Finding the right radon contractor is not complicated — the verification steps are fast and the credential databases are publicly searchable. The challenge is that the radon industry includes a wide spectrum of practitioners, from highly trained certified professionals following AARST-ANSI standards to uncredentialed handymen offering cheap work that may leave your radon problem partially or completely unresolved. Knowing what to look for — and what to run from — takes about 20 minutes of due diligence and can be the difference between a system that achieves 0.5 pCi/L and one that barely moves the needle.
Step 1: Verify Credentials Before Anything Else
Before you ask about price, timeline, or approach, verify that the contractor holds current radon mitigation certification. There are two ways to do this:
National Certification Verification
- NRPP (National Radon Proficiency Program): Search at nrpp.info by name, company, or zip code. The directory shows current certification status and discipline (measurement, mitigation, or both). Certification that has lapsed appears differently from active certification — confirm the status is current.
- NRSB (National Radon Safety Board): Search at nrsb.org. Same capability — name, company, zip code search with current status display.
Either NRPP or NRSB certification is acceptable. Both are EPA-recognized. A contractor who cannot provide a verifiable certification number from one of these organizations should not be hired for radon mitigation work.
State License Verification
In states with radon contractor licensing requirements (Florida, Illinois, Iowa, Maryland, Minnesota, New Jersey, New York, Pennsylvania, Tennessee, Virginia, and others), the contractor must also hold a current state license in addition to national certification. Verify the state license through your state’s radon program or contractor licensing board. State license databases are searchable online in most states — search for “[your state] radon contractor license lookup.”
Green Flags: Signs of a Quality Contractor
- Conducts a pre-installation diagnostic: A quality contractor drills a small test hole and performs a sub-slab communication test before designing the system — confirming sub-slab aggregate conditions and sizing the fan appropriately. Any contractor who immediately reaches for the core drill without testing is skipping a step that AARST SGM-SF requires.
- Provides a written contract before work begins: The contract should specify the scope of work, the fan model, the number and location of suction points, the post-mitigation testing requirement, the workmanship warranty terms, and the total price. Verbal agreements for radon work create disputes.
- Includes post-mitigation testing in the quote or contract: The installation is not complete until post-mitigation testing confirms results below the target level. A contractor who delivers an installation without a post-mitigation testing plan has not closed the loop.
- Places the fan in unconditioned space: Fan installation in the attic, exterior, or garage — not inside conditioned living space. Any contractor proposing to mount the fan in your basement utility room has not followed AARST SGM-SF.
- Uses PVC primer and cement on all joints: Every joint in the riser pipe should be primed and cemented — visible as a purple/gray ring around the pipe at each connection. Dry-fitted joints are a quality failure.
- Installs a U-tube manometer: Required by AARST SGM-SF. Any installation without a performance indicator is incomplete.
- Provides complete documentation at job completion: A good contractor leaves you with a written report including pre-installation radon level (if you provided a test result), system specifications (fan model, suction point location), their certification/license number, and post-mitigation testing instructions or arrangements.
Red Flags: Signs of an Unqualified or Unscrupulous Contractor
- Cannot or will not provide a verifiable certification number: This is the single most disqualifying factor. No certification number = no verified credentials = no hire.
- Quotes an unusually low price without seeing the home: A legitimate contractor provides a firm quote after assessing the home’s foundation type, sub-slab conditions, and pipe routing requirements. A phone quote of $400 for a job that typically costs $800–$1,500 is a warning sign of cut-rate work, inexperience, or hidden charges that emerge after work begins.
- Proposes installing the fan inside conditioned living space: This violates AARST SGM-SF and creates a radon discharge risk if the fan housing develops a leak. Walk away from any contractor who proposes this.
- Does not discuss or perform sub-slab testing before drilling: Rushing to drill without testing sub-slab conditions suggests either inexperience or disregard for proper installation protocol.
- Offers no post-mitigation testing: “Trust me, it’ll work” is not a professional standard. Any installation without a documented post-mitigation test is incomplete.
- Guarantees a specific post-mitigation level before installing: Legitimate contractors can estimate likely outcomes but cannot guarantee a specific pCi/L result before installation — the actual result depends on sub-slab conditions, sealing quality, and other site-specific factors. Specific guarantees may indicate a contractor willing to say whatever closes the sale.
- Uses spray foam as the sole core hole sealant: Spray foam compresses over time and is not airtight. The annular gap around the riser pipe at the slab must be sealed with hydraulic cement or non-shrink epoxy grout. A contractor who fills the core hole with foam alone is not following best practice.
- Resists providing a written contract: Verbal agreements create disputes. Any legitimate contractor operating professionally will provide a written scope of work and pricing before beginning.
Getting and Evaluating Competing Quotes
Get at least two quotes from verified certified contractors. Comparing quotes requires understanding that price differences may reflect legitimate differences in scope:
- A quote for $1,800 may include pre-installation diagnostic testing, premium fan model, interior routing to the attic, complete slab sealing, post-mitigation testing, and a 3-year workmanship warranty
- A quote for $850 may include a standard fan, exterior routing, basic core hole sealing, and no post-mitigation test
When comparing quotes, ask each contractor to specify:
- Whether a sub-slab diagnostic test is included
- The fan model proposed and why they selected it
- Whether routing will be interior (attic-mounted fan) or exterior (wall-mounted fan)
- Whether post-mitigation testing is included and what type
- The workmanship warranty terms and duration
- What the callback policy is if post-mitigation results don’t achieve target levels
The lowest quote is not automatically the best value — the question is whether the lower-priced contractor is offering a complete installation that will achieve adequate radon reduction, documented by post-mitigation testing.
What a Good Contract Should Include
- Contractor’s name, company, address, phone, and email
- NRPP or NRSB certification number and state license number (if applicable)
- The scope of work: number and location of suction points, fan model, pipe routing (interior vs. exterior), slab sealing scope, manometer installation
- Post-mitigation testing: who conducts it, what device type, what constitutes satisfactory results
- Workmanship warranty: duration, what it covers (typically: callback at no charge if post-mitigation results exceed target level)
- Total price and payment terms
- Liability insurance confirmation
- Estimated installation date and duration
Frequently Asked Questions
How do I find a certified radon contractor near me?
Search the NRPP directory at nrpp.info by zip code to find certified Radon Mitigation Specialists within your area. The NRSB directory at nrsb.org provides the same capability. Your state radon program (searchable as “[your state] radon program”) typically maintains a state-specific list of certified or licensed contractors that may be more current than national directories.
How many quotes should I get for radon mitigation?
At least two from verified certified contractors, ideally three. The market for radon mitigation varies significantly by region — what costs $900 in rural Ohio may cost $1,800 in suburban New Jersey. Three quotes provide enough data to identify outliers in either direction and make an informed selection. All quotes should be written and itemized.
What warranty should a radon contractor provide?
A standard workmanship warranty for radon mitigation covers the contractor’s obligation to return and correct the system at no additional charge if post-mitigation testing results exceed the target level (typically 4.0 pCi/L). Duration ranges from 1 to 5 years depending on the contractor and state. The fan manufacturer (RadonAway, for example) separately provides a 5-year fan warranty covering defective parts. Get both warranty terms in writing before work begins.
Is the cheapest radon contractor the best choice?
Not necessarily. The cheapest quote may reflect a less experienced contractor, cut-rate materials, exterior routing instead of interior (lower labor, but exposed fan), no post-mitigation testing, or a minimal warranty. A complete installation that achieves documented radon reduction is the goal — the price to achieve that goal is the relevant comparison, not the raw quote amount.
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