Statewide Colorado Realtor Resources
Colorado Real Estate Radon Resources
Statewide radon testing and mitigation support for Colorado realtors, brokers, and MLS members. Closing-timeline turnarounds, Colorado law disclosure compliance, and NRPP-certified partner contractors across 14 Colorado cities.
Colorado Radon Disclosure Law for Real Estate Transactions
Colorado SB 23-206 governs residential radon disclosure. Sellers must provide a radon disclosure and the EPA radon brochure to buyers; landlords must also disclose radon to tenants (since Aug 2023). While Colorado does not mandate pre-sale testing, the Colorado Association of REALTORS (CAR) and the Denver Metro Association of REALTORS (DMAR) both recommend radon testing as standard real estate transaction practice given Colorado's high indoor radon levels.
Key disclosure requirements under Colorado law:
- If radon testing has been performed at the property, the seller must disclose the date and result.
- If a radon mitigation system is installed, the seller must disclose the installation date and any recent verification testing.
- Sellers cannot legally withhold radon information they possess about the property.
- The penalty for failing to disclose known radon issues includes potential rescission of the sale and damages.
Colorado Association of Realtors recommends including a radon contingency clause in every Colorado Real Estate Purchase Agreement, allowing buyers to: (1) conduct radon testing during the inspection period, (2) require seller mitigation if results exceed 4 pCi/L, (3) negotiate cost responsibility, and (4) terminate the agreement if mitigation cannot be completed within the closing timeline.
ALA Risk Framework · Use in disclosure conversations
Source: American Lung Association Healthcare Provider Decision Support Tool (2024) + EPA A Citizen's Guide to Radon (EPA 402/K-12/002). Smoker-radon risk is multiplicative (~9× non-smoker risk at each exposure level) due to synergistic effect between tobacco-related lung damage and alpha-particle radiation from radon decay products.
The American Lung Association Risk Framework — A Realtor's Disclosure Tool
Colorado SB 23-206 requires disclosure of known radon results — but the legal floor is only half the story. The American Lung Association (ALA) maintains the most-cited residential radon risk framework in the United States, and Colorado realtors who can speak to ALA's risk model in a disclosure conversation move buyers from "should I worry?" to "let's address it" faster than any other tool.
ALA Lifetime Lung Cancer Risk by Radon Exposure
The ALA Healthcare Provider Decision Support Tool (2024) models lifetime lung cancer risk from chronic radon exposure for both non-smokers and current smokers, by radon level. The data below — sourced from ALA + EPA — is the framework realtors can cite when a buyer asks "is 4 pCi/L really that bad?"
| Indoor radon (pCi/L) | Never-smoker lifetime risk | Smoker lifetime risk | ALA / EPA recommendation |
|---|---|---|---|
| 1.3 (US avg) | ~2 in 1,000 | ~20 in 1,000 | No action required |
| 2.0 | ~4 in 1,000 | ~32 in 1,000 | Consider mitigation (esp. smokers / children) |
| 4.0 (EPA action level) | ~7 in 1,000 | ~62 in 1,000 | Mitigate — install active radon system |
| 8.5 (Colorado state avg) | ~15 in 1,000 | ~120 in 1,000 | Urgent mitigation |
| 10.0 | ~18 in 1,000 | ~150 in 1,000 | Urgent mitigation; consider interim ventilation |
| 20.0+ | ~36+ in 1,000 | ~260+ in 1,000 | Emergency mitigation; limit time in affected levels |
How to frame a radon disclosure conversation with a buyer or seller
The ALA framework gives realtors a defensible, third-party-authority script for radon-disclosure conversations. Three usage patterns:
- For sellers with elevated test results: "Colorado law requires you to disclose this reading. The ALA risk model says a never-smoker at this level has [X in 1,000] lifetime lung cancer risk attributable to radon, and the EPA recommends mitigation. Pre-listing mitigation typically costs $1,000-$2,800 and converts the disclosure from a sale-killer to a sale-accelerator — verified-mitigated homes close faster and at full price."
- For buyers facing an elevated inspection result: "This is a routine Colorado transaction issue. The ALA framework places a 4.0 pCi/L home at 7-in-1,000 lifetime risk for non-smokers, and the EPA recommends mitigation as soon as practical. We have NRPP + CDPHE-certified partner contractors who can install + verify within the 7-14 day window most contingencies allow. Most Colorado sellers cover this cost."
