreek, Cottonwood Heights — that sit closer to the Wasatch Range granite geology tend to show higher radon than lower valley communities. Utah County’s Provo-Orem corridor has similar patterns. Summit County (Park City) is Zone 1 with elevated radon from mountain granitic geology — a significant consideration given the area’s active real estate market and high-value homes.

Colorado Plateau Radon in Southeastern Utah

Southeastern Utah counties — San Juan, Carbon, Emery, Grand, and Garfield — sit on the Colorado Plateau’s uranium-bearing Chinle and Morrison Formation sandstones. The same geological formations that once supported extensive uranium mining in the Moab area (Grand County) produce ongoing radon in residential buildings. Carbon County (Price) and Emery County have historically elevated radon readings. Even in smaller southeastern Utah communities, radon testing is warranted.

Utah Testing Resources

The Utah Department of Environmental Quality (UDEQ) Division of Radiation Control administers the state radon program. UDEQ provides county-level radon data, certified contractor information, and educational materials. Utah participates in EPA’s SIRG program. The UDEQ radon program can provide specific guidance on testing methodology and interpretation for Utah’s unique geological context. Contact UDEQ or search nrpp.info by zip code for certified Utah radon professionals.

Idaho has significant radon risk, with an estimated 45% of Idaho homes testing above the EPA action level of 4.0 pCi/L. Idaho’s geology — including the Idaho Batholith (one of the largest granite formations in the U.S.), uranium-bearing rock in central and southern Idaho, and volcanic basalt on the Snake River Plain — creates varied but often high radon potential. The Idaho Department of Health and Welfare administers the state radon program.

EPA Radon Zone Designation

Most Idaho counties are Zone 1 or Zone 2. The highest-radon areas include northern Idaho counties overlying the Idaho Batholith granitic formations (Clearwater, Idaho, Latah, Lewis, and Nez Perce counties), central Idaho mining district counties (Custer, Lemhi, Blaine, and Camas counties), and southwestern Idaho counties including Ada (Boise metro) and Canyon counties. The Snake River Plain counties (Jefferson, Bingham, Bonneville) are generally Zone 2.

Radon Contractor Requirements in Idaho

Idaho does not have a state radon contractor licensing statute. Idaho relies on NRPP and NRSB national certification as the operative credentials for radon professionals. The Idaho Department of Health and Welfare maintains radon program resources but does not operate a separate state licensing program. Search the NRPP directory at nrpp.info or nrsb.org for certified Idaho radon professionals.

Radon Disclosure Requirements in Idaho

Idaho’s Seller Property Disclosure Act requires sellers to disclose known material defects. Idaho does not have a radon-specific disclosure statute, but known elevated radon conditions are material information that sellers should disclose under the general duty. The Idaho Real Estate Commission provides guidance on radon as a potential disclosure item.

Frequently Asked Questions

Why is Idaho a high-radon state?

Idaho sits on the Idaho Batholith — one of the nation’s largest granite formations — along with uranium-bearing rock in the central mining districts. These uranium-rich geological formations produce significant radon, particularly in northern and central Idaho.

Does Idaho require radon contractor licensing?

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

Is the Boise area high in radon?

Ada County (Boise) and Canyon County are designated Zone 1 or Zone 2. Radon testing is recommended for all Treasure Valley homes. Northern Idaho counties overlying the Idaho Batholith generally have higher average levels than the Boise area.

Northern Idaho Mining Districts and Radon

Northern Idaho’s mining history — silver, lead, zinc, and gold mining in the Coeur d’Alene mining district — is associated with geology that also produces elevated radon. Shoshone County (the Silver Valley/Coeur d’Alene mining district) and Benewah, Kootenai, and Bonner counties in the Idaho Panhandle show significant radon potential. Clearwater County, Idaho County, and Lewis County in the north-central Idaho Clearwater region overlie the Idaho Batholith with high uranium content.

