Radon mitigation in Denver metro

Last updated: 2026-09-08 · 8 min read · City hub

Denver, Boulder, Fort Collins, Colorado Springs, and much of the Front Range sit in geology that often produces elevated indoor radon. Colorado public-health messaging has long treated testing as routine — not optional. This hub covers what mitigation usually looks like locally, what it tends to cost, and how to hire without guessing.

What you’ll learn

• Why Front Range homes frequently need mitigation after a test
• What an active soil depressurization (ASD) system typically includes
• Ballpark cost ranges and what drives quotes up or down
• Questions to ask a Colorado mitigator before you sign

Why Denver-area homes test high so often

Much of Colorado is EPA Zone 1 (predicted average screening levels above 4 pCi/L at the county scale). That does not mean every Denver house is above 4 — it does mean elevated readings are common enough that buyers, sellers, and inspectors treat radon as a standard due-diligence item.

Basements are common on the Front Range. Lived-in basements are exactly where short-term tests are usually placed, so results often reflect the highest occupied level. New construction with radon-resistant features helps, but finished older basements without a system still need a real measurement.

What mitigation usually means here

Most Denver-metro installs are active soil depressurization: a sealed suction point under the slab or in a sump, PVC piping, and an inline fan that vents above the roof. Crawlspace homes may need soil-gas collection membranes. Homes with both slab and crawl areas often need combined approaches.

1. Confirm an elevated test (DIY short-term or certified continuous monitor).
2. Mitigator inspects foundation type, sump, HVAC, and possible pipe routes.
3. System install (often same day or within a few days for standard ASD).
4. Post-mitigation retest — do not skip this step.

Start with a good measurement: see our short-term test kit compare if you are screening first.

Typical cost ranges (planning estimates)

US consumer guidance and Colorado contractor quotes commonly land in roughly $800–$2,500 for a straightforward ASD on a single-family home; complex foundations, multi-suction points, or difficult fan placement can run higher. Treat these as planning bands — get written local quotes.

• Lower end — accessible basement, existing sump usable as suction point, short exterior chase
• Mid range — slab drill + interior or exterior riser, standard fan, manometer
• Higher — large footprint, addition/crawl combo, aesthetic routing, electrical upgrades

Ask whether the quote includes the post-mitigation test, permit fees (where required), and fan warranty terms.

Hiring checklist (Denver metro)

• NRPP or NRSB mitigation credential (and any Colorado / local licence requirements that apply to the contractor)
• Proof of insurance; written scope with suction points and fan location
• Expected post-mitigation target (often well below 4 pCi/L)
• Fan replacement cost and typical lifespan (often ~5–10+ years depending on model)
• Whether they retest or you hire an independent tester

Browse RadonFind listings for testers and mitigators. Featured or referral placements will be labelled when used.

Neighborhoods and nearby cities this hub covers

Use this page as the metro entry point for Denver proper, Aurora, Lakewood, Arvada, Westminster, Thornton, Centennial, Boulder County buyers commuting in, and similar Front Range ZIPs. City-specific contractor density varies; always verify credentials for the address being mitigated.

FAQ

Is radon mitigation required to sell in Denver?

Requirements depend on contract language and lender expectations more than a single city ordinance. Many Colorado purchase contracts include a radon contingency. Sellers often mitigate to keep a deal moving when levels are elevated.

Will a system ruin my finished basement look?

Good installs hide pipe runs along utility walls or chase them outdoors. Ask for a routing sketch before work starts if aesthetics matter.

How soon can I retest?

Follow the mitigator’s protocol and EPA-style short-term timing — often after the system has run continuously for at least 24 hours (many pros prefer a full short-term window). Keep closed-house conditions during the retest.

Related guides

• Short-term radon test kit compare
• EPA zone maps explained
• Radon testing in Columbus, OH
• Radon mitigation in Philadelphia

Disclosure: RadonFind may earn commissions from test-kit affiliates or mitigator referrals when labelled. Cost figures are estimates, not quotes. Confirm current Colorado health-department and EPA guidance before you buy or install.