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.
- All homeowner guides — every decision page in one place.
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.
Sources
- U.S. EPA — Radon
- U.S. EPA — A Citizen’s Guide to Radon
- U.S. EPA — Consumer’s Guide to Radon Reduction
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.