Boise Metro Radon Specifics

The Treasure Valley (Ada and Canyon counties) has Zone 1 to Zone 2 radon designation. The Boise Front — the foothills rising from the valley floor toward the Boise Mountains — shows higher average radon levels than the lower valley floor. Homes built on or near the foothills, or in older established Boise neighborhoods closer to the mountain geology, tend to test higher. Canyon County (Nampa, Caldwell) shows similar patterns to Ada County. Eagle, Meridian, and Star — rapidly growing Treasure Valley communities — warrant testing regardless of new construction date.

Idaho Testing Resources

The Idaho Department of Health and Welfare (IDHW) Bureau of Community and Environmental Health administers radon program resources. IDHW participates in EPA’s SIRG program. Idaho does not have a comprehensive state testing database as large as some states, but IDHW provides county-level risk information and certified contractor referrals. The NRPP directory (nrpp.info) searchable by zip code is the most reliable way to find certified Idaho radon professionals.

Tennessee has significant radon risk, particularly in its eastern Appalachian counties. The Tennessee Department of Environment and Conservation estimates that approximately 30% of Tennessee homes have radon levels above 4.0 pCi/L statewide, with considerably higher percentages in Eastern Tennessee where the Appalachian geology creates elevated radon potential. Tennessee has enacted radon contractor licensing requirements.

EPA Radon Zone Designation

Eastern Tennessee counties overlying the Appalachian ridge and valley geology are Zone 1: Anderson, Blount, Bradley, Campbell, Claiborne, Cumberland, Grainger, Greene, Hamilton, Hawkins, Jefferson, Knox, Loudon, McMinn, Meigs, Monroe, Morgan, Polk, Rhea, Roane, Scott, Sevier, Sullivan, Union, and Washington counties. Middle and West Tennessee counties are generally Zone 2 to Zone 3.

Radon Contractor Licensing in Tennessee

Tennessee requires radon contractors to hold current NRPP or NRSB national certification, and Tennessee has additional state registration requirements for radon professionals. The Tennessee Department of Environment and Conservation administers radon program resources. Tennessee maintains a registry of radon measurement and mitigation service providers. Verify contractor credentials through TDEC and through the national NRPP/NRSB directories before hiring.

Radon Disclosure Requirements in Tennessee

Tennessee’s Residential Property Condition Disclosure Act requires sellers to disclose known material defects. The Tennessee disclosure form includes environmental conditions — sellers with knowledge of elevated radon test results should disclose them. Tennessee does not have a radon-specific disclosure statute, but the general material defect obligation applies. Radon testing is particularly important in Eastern Tennessee transactions.

Frequently Asked Questions

What parts of Tennessee have the highest radon?

Eastern Tennessee’s Appalachian counties — including Knox (Knoxville), Hamilton (Chattanooga), Bradley, Anderson, and surrounding ridge-and-valley counties — have the state’s highest radon potential. Middle and West Tennessee counties generally have lower levels.

Does Tennessee require radon contractor certification?

Tennessee requires NRPP or NRSB national certification and has additional state registration requirements. Verify credentials through TDEC and nrpp.info before hiring.

Should I test for radon in Knoxville or Chattanooga?

Yes. Both Knoxville (Knox County) and Chattanooga (Hamilton County) are in Zone 1 Appalachian counties. Radon testing is strongly recommended for all homes in Eastern Tennessee, and should be standard in real estate transactions in these areas.

Knoxville and Chattanooga Area Radon

Knox County (Knoxville) and Hamilton County (Chattanooga) are Zone 1 Appalachian counties where radon is a significant public health concern. The Knoxville metropolitan area — which includes Knox, Anderson, Blount, Loudon, Sevier, Union, and Grainger counties — sits within the Appalachian Valley and Ridge province where limestone, dolostone, and shale formations create both radon-producing geology and preferential pathways for radon migration into homes. The Tennessee Department of Environment and Conservation (TDEC) has documented elevated radon testing results throughout the Knoxville metro.

Tennessee Testing Resources

The Tennessee Department of Environment and Conservation Radon Program provides resources including information on certified contractors, radon testing guidance, and educational materials for homeowners. TDEC participates in EPA’s SIRG program. Tennessee also participates in the Appalachian Regional Radon Outreach Initiative, which coordinates radon awareness across Appalachian states. Contact TDEC directly for the current certified contractor list and any test kit assistance programs.

