Questions to ask before you hire a radon contractor
Most homeowners ask about price and availability, get two answers that sound alike, and pick the cheaper one. The questions below do something different: they surface what each contractor actually intends to build, which is where the real difference between bids lives.
You do not need to be technical to ask them. You need to notice which contractor answers specifically and which one answers in generalities.
About the diagnosis
These establish whether the bid is based on your house or on an average house. A contractor who has run a pressure-field test will answer without hesitation and will usually volunteer what they found.
- Did you run a pressure-field test, and what did it show?
- How many suction points does the design use, and what told you that number?
- Is there aggregate under my slab, or is it sitting on native soil?
- Which soil-contact areas does this system cover — and are there any it does not?
About the system itself
These questions get you the specification. Fans are not interchangeable: a fan sized for a permeable gravel bed behaves very differently on a tight slab, and the model number tells an informed reader most of what they need to know.
- What fan make and model, and where will it be mounted?
- Where exactly will the pipe run, and where does the discharge terminate?
- What sealing is included — floor-wall joint, cracks, penetrations, sump lid?
- Will a manometer be installed where I can read it?
About the paperwork and the outcome
This is the group most homeowners skip, and it is the group that decides what happens if something goes wrong six months from now.
- What is your mitigation credential number, and is it current?
- Is the post-mitigation verification test included in this price?
- What does the warranty cover — the fan, the workmanship, or a result — and for how long?
- What happens if the post-mitigation number is still above the action level?
- Who is responsible for the electrical work and any permit?
- How long will the job take, and will the same crew do all of it?
How to read the answers
Specificity is the signal. "We usually put one point in the sump and run it up the outside" is a description of a habit; "your sump has a tile loop, the test showed influence out to the far wall, so one point at the pit does it" is a description of your house.
Hesitation on the warranty and verification questions is worth noticing too. A contractor who prices the verification test as standard is telling you they expect to pass it. One who treats it as an optional add-on has quietly moved the risk onto you.
Questions to ask before hiring: common questions
What if a contractor will not give a written scope before a deposit?
That is a reason to keep looking. A written scope costs the contractor nothing except the honesty of committing to a design, and every established mitigation firm produces one routinely. A deposit paid against a verbal description leaves you with no way to say the work was not what you agreed to.
Is it rude to ask for the credential number?
No, and professionals expect it. In licensed states it is a public record, in certified states the proficiency programs maintain listings, and any contractor who does this work regularly hands over the number without being asked twice. Reluctance is itself an answer.
How much of this matters if my reading is only slightly elevated?
All of it, because the system you install is the same either way. A borderline reading changes whether you act, not how the work should be done. If you decide to mitigate, a poorly designed system at 4.5 pCi/L wastes exactly as much money as a poorly designed system at 20.
Keep reading
- How to choose a radon contractor — The four-step screen: credential, diagnostic, written design, verified result.
- Comparing radon contractors — Compare scopes, not totals. Most bid gaps are scope gaps.
- Warranty questions — What the warranty covers, for how long, and what triggers a claim.
- Understanding installation quality — What to inspect before the crew leaves, in plain language.
- Contractor Response Time Dataset — Instrument published, N = 0. Measured from real routed requests once intake is live.
- Licensing change mid-project — Open quote, scheduled install, or pending verification — how a regime change lands on each.
- All homeowner guides — every decision page in one place.
- Editorial policy — the standards this page was reviewed against.
Ask the diagnostic questions first. If a contractor cannot describe what is under your slab, the rest of the conversation is about a house nobody has actually looked at.
Confidence and limits of this page
Every decision resource on this platform states its own boundaries. This is not a disclaimer — it is the part of this guide you should read before relying on it.
- What we knowClaims on this page we stand behind, each traceable to an approved source or to observable structure.
- Published mitigation guidance describes the diagnostic step, the system families, and the post-installation verification that a competent job includes.
- Proposals for the same house commonly differ in scope, verification, and warranty rather than only in price, which is why aligning them line by line changes conclusions.
- A credential can be confirmed with the authority that issued it, and that confirmation is free and takes minutes.
- What we do not knowQuestions you may reasonably have that this page does not answer.
- Whether any specific contractor is competent. Credential verification establishes a floor, not a standard of work, and we hold no performance observations on individual firms.
- What a job in your market will be quoted at, because this platform has collected no pricing observations of any kind.
- What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
- Recorded proposal-to-outcome pairs across many jobs, which would show which proposal features actually predict a working system.
- Post-installation results matched to the diagnostics performed, which is the evidence that would let anyone rank design decisions rather than describe them.
- What we do not claimClaims you might expect to find here and will not, with the reason.
- We do not rank, score, rate, or recommend individual contractors anywhere on this platform, and no page here names a best company.
- We do not publish a price, an average, or a range, because we have measured none and every such figure would be invented.
- We do not claim a credential guarantees quality of work; it establishes a verified minimum and nothing further.
- What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
- Whether a named individual holds a credential at the moment you ask, which changes over time and only the issuing authority can confirm.
- Any contractor own claims about crew size, years in business, or job counts, none of which appear on this platform as facts.
Put these questions to real contractors
One request routes to up to three independent licensed mitigation contractors serving your ZIP. Ask all of them the same questions and compare the answers.
Sources
- U.S. EPA — Radon
- U.S. EPA — A Citizen’s Guide to Radon