NRPP vs NRSB Certification: What Homeowners Should Know

You are hiring a radon contractor, and their website says they are "NRPP certified." The next company says "NRSB certified." Are these the same thing? Does one matter more? And how do you actually verify any of it?

What Are NRPP and NRSB?

Both organizations exist to certify radon professionals — people who test for radon and people who install mitigation systems. They share a common origin but operate independently.

NRPP (National Radon Proficiency Program) was originally administered by the EPA. When the EPA stepped back from direct administration, NRPP moved under AARST (the American Association of Radon Scientists and Technologists), which is the main professional body for radon science in the United States. NRPP is now managed by AARST-NRPP and remains the most widely recognized radon certification in the country.

NRSB (National Radon Safety Board) was established as an independent certification body, also rooted in the AARST community. It provides a parallel credentialing path with its own exam, continuing education requirements, and professional standards.

A bit of context: the split happened partly over governance and administrative disagreements, not over technical standards. Both programs test practitioners on the same core body of knowledge — EPA protocols, ANSI-AARST measurement and mitigation standards, and state-specific regulatory requirements.

Certification Types

Both NRPP and NRSB offer credentials in two primary areas:

• Radon Measurement. This certifies a professional to conduct radon testing — placing and retrieving devices, interpreting results, and following proper measurement protocols. Both short-term and long-term testing fall under this credential.
• Radon Mitigation. This certifies a professional to design and install radon reduction systems — sub-slab depressurization, sub-membrane systems, and related approaches. Mitigation certification typically requires more training hours and a separate exam.

Some contractors hold both measurement and mitigation certifications. Others specialize in one or the other. When hiring, make sure the contractor's credential matches the service you need. A measurement-only certification does not qualify someone to install a mitigation system.

Which States Require Which?

This is where it gets complicated. Radon contractor licensing is handled at the state level, and there is no national uniformity.

• Some states require NRPP specifically. Their licensing boards reference NRPP certification as a prerequisite for issuing a state radon license.
• Some states accept either NRPP or NRSB. As long as the contractor holds one valid national certification, the state will issue a license.
• Some states accept other credentials or have their own state-run certification programs that may reference but not require national certification.
• Some states have no radon licensing requirement at all. In those states, national certification is voluntary — which makes it even more important to verify, because anyone can claim to be a radon professional.

Before hiring, check your state's environmental or health department website for radon contractor requirements. This tells you what certification is legally required where you live. We explain how we handle this verification across our platform on the methodology page.

Are They Equivalent?

For practical purposes, yes. Both NRPP and NRSB require:

• Passing a proctored exam covering EPA radon measurement and mitigation protocols
• Meeting minimum education and experience thresholds
• Completing continuing education credits for renewal
• Adhering to a code of ethics and professional standards

The technical knowledge tested is substantially the same because both programs are built on the same EPA and ANSI-AARST standards. A contractor certified through NRSB is not less qualified than one certified through NRPP, or vice versa.

What does matter is whether the certification is current. Both programs require periodic renewal with continuing education. An expired certification means the contractor has not maintained their credential, regardless of which program issued it.

How to Verify a Contractor's Certification

Both programs maintain searchable online directories:

• NRPP: Search the AARST-NRPP database by name, state, or certification number. The listing shows certification type, expiration date, and scope.
• NRSB: Search the NRSB directory the same way. Active certifications display the credential type and valid-through date.

When a contractor gives you their certification number, look it up. It takes 30 seconds. If they hesitate to provide it, that tells you something. Our guide to choosing a radon contractor includes this as one of the first screening steps.

What This Means for You as a Homeowner

The short answer? Do not get hung up on NRPP vs. NRSB. Focus on these things instead:

• Is the certification current? Check the expiration date in the directory.
• Does it match the work? Measurement certification for testing, mitigation certification for system installation.
• Does the contractor meet your state's specific requirements? Some states layer their own license on top of national certification.
• Can they provide references and documentation? Certification is the floor, not the ceiling. A good contractor also has a track record of successful installs and post-mitigation test results below 4.0 pCi/L.

The EPA has consistently recommended that homeowners hire certified radon professionals, without favoring one program over the other. Both exist to protect consumers from unqualified work, and both accomplish that goal.

For background on why radon matters in the first place, our guide to radon covers the health science and EPA recommendations. And when you are ready to find verified contractors in your area, our directory shows certification status upfront so you can compare before you call.