Radon in Nashville and Memphis

Davidson County (Nashville) is Zone 2 with moderate radon potential. The Nashville Basin’s limestone geology creates some radon risk, though lower than the Appalachian counties to the east. Shelby County (Memphis) is Zone 2 to Zone 3. Middle and West Tennessee homeowners should still test — the 30% statewide prevalence rate means elevated radon is found throughout Tennessee, not just in the eastern Appalachian counties.

New York State has significant radon risk across much of its interior — away from the coastal metropolitan areas, New York’s geology of granite, gneiss, and shale creates elevated radon potential. The New York State Department of Health estimates that approximately 35% of New York homes outside New York City have radon levels above 4.0 pCi/L. New York has enacted radon contractor certification requirements and requires radon testing disclosure in real estate transactions.

EPA Radon Zone Designation

New York State counties range from Zone 1 in portions of the Hudson Valley, Capital Region, and Southern Tier to Zone 2 in Long Island and Zone 3 in parts of New York City. The highest-radon areas include: Clinton, Essex, Hamilton, Fulton, and Warren counties in the Adirondack region overlying granitic bedrock; Columbia, Greene, Ulster, and Sullivan counties in the Hudson Valley/Catskills region; and Tompkins, Chemung, Steuben, and Allegany counties in the Southern Tier.

Radon Contractor Licensing in New York

New York requires radon contractors to hold a New York State radon contractor certification issued by the New York State Department of Health. New York’s certification program requires demonstrating NRPP or NRSB certification and meeting state-specific requirements. The NYSDOH maintains a list of certified radon contractors. Performing radon measurement or mitigation in New York without state certification is a violation of New York Public Health Law.

Radon Disclosure Requirements in New York

New York’s Property Condition Disclosure Act requires sellers to complete a Property Condition Disclosure Statement. The New York PCDS includes questions about environmental conditions — sellers must disclose whether they have knowledge of elevated radon levels or whether a radon mitigation system is present. Sellers who have received elevated radon test results must disclose them. New York buyers should independently test during the inspection period regardless of seller disclosure status.

Frequently Asked Questions

Does New York require radon contractor certification?

Yes. New York requires state radon contractor certification from the NYSDOH. Verify certification status through the New York State Department of Health before hiring any radon professional.

What parts of New York State have the highest radon?

The Adirondack region (Clinton, Essex, Hamilton, Fulton, Warren counties), Hudson Valley and Catskills (Columbia, Greene, Ulster, Sullivan counties), and Southern Tier (Tompkins, Chemung, Steuben, Allegany counties) have the state’s highest radon potential. New York City and Long Island generally have lower levels.

Does New York require radon disclosure in real estate?

Yes. The New York Property Condition Disclosure Statement requires sellers to disclose known elevated radon conditions and the presence of any mitigation system.

New York City and Long Island Radon Context

New York City (all five boroughs) is predominantly Zone 3 with the lowest radon potential in the state — largely due to the dense urban construction, higher air exchange rates in multifamily buildings, and the specific geology beneath the city. Long Island (Nassau and Suffolk counties) is Zone 2. This does not mean radon is absent in NYC or Long Island, but average concentrations are substantially lower than upstate New York. Ground-floor and basement apartments in older building types throughout the metro area can still have elevated levels.

Capital Region and Hudson Valley Radon

The Albany-Schenectady-Troy metropolitan area (Albany, Schenectady, and Rensselaer counties) overlies a mix of shale, limestone, and glacial geology and shows Zone 1 to Zone 2 radon levels. Ulster County (Kingston area), Greene County (Catskill Mountains), and Columbia County in the Hudson Valley are Zone 1, with elevated radon driven by the region’s granitic and metamorphic geology. The Southern Tier cities — Binghamton (Broome County), Elmira (Chemung County), and Corning (Steuben County) — are in high-radon Zone 1 areas.

New York State Testing Resources

The New York State Department of Health (NYSDOH) Radiation Protection Bureau administers the state radon program. NYSDOH maintains a searchable database of certified radon service providers, county-level radon data from state testing surveys, and educational resources. New York State participates in EPA’s SIRG program, which funds testing assistance and contractor certification support. Contact NYSDOH directly for the current certified contractor list and any available test kit programs.

