How to Choose a Radon Remediation Contractor

Why Contractor Selection Matters for Radon Mitigation

Radon mitigation is one of those home services where the quality of the contractor directly determines the outcome for years to come. A well-designed, properly installed system running a correctly sized fan will reliably keep your home's radon levels below the EPA action level. A poorly executed installation — the wrong suction point location, an undersized fan, insufficient sealing — may not. And since the only way to know if it's working is a post-installation test, a bad result could send you back to square one.

This isn't a project where the lowest bid and a Google search is all the due diligence you need. The good news: choosing a competent, trustworthy radon mitigation contractor is straightforward once you know what to look for. Start with a certified radon test to establish your baseline before contacting any contractors.

The Certifications That Matter: NRPP and AARST-NRPP

The two most important credentials for a radon mitigation contractor are issued by the National Radon Proficiency Program (NRPP), which is administered by AARST-NRPP (the American Association of Radon Scientists and Technologists, National Radon Proficiency Program). These organizations develop and maintain the professional standards for radon mitigation in the United States, including the written examinations and continuing education requirements that certified mitigators must meet.

When evaluating contractors, look for:

• AARST-NRPP Certified Radon Mitigator (CRM): The individual who designs and installs your system should hold this credential or an equivalent state-issued certification. It means they have passed a standardized examination and demonstrated competency in mitigation system design and installation.
• State licensing: Some states require radon contractors to carry state-issued licenses in addition to national certification. North Carolina homeowners should verify whether their contractor meets any applicable state requirements.
• Verification: Both NRPP and AARST maintain searchable online databases where you can verify a contractor's certification status. Don't just take their word for it — a quick search takes two minutes and confirms you're working with someone whose credentials are current.

Questions to Ask Before You Hire

Once you've confirmed a contractor is certified, the conversation shifts to the specifics of your project. Here are the questions worth asking before signing anything:

"Will you perform a diagnostic before installation?"

A proper mitigation installation begins with a diagnostic assessment — including a suction point test to evaluate soil permeability beneath your slab and identify the best location for suction. Contractors who skip this step and go straight to drilling are guessing at system design rather than engineering it. This single question filters out a lot of substandard operators.

"How will you route the pipe, and why?"

Ask the contractor to walk you through their planned pipe route — where it enters the slab, how it exits the house, and where the fan will be located. An interior route (through the house and up through the roof) is often more aesthetically clean; an exterior route is simpler and typically faster. Either can be done well. The point is that a competent contractor has a clear rationale and can explain the tradeoffs.

"What fan will you install, and how did you select it?"

Fan selection should follow from the diagnostic — soil permeability, suction point count, and the length and diameter of the pipe run all factor in. If a contractor gives you a single answer without asking about your foundation first, they're not sizing the system properly.

"Does your quote include post-installation testing?"

A contractor who stands behind their work includes a post-installation test to confirm the system is performing. This test should happen under closed-house conditions, typically 24 hours after installation. Confirm it's included in the quote — and then schedule an independent post-mitigation verification test with a certified testing professional to get a second, documented result.

"What's your warranty on workmanship and the fan?"

Reputable contractors offer a workmanship warranty (typically one to three years on the installation) and pass through the fan manufacturer's warranty (usually five years). If a contractor offers no warranty, that's a meaningful signal about how they stand behind their work.

"Can you provide references from similar projects?"

Ask for two or three references from homeowners with similar foundation types who had their systems installed in the past year or two. A contractor who has been doing this work in your area will have no difficulty producing them.

Red Flags to Watch For

Most radon contractors are honest professionals. But some warning signs are worth knowing:

• No certification or reluctance to show credentials: A certified contractor will readily share their NRPP certificate or license number. Hesitation here is disqualifying.
• No diagnostic step: Drilling without testing soil permeability first is a sign the contractor is following a script rather than designing a system for your specific home.
• No post-installation test included: This is standard practice. Omitting it suggests the contractor isn't planning to verify their own work.
• Pressure tactics or artificially urgent timelines: Radon mitigation is a planned project, not an emergency. A contractor who creates urgency to close a sale is more interested in the transaction than the outcome.
• Significantly below-market quotes: If one bid is dramatically lower than the others, ask why. It may reflect fewer suction points than your foundation requires, a smaller fan than the diagnostic calls for, or simply cut corners on materials and labor time.
• No written contract: Get the scope, price, warranty, and timeline in writing before work begins. A contractor who resists this is a contractor to avoid.

Getting Multiple Quotes

For a project in the $900 to $1,500 range, getting two or three quotes is worthwhile. It gives you a sense of local pricing, lets you compare proposed approaches, and identifies any significant outliers. When comparing quotes, look at what each one includes — suction point count, fan specification, pipe routing, and post-installation testing — not just the total price.

Once your system is installed, remember that an independent post-mitigation verification test from a certified testing professional gives you a separate, documented result that confirms your home is protected — and that you're not simply taking the contractor's word for it. If you're in Kannapolis, Concord, or Landis, Wightman Inspection Group provides exactly this kind of independent, certified verification.

For context on why this work requires a licensed professional rather than a DIY approach, see the next article in this series.