How to choose a radon mitigation contractor

Step one: confirm the credential that actually applies

Radon work is a licensed specialty in some states and a nationally certified one in others, and general contractor licensing is not a substitute for either. Ask for the credential number, confirm it is current, and confirm it covers mitigation rather than measurement alone — those are separate credentials nearly everywhere, and a firm may legitimately hold one without the other.

Where a state issues its own license, that is the one to verify. Where it does not, the national proficiency programs fill the gap, and a current NRPP or NRSB certification is the meaningful signal. Either way, verify it yourself rather than accepting a logo on a vehicle or a badge on a website.

Step two: insist on a diagnostic before a price

The central engineering question in any mitigation job is whether suction applied at one point beneath the slab reaches across the whole floor. That is answered by a pressure-field test — a small test hole, applied suction, and measurements taken at points across the slab — not by looking at the square footage.

A contractor who has run that test can tell you how many suction points your house needs and why. One who has not is estimating from the floor plan, and the risk lands on you: an undersized design runs for years, makes noise, costs electricity, and moves the number far less than it should.

Step three: get the design in writing before the price matters

A complete quote is a description of a system, not a number with a company name on it. It should name the suction point count and locations, the routing path, the fan by make and model with its mounting location, the sealing scope, who handles electrical, warranty terms and duration, and the post-mitigation verification test.

Once you have two or three of those documents side by side, comparison becomes straightforward. Bids that look wildly different usually turn out to describe different amounts of work, and the cheaper one is frequently quoting a smaller job rather than the same job for less.

• Suction point count and where each one goes
• Pipe routing — interior chase, exterior wall, or attic — and where the discharge terminates
• Fan make and model, and where it is mounted (never inside conditioned space)
• Sealing scope: floor-wall joint, slab penetrations, sump lid, and any block wall treatment
• Who pulls electrical, and whether a permit is included
• Warranty: what covers the fan, what covers workmanship, and for how long
• The post-mitigation verification test, priced in rather than offered as an extra

Step four: make the verified result the deliverable

A running fan proves a fan is running. Only a post-mitigation measurement, taken after the system has operated for at least twenty-four hours and placed where the original detector sat, proves the concentration came down.

Ask for that number in writing with the credential on the same document, and keep it. It is what answers a future buyer, a future tenant, or a future inspector without paying for another test — and it is the one piece of paper that tells you the money did what it was supposed to do.