Radon Contractor Licensing Requirements by State: What You Need to Know

Not all radon contractors are equally regulated. In some states, performing radon mitigation or measurement requires a state license — examination, insurance, continuing education, and annual renewal. In others, there is no requirement at all: anyone can install a radon system or conduct a radon test legally, regardless of training or competence. Knowing which type of state you live in is the first step toward protecting yourself when hiring.

The Spectrum of State Radon Contractor Regulation

State radon contractor requirements fall into several categories:

States with Comprehensive State Licensing Programs

These states have enacted radon-specific licensing statutes requiring contractors to obtain a state license to legally perform radon work. Licensing typically requires:

• Passing a state examination or completing state-approved training
• Demonstrating NRPP or NRSB national certification (some states accept national certification in lieu of a separate state exam)
• Carrying general liability insurance and in some states E&O (errors and omissions) insurance
• Paying a licensing fee and renewing annually or biennially
• Completing continuing education during each license period

States with comprehensive licensing programs (as of 2026) include: Florida, Illinois, Iowa, Kansas, Maine, Maryland, Minnesota, Montana, New Jersey, New York, Ohio, Pennsylvania, Tennessee, and others. Requirements change — verify current status with your state radon program.

States That Accept National Certification as Licensing

Some states do not have separate state licensing requirements but have enacted laws or regulations that require contractors to hold current NRPP or NRSB certification to perform radon work legally. The practical effect is similar to licensing — the national certification serves as the state qualification. States in this category include several that require certification for at least some types of radon work (real estate measurement, school testing, or mitigation work with homeowner contracts).

States with No Radon Contractor Regulation

Roughly half of U.S. states have no radon-specific contractor licensing or certification requirements. In these states, there is no legal barrier to anyone performing radon work — from installation of mitigation systems to conducting real estate radon tests — regardless of training or competence. This does not mean good contractors do not exist in these states; many voluntarily maintain NRPP or NRSB certification. But it means you cannot rely on legal licensing as a screening tool — you must verify credentials directly.

Measurement vs. Mitigation Licensing: Different Requirements

Many states regulate measurement and mitigation separately. A contractor may be licensed for one but not the other:

• Measurement-only licensing: Required for conducting certified radon tests (particularly for real estate), even in states where mitigation has no licensing requirement
• Mitigation-only licensing: Required for installing systems; the contractor may not be authorized to conduct certified post-mitigation measurements
• Dual certification/licensing: Some professionals hold both; many do not — confirm which credential a professional holds before engaging them for a specific service

How to Verify a Contractor’s State License

• Your state health department radon program: The most authoritative source. State radon programs maintain lists of currently licensed contractors and often have an online lookup tool. Search for “[your state] radon program” or “[your state] radon contractor license”.
• NRPP directory: nrpp.info — searchable by name, zip code, or certification number. Shows current certification status and discipline (measurement, mitigation, or both).
• NRSB directory: nrsb.org — same search capability for NRSB-certified professionals.
• Ask directly: Request the contractor’s state license number and national certification number. Ask which certification they hold (measurement, mitigation, or both). A legitimate professional provides this immediately.

What “No State Licensing Requirement” Means in Practice

In states without radon contractor regulation, your protection comes from:

• Voluntarily certified contractors: NRPP and NRSB directories include contractors in unregulated states who have chosen to obtain and maintain national certification. Prioritize these contractors.
• Contract terms: A written contract specifying that installation will follow AARST-ANSI SGM-SF requirements creates an enforceable standard even where licensing does not.
• Workmanship warranty: Reputable contractors in unregulated states typically offer warranties equivalent to those required in licensed states. Get the warranty in writing before work begins.
• Post-mitigation independent testing: Regardless of contractor certification status, placing your own post-mitigation test device independently confirms whether the system is achieving its purpose.

Frequently Asked Questions

Does my state require a licensed radon contractor?

Approximately half of U.S. states require some form of radon contractor licensing or certification. The fastest way to find your state’s specific requirements is to search “[your state] radon program” through your state health or environment department website. Many state radon programs maintain a list of licensed contractors and post current requirements online. Requirements change — information that is two or more years old may be outdated.

Can an unlicensed contractor install a radon system?

In states without radon contractor licensing requirements, yes — legally. In states with licensing requirements, performing radon mitigation without a license is illegal and may void warranty coverage, create liability for the homeowner (if work requires a building permit), and result in a system that does not meet AARST-ANSI standards. Always verify your state’s requirements and the contractor’s credentials before engaging anyone for radon work.

Does a radon contractor need to be licensed to test and mitigate?

Often yes for both activities — but through separate credentials. In most states with licensing, measurement (testing) and mitigation (system installation) are separately licensed or certified. A contractor licensed only for mitigation may not be authorized to conduct the certified post-mitigation measurement. Verify both credentials when a single contractor proposes to both install and certify the post-installation result.