- For sellers considering whether to pre-test before listing: "Colorado is among the highest-radon states. The ALA framework predicts ~1 in 2 Colorado homes will test elevated. Pre-testing surfaces the issue under your control rather than under buyer-side closing pressure — a pre-mitigated home with verified post-test documentation typically closes faster and at higher price than a home with an elevated test result mid-transaction."
ALA radon resources: lung.org/radon · ALA Colorado: lung.org/ia · EPA A Citizen's Guide to Radon: epa.gov/radon
Colorado Real Estate Radon Transaction Timeline
Standard Colorado transaction timeline from initial test through verified post-mitigation result, designed to fit within most inspection contingency windows.
| Day | Step | Who | Duration |
|---|---|---|---|
| Day 0 | CRM deployed at property during home inspection | Inspector / mitigation specialist | Instantaneous |
| Day 2-4 | Test retrieval + result reporting | Inspector / mitigation specialist | 48-96 hr test period |
| Day 4 | Result review — elevated (>4 pCi/L) triggers mitigation | Realtor + buyer + seller | 1 day |
| Day 5-7 | On-site assessment by NRPP-certified mitigator | Partner contractor | 1-2 hr visit |
| Day 7-9 | Written quote provided + cost negotiation | Realtor + buyer + seller | 2-3 days |
| Day 9-12 | Mitigation system installed | Partner contractor | 4-8 hours on-site |
| Day 13-16 | Post-mitigation verification test | Partner contractor | 48-96 hr test |
| Day 16 | Verification result + final documentation | Partner contractor | 1 day |
| Day 16+ | Closing proceeds with verified mitigation | Closing agent | Per contract |
Services We Provide to Colorado Realtors
- Pre-listing radon testing — Recommend to sellers before MLS listing to surface and mitigate radon issues upfront. Avoids mid-transaction surprises.
- Pre-purchase radon testing — Buyer-side testing during inspection contingency period. CRM-based for transaction-grade documentation.
- Closing-timeline mitigation — Expedited 7-14 day install + verification turnaround. Designed for active transactions.
- Existing system verification — Confirms that a previously-installed radon mitigation system is still maintaining indoor radon below 4 pCi/L. Standard practice for transfers of homes with existing systems.
- FHA / USDA / VA loan compliance documentation — Test reports and verification documentation in lender-acceptable formats.
- New construction RRNC consulting — Colorado builder coordination on Radon-Resistant New Construction features per Colorado builder code recommendations.
- Multi-property portfolio testing — Colorado property managers, REIT, and rental portfolio owners.
Colorado MLS Coverage Areas
Colorado Radon Experts partner network serves the major Colorado MLS regions:
- Colorado Association of REALTORS® (CAR) — statewide REALTOR® association
- Denver Metro Association of REALTORS® (DMAR) — Denver, Aurora, Lakewood, Arvada, Centennial, and the Front Range metro (largest in Colorado)
- Pikes Peak Association of REALTORS® — Colorado Springs, El Paso County
- Boulder Area REALTOR® Association — Boulder, Longmont
- Fort Collins Board of REALTORS® — Fort Collins, Loveland, Larimer County
- Grand Junction Area REALTOR® Association — Grand Junction, Mesa County (Western Slope)
- Pueblo Association of REALTORS® — Pueblo, Pueblo County
Statewide partner contractor coverage available for properties outside the 14 directly-served cities.
Realtor FAQ
Colorado Real Estate Radon Questions Realtors Ask
Frequently Asked Questions
Does Colorado law require radon testing before a home sale?
Colorado does not legally require pre-sale radon testing, BUT Colorado law requires sellers to disclose any KNOWN radon test results to buyers. Colorado SB 23-206 governs residential radon disclosure on sale. In practice, most Colorado real estate transactions now include a radon contingency clause in the purchase agreement, and the Colorado Association of REALTORS (CAR) recommends testing as standard practice. Many lenders — particularly FHA-backed loans — increasingly require radon testing as a condition of loan approval in high-radon zones.
What is the standard radon testing protocol for Colorado real estate transactions?
