Red Flags in a Radon Mitigation Quote

A bad radon mitigation quote isn't always obviously bad. Sometimes it looks professional, the price is reasonable, the contractor is friendly — and the quote is still missing the things that would prove the system is going to work. This page is the field guide to what to walk away from.

If any one of these is true, do not sign the quote. Period.

• No DORA radon mitigation license number on the quote. Colorado has required this since July 1, 2022. No exceptions.^[1]
• No NRPP or NRSB certification number. National professional credential. Required per CDPHE guidance.
• Cash-only payment. Reputable contractors accept check or card.
• No written quote. Verbal promises don't bind anyone.
• Refuses to provide proof of liability insurance or workers' comp. Means you bear the legal risk.
• Won't provide references. Or "I'd love to but my customers value their privacy" with no other options offered.

These should prompt clarifying questions. If the answers are good, you can proceed. If the answers are vague or evasive, walk away.

Sales-tactic red flags

• "This price is only good today." Mitigation isn't a same-day-only purchase. Anything legitimate can wait two days.
• Fear-based language. "Your family is in danger" or "if you don't act now" is pressure, not education.
• Aggressive door-to-door sales. Some legitimate contractors do canvass, but cold-call door-to-door radon sales after a high test is suspicious.
• "Special pricing if you sign today." Same family as the urgency tactic.

Scope red flags

• Single suction point on a multi-zone home (tri-level, split-level, basement + crawlspace). Should have at least two. Ask why.
• No fan model specified. "An inline fan" isn't a fan model. Should be a specific RP145, GP500, HS-series, etc.
• "We always use the standard fan." Colorado altitude affects fan sizing. A one-size-fits-all answer is a contractor who isn't designing for your home.
• Pipe routing not described. Should say interior or exterior, and where it exits.
• No discussion of sealing. Sealing scope (slab cracks, sump cover, floor-wall joint, penetrations) should be itemized.
• 6-mil vapor barrier for a crawlspace. Old standard. Current industry favors 10–20 mil. Ask why if 6 mil is proposed for a permanent system.
• Post-mitigation test not included. Or listed as "additional cost" without a price. Ask. Some contractors charge $125–$200 separately, which is fine if disclosed.

Warranty red flags

• Workmanship warranty under 1 year. Industry standard is 1–2 years minimum.
• No fan warranty mentioned. Should be 5 years from a name-brand manufacturer.
• No performance warranty. No commitment that the system will bring radon below 4.0 pCi/L.
• Warranty language that voids itself for normal usage. "Warranty void if homeowner opens basement windows" or similar.

Pricing red flags

• Suspiciously low for your scenario. $700 for a crawlspace, $1,200 for multi-zone tri-level. Something's not in the scope.
• Suspiciously high for your scenario. $4,500 for a basic single-suction basement install. Ask what's driving it.
• "Required upgrades" the contractor can't explain. Especially if they appear as line items without technical justification.
• Large deposit (>50%). Industry standard is 25–50% deposit. Anything more is unusual.

These warrant a question but aren't necessarily disqualifying:

• Contractor is brand new (less than 2 years). Some are excellent; some are problematic. Ask for references from comparable jobs.
• BBB rating under A-. Look at the complaint pattern and the contractor's response.
• Mixed online reviews. Read negative reviews carefully and look at the contractor's response.
• Very high pricing in an expensive scenario. A $4,500 quote for a complex crawlspace + multi-zone home may be entirely fair.
• Exterior-only routing proposed. Some homeowners prefer interior; both are AARST-compliant. Ask if interior is an option and what it costs.

1. Ask directly. A good contractor explains. A bad one gets defensive or vague.
2. Compare against another quote. If the second contractor's quote includes what the first one's was missing, you have your answer.
3. Document the conversation. Especially if a contractor says one thing verbally but their written quote says another.
4. Walk away if you need to. There are plenty of DORA-licensed mitigators in Colorado. You're not stuck with the first bid.