Radon testing is standard in Colorado, and it surprises buyers from other states every time. Much of Colorado has high radon potential, and plenty of tested homes come back elevated. That doesn't make a house a bad buy. It makes radon one more item to handle calmly in inspection week. Here's how I explain it and how to negotiate it.
The short answer
Radon is a natural radioactive gas from soil and rock. You can't see or smell it, so you test. The EPA's action level is 4.0 picocuries per liter (pCi/L). At or above that, the EPA recommends fixing the home, usually with a mitigation system (a pipe and fan that vents gas from under the house). Readings between 2.0 and 4.0 are worth thinking about. Colorado sellers must disclose known radon information and give buyers radon information.
Step by step
- Bring it up before inspection week. Tell buyers at the consult that radon tests are normal in Colorado.
- Book the test with the inspection. Most inspectors offer a continuous radon monitor as an add-on.
- Know the test rules. Usually at least 48 hours, placed at the lowest livable level, under closed-house conditions (windows shut, doors used only to come and go).
- Tell the listing agent. The seller needs to know the closed-house rules. An open basement window can ruin the test.
- Test even if there's a system. Fans wear out. A system is only as good as its current reading.
- Read the result. Below 2.0: low concern. 2.0 to 4.0: consider mitigation, especially if the basement is living space. 4.0 or higher: plan to mitigate.
- Get a mitigation bid. A licensed mitigation contractor can quote the system. Have the number before you negotiate.
- Negotiate in the objection. Ask the seller to install a system with a post-mitigation test, or ask for a credit or price change. See handling the inspection objection.
- Retest after mitigation. A post-install test confirms it worked.
How to explain it to your client
"Radon is a natural gas from the ground, and it's common in Colorado. You can't see it or smell it, so we test. If the number comes back at 4 or higher, the fix is usually a pipe and fan system that vents it outside. It's a known fix, not a deal-breaker. If the test comes back high, I'll get a bid and we'll ask the seller to install it or credit you."
Watch-outs
- Don't give health advice. Point buyers to the EPA and the state health department for health questions.
- Don't panic buyers. A high reading is a fixable item, not a reason to fear the house.
- Closed-house rules matter. A bad test setup wastes days.
- Mountain homes too. Radon isn't just a Front Range issue. Test mountain homes and crawlspaces.
- Disclosure. Colorado has radon disclosure rules for sellers. Make sure the seller has completed them. Ask your managing broker for the current form.
Further reading
- Radon and the Denver home purchase on kennarealestate.com
- Radon in Colorado mountain homes on coloradomountainhomefinder.com
This is training for real estate agents. It isn't legal or health advice. Check with your managing broker.
Questions
What radon level is too high?
The EPA recommends fixing homes at 4.0 pCi/L or higher, and considering it between 2.0 and 4.0.
How long does a radon test take?
Usually at least 48 hours with a continuous monitor.
Who pays for mitigation?
It's negotiated. The seller may install it, give a credit, or the buyer may pay.
Does a house with a system need a test?
Yes. Test to confirm the system still works.
Where can buyers learn more?
The EPA and the Colorado Department of Public Health and Environment publish radon guidance. See epa.gov/radon.
Brian Lee Burke is the founder of PadLeaders, a Colorado real estate broker licensed since 2003, team leader of The Kenna Group at Keller Williams DTC (formerly Kenna Real Estate Group) and the author of Mastering Real Estate and The Real Estate Playbook. More about Brian.