For real estate transactions, EPA recommends a short-term test (48-96 hours) using either a charcoal canister or continuous radon monitor (CRM) under closed-house conditions. The CRM method is preferred for transactions because it provides hour-by-hour readings that can detect tampering (windows opened during the test) and supplies a defensible time-stamped result for closing documentation. Colorado Radon Experts partner contractors use AARST-NRPP-certified Femto-TECH and Sun Nuclear CRMs for all transaction testing.
If a radon test comes back elevated, can mitigation be completed before closing?
Yes. Standard Colorado real estate transaction radon mitigation timeline: Day 0 — test result received (elevated, >4 pCi/L); Day 1-3 — partner contractor on-site assessment; Day 3-5 — written quote provided; Day 5-7 — buyer/seller agreement on cost responsibility; Day 7-10 — mitigation system installed (typically 4-8 hours of on-site work); Day 11-14 — post-mitigation verification test conducted; Day 14 — final report ready for closing documentation. The full cycle typically takes 7-14 days, fitting within most Colorado real estate transaction inspection contingency windows.
Who typically pays for radon mitigation in a Colorado real estate transaction?
Colorado Association of Realtors data suggests roughly 60% of radon mitigations in Colorado transactions are seller-paid, 30% are negotiated cost-share or credit-at-closing arrangements, and 10% are buyer-paid. The Colorado Real Estate Purchase Agreement does not mandate which party pays — this is negotiated between buyer and seller after an elevated test result. Many Colorado listing agents now recommend pre-listing radon testing so sellers can either mitigate proactively or price-adjust before listing, avoiding mid-transaction disputes.
Are FHA loans different on radon requirements in Colorado?
HUD Handbook 4000.1 does not require radon testing for FHA-backed loans as of 2026, but HUD strongly encourages radon testing on all FHA-insured properties. Some FHA underwriters in high-radon states (Colorado is among the highest-radon states) request radon test results during underwriting, and many Colorado FHA lenders include radon testing as part of standard inspection requirements. USDA Rural Development loans similarly encourage testing. VA loans do not require radon testing but VA appraisers may flag elevated radon as a property condition issue. New construction homes with builder warranties commonly include radon-resistant construction (RRNC) per Colorado builder code recommendations.
Can radon testing be done at the same time as a home inspection?
Yes, and this is the standard Colorado practice. Most Colorado home inspectors place a continuous radon monitor (CRM) during the inspection and retrieve it 48-96 hours later when they return for the final inspection report walkthrough. Some inspectors are certified to provide radon testing themselves; others coordinate with partner radon companies like the Colorado Radon Experts network. Coordinating testing with inspection compresses the transaction timeline.
Does an existing radon mitigation system need to be tested before transfer of ownership?
Best practice — yes. Colorado Association of Realtors recommends post-mitigation verification testing whenever a home with an existing radon system changes ownership. This confirms the system is functional and currently maintaining indoor radon below the EPA action level of 4 pCi/L. Many Colorado real estate transactions include verification testing of existing systems as a buyer-protection step. If the seller cannot produce documentation of the original mitigation install plus regular biannual testing, buyers commonly request a current verification test as a condition of closing.
Colorado MLS — how should radon mitigation be disclosed in listing notes?
Colorado MLS listings should disclose: (1) Whether radon testing has been performed and the date + result, (2) Whether a radon mitigation system is installed and the installation date, (3) Date of the most recent post-mitigation verification test and the result. The the Denver Metro Association of REALTORS (DMAR) and the Colorado Association of REALTORS (CAR) have provided guidance encouraging full radon disclosure on all Colorado MLS listings. Sellers who have proactively tested and mitigated typically command faster offers and higher closing prices because radon uncertainty is removed from buyer negotiations.
How does Colorado Radon Experts work with real estate agents?
Colorado Radon Experts is a lead-routing service that connects realtors and their clients with NRPP-certified, Colorado DORA-licensed partner contractors statewide. Realtors can request testing or mitigation services directly through our contact form or by calling our routing line. Standard turnaround: response within 4 business hours, on-site visit within 2-7 days, post-mitigation verification testing included. We do not pay referral fees — Colorado law prohibits paying real estate licensees for unlicensed work referrals. We do provide expedited closing-timeline scheduling at no premium for licensed Colorado realtors.
Colorado Realtor? Set Up a Direct Partnership Line.
Realtors get expedited routing, transaction-grade documentation, and direct partner contractor access for every Colorado listing. Call (720) 605-9116 or submit a quote request.