Virginia has significant radon risk in its northern and western regions, particularly the Northern Virginia suburbs of Washington D.C. and the Shenandoah Valley. The Virginia Department of Health estimates that approximately 30% of Virginia homes have radon levels above 4.0 pCi/L statewide, with considerably higher percentages in the northern and western areas. Virginia has enacted both radon contractor licensing and specific real estate disclosure requirements.

EPA Radon Zone Designation

Virginia counties range significantly by zone. Northern Virginia counties (Loudoun, Fauquier, Clarke, Warren, Shenandoah, Page, Rockingham, Augusta, Rockbridge, and Bath) overlying the Shenandoah Valley limestone and Blue Ridge geology are Zone 1. Northern Virginia suburban counties (Fairfax, Prince William, Stafford) show elevated levels. Central and southeastern Virginia counties are predominantly Zone 2 to Zone 3.

Radon Contractor Licensing in Virginia

Virginia requires radon contractors to hold a Virginia Department of Professional and Occupational Regulation (DPOR) radon license for both measurement and mitigation work. Virginia’s radon licensing program is administered by DPOR and requires passing the licensing examination, demonstrating NRPP or NRSB certification, carrying liability insurance, and completing continuing education. The DPOR maintains a searchable database of licensed radon professionals. Performing radon work without a Virginia radon license is a violation of the Virginia Radon Contractor Licensing Act.

Radon Disclosure Requirements in Virginia

Virginia enacted radon disclosure requirements as part of its residential real estate disclosure law. The Virginia Residential Property Disclosure Act requires sellers to provide buyers with a disclosure statement, and while Virginia uses a disclaimer system (sellers may disclaim rather than warrant certain conditions), known elevated radon levels are material conditions that sellers should disclose. Virginia also requires distribution of the EPA radon pamphlet in real estate transactions in certain circumstances.

Frequently Asked Questions

Does Virginia require radon contractor licensing?

Yes. Virginia requires radon contractors to hold a DPOR radon license for both measurement and mitigation. Verify license status through the Virginia DPOR before hiring any radon professional.

What parts of Virginia have the highest radon?

The Shenandoah Valley counties of western Virginia — Shenandoah, Page, Rockingham, Augusta, Rockbridge, and Bath counties — and northern Piedmont counties including Loudoun and Fauquier have the highest radon potential. Northern Virginia suburban counties also show elevated levels.

Is radon disclosure required in Virginia real estate?

Virginia uses a property disclosure/disclaimer system. Known material conditions including elevated radon should be disclosed. Radon testing is standard practice in Northern Virginia and Shenandoah Valley transactions.

Northern Virginia Radon Risk

The Northern Virginia suburban corridor — Fairfax, Loudoun, Prince William, Stafford, and Fauquier counties — has significant radon risk, with many areas in Zone 1 due to Piedmont crystalline geology beneath the suburban development. Loudoun County, which has experienced rapid residential growth, has a substantial share of homes with elevated radon levels. Fairfax County — the state’s most populous — shows Zone 1 to Zone 2 levels with meaningful risk throughout. Given the area’s dense housing market and active real estate transactions, radon testing is essentially standard practice in Northern Virginia buyer due diligence.

Shenandoah Valley Radon Specifics

The Shenandoah Valley’s limestone and carbonate geology creates elevated radon potential that extends from Pennsylvania’s south-central counties southward through western Virginia. Shenandoah, Page, Rockingham (Harrisonburg), Augusta (Staunton/Waynesboro), Rockbridge (Lexington), and Bath counties consistently show elevated average radon levels in Virginia Department of Health data. Homes in the Valley — particularly older farmhouses with stone foundations and block walls — can have very high radon concentrations.

Virginia Testing Resources

The Virginia Department of Health (VDH) Radon Program provides information on certified contractors and radon testing resources. The VDH participates in EPA’s SIRG program. The Virginia Department of Professional and Occupational Regulation (DPOR) maintains the official database of licensed Virginia radon contractors — verify any contractor’s DPOR license before hiring at dpor.virginia.gov. Licensed radon professionals are separately listed from general contractors; confirm the specific radon license is current.

