Radon Regulations in the United States: How State Laws Differ

In the United States, radon regulation is defined by a striking contrast: while federal public health agencies establish scientific risk baselines and national testing benchmarks, legal authority to mandate testing, mitigation, or building standards rests entirely with state and local jurisdictions. Because the federal government imposes no universal radon mandate on private residential property, homeowners, home buyers, and real estate professionals must navigate a fragmented patchwork of state statutes, health department administrative rules, and municipal building codes.

The Federal EPA Framework

The foundation of U.S. radon policy was codified under the Indoor Radon Abatement Act of 1988 (15 U.S.C. §§ 2661–2671), which established the long-term national goal that indoor air across the United States should be as free of radon as ambient outdoor air (approximately 0.4 picocuries per liter of air, or pCi/L). To provide actionable guidance for property owners and policymakers, the U.S. Environmental Protection Agency (EPA) established a national recommended action level of 4.0 pCi/L. If indoor radon levels meet or exceed 4.0 pCi/L, the EPA strongly advises installing an active soil depressurization or mitigation system; for levels between 2.0 and 4.0 pCi/L, the agency suggests considering mitigation to further reduce lung cancer risk.

To assist national, state, and local governments in targeting resources and adopting building codes, the EPA developed the Map of Radon Zones, categorizing every county in the nation into three risk categories:

• Zone 1 (High Potential): Predicted average indoor screening levels greater than 4.0 pCi/L.
• Zone 2 (Moderate Potential): Predicted average indoor screening levels between 2.0 and 4.0 pCi/L.
• Zone 3 (Low Potential): Predicted average indoor screening levels less than 2.0 pCi/L.

Crucially, federal law establishes guidelines, technical protocols, and state indoor radon grant funding, but creates no federal requirement for individual homeowners to test or mitigate existing dwellings. For detailed geographical analysis of county risk tiers across the nation, consult our EPA Radon Zone Map guide.

Four Dimensions Where State Laws Differ

Because federal oversight ends with advisory guidelines, states have legislated radon risk across four distinct regulatory dimensions:

1. Real Estate Disclosure Laws

Real estate transactions represent the most common commercial pressure point for radon testing. State disclosure laws fall into three general categories:

• Statutory Awareness Acts: States like Minnesota (Minn. Stat. § 144.496) and Colorado (SB 23-206) require sellers (and in Colorado, residential landlords) to provide formal written disclosure forms, distribute official state health department educational publications, disclose all historical test records, and incorporate statutory health warning statements into contracts before execution.
• Standard Property Condition Disclosures: States such as Nebraska (Neb. Rev. Stat. § 76-2,120), New Jersey, and Washington (RCW 64.06.020) include specific radon questions on mandatory property condition statements, obligating sellers to disclose known test data or installed mitigation systems.
• Caveat Emptor / Common Law States: States like Massachusetts and Georgia lack radon-specific disclosure statutes, relying instead on common-law prohibitions against active fraud or concealment of known material latent defects, leaving testing to purchase contract inspection contingencies.

2. Mitigator and Tester Credentialing

Consumer protection standards for commercial radon professionals vary widely across state lines:

• Independent State Licensing Boards: States including Minnesota (MDH), New Jersey (NJDEP), Colorado (DORA), Florida (FDOH), and Nebraska (DHHS) mandate comprehensive state licenses or certifications. In these states, performing measurement, mitigation, or laboratory analysis for compensation without an active state credential is a statutory violation. Minnesota further mandates that every installed system carry a serialized state tracking tag.
• Statutory National Board Adoption: Virginia (Va. Code § 32.1-229.01) makes commercial testing or mitigation unlawful without active proficiency certification from national boards—specifically the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB)—without maintaining an independent state credentialing bureaucracy.
• Voluntary / Unregulated States: Jurisdictions such as Massachusetts, Washington, and Georgia operate no state credentialing programs, directly pointing consumers and building officials to the NRPP and NRSB national rosters.

3. Institutional and School Testing Mandates

While testing in existing single-family homes is universally voluntary for private owners, several states mandate routine monitoring in sensitive institutional facilities:

• Mandatory School and Childcare Testing: Florida (F.S. § 404.056) mandates testing across all public/private K-12 schools, state-licensed daycares, and 24-hour care facilities in designated counties. New Jersey (N.J.S.A. 18A:20-40) mandates testing in public school buildings and licensed child care centers every five years. Virginia (Va. Code § 22.1-138) mandated historical baseline testing of all public schools with ongoing reporting to the health department.
• Voluntary School Frameworks: In Minnesota, Nebraska, Colorado, Massachusetts, Washington, and Georgia, testing in existing school buildings is conducted voluntarily by local school boards, often utilizing state health department grants or national ANSI/AARST testing protocols.

4. Radon-Resistant New Construction (RRNC) Building Codes

Radon-resistant new construction techniques—such as passive soil-gas collection layers, vapor retarders, vertical PVC vent pipes, and sealed foundation perimeters—are enforced through building code adoptions:

• Statewide Mandatory RRNC: Minnesota mandates passive radon control statewide across all new residential construction via Minnesota Statutes § 326B.106 and International Residential Code (IRC) Appendix F. Nebraska mandates passive RRNC in new residential and educational buildings built after September 1, 2019 (Neb. Rev. Stat. § 76-3501).
• County-Specific / High-Risk Mandates: Massachusetts (780 CMR Appendix F) enforces mandatory passive RRNC strictly within EPA Zone 1 counties (Essex, Middlesex, and Worcester). Washington (WSRC Appendix F) mandates passive RRNC across seven designated Zone 1 counties. New Jersey (N.J.A.C. 5:23-10) enforces the Radon Hazard Subcode in designated Tier 1 municipalities.
• Locally Adopted or Voluntary Codes: In Virginia and Georgia, RRNC enforcement depends on local municipal code adoptions or voluntary builder adherence to EPA architectural standards.

State Radon Laws: Wave 2A Comparison Table

The table below summarizes the core statutory mechanisms, credentialing standards, and disclosure rules across the top nine state jurisdictions evaluated in Wave 2A. Click any state guide for complete statutory citations, administrative rules, and state program contacts.

Accessing Official State Programs and Test Kits

Every state health department maintains a designated radon program or radiation control coordinator supported by federal State Indoor Radon Grants (SIRG). Residents seeking to test their dwellings can obtain subsidized, low-cost short-term and long-term test kits directly through state health agency links or authorized university extension services. Property owners seeking professional mitigation should independently verify contractor credentials through either their state licensing division (in mandatory licensing states) or via the official registries maintained by the National Radon Proficiency Program (NRPP) and the National Radon Safety Board (NRSB).

For additional architectural and geological context on how soil gas potential impacts local property values and building performance, consult our national EPA Radon Zone Map.

Sources & Limits

This regulatory hub is provided for informational purposes only and does not constitute formal legal, real estate, or engineering advice. Statutory disclosure requirements, professional licensing standards, and building codes vary by state and local municipality and are subject to legislative amendment. Property buyers, sellers, landlords, and contractors should verify current rules directly with their respective state health department radon programs or qualified legal counsel.

Primary Official Sources: U.S. Environmental Protection Agency (Indoor Radon Abatement Act, 15 U.S.C. §§ 2661–2671; EPA Map of Radon Zones), Centers for Disease Control and Prevention (CDC), and official state health department radon programs across all fifty states.