Maryland has significant radon risk, particularly in its western and central counties overlying the Reading Prong and Piedmont geological formations. The Maryland Department of the Environment estimates that approximately 40% of Maryland homes have radon levels above the EPA action level of 4.0 pCi/L. Maryland has enacted contractor licensing requirements and, for certain counties, RRNC requirements for new construction.

EPA Radon Zone Designation

Maryland counties are Zone 1 in the western and central portions of the state — Montgomery, Frederick, Carroll, Baltimore, Harford, Cecil, Howard, and Washington counties show the state’s highest average radon levels. These counties overlie Piedmont crystalline rock and Reading Prong granite. Eastern Shore and southern Maryland counties are generally Zone 2 to Zone 3.

Radon Contractor Licensing in Maryland

Maryland requires radon contractors to hold a Maryland state radon license for both measurement and mitigation work. The Maryland Department of the Environment administers the state radon licensing program. Licensure requires passing state examinations or demonstrating NRPP/NRSB certification, carrying liability insurance, and completing continuing education. The MDE maintains a searchable database of licensed radon professionals. Performing radon work without a Maryland license is a violation of state law.

Radon Disclosure Requirements in Maryland

Maryland requires sellers to disclose known material defects under the Maryland Residential Property Disclosure and Disclaimer Statement. This form includes radon-related questions — specifically whether the property has been tested for radon and what the results were, and whether a mitigation system is installed. Maryland sellers with knowledge of elevated radon test results must disclose them. Radon testing is standard practice in western and central Maryland real estate transactions.

Radon-Resistant New Construction in Maryland

Maryland has enacted RRNC requirements for new residential construction in Zone 1 counties through adoption of IRC Appendix F in certain jurisdictions. Montgomery, Frederick, Carroll, and other high-radon counties have incorporated RRNC requirements into local building codes. Buyers of new construction in Maryland’s Zone 1 counties should confirm RRNC compliance with the builder and local building department.

Frequently Asked Questions

Does Maryland require radon contractor licensing?

Yes. Maryland has comprehensive state radon licensing for both measurement and mitigation contractors, administered by the Maryland Department of the Environment. Verify license status through MDE before hiring any contractor.

What parts of Maryland have the highest radon?

Western and central Maryland counties — Montgomery, Frederick, Carroll, Baltimore, Harford, Cecil, Howard, and Washington counties — have the state’s highest radon potential, overlying Piedmont and Reading Prong geology.

Does Maryland require RRNC for new homes?

Some Zone 1 Maryland counties have adopted RRNC requirements locally. Verify with your local building department — requirements vary by jurisdiction.

Maryland Radon Data and County-Level Information

The Maryland Department of the Environment publishes county-level radon data from the Maryland Radon Survey and ongoing testing results. MDE’s county data shows that Montgomery County has among the state’s highest average indoor radon concentrations, driven by the Reading Prong granite geology beneath much of the county. Frederick County, Carroll County, and Harford County consistently show elevated averages. The MDE radon program website provides county-level maps and average concentration data for homeowners researching their specific area.

Baltimore Area Radon Risk

Baltimore City and Baltimore County are Zone 1 to Zone 2, with meaningful radon risk throughout the Baltimore metropolitan area. Howard County — which spans the suburban corridor between Baltimore and Washington — is Zone 1. Anne Arundel County (Annapolis area) is Zone 2. The Baltimore metropolitan area’s mix of older housing stock (pre-1980 homes with basement blocks, stone foundations, and minimal sealing) and Zone 1 geology makes testing an urgent priority for Baltimore-area homeowners who have not yet checked.

Maryland Testing Resources

The Maryland Department of the Environment Radon Program provides resources including a certified contractor database, educational materials, and guidance on interpreting test results. Maryland participates in EPA’s State Indoor Radon Grant (SIRG) program, which funds testing assistance and public education. Contact MDE directly for the most current list of licensed Maryland radon contractors and any available test kit assistance programs.

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.