Colorado's Radon Disclosure Law: What El Paso County Buyers and Sellers Should Know

What Does Colorado's Radon Disclosure Law Actually Require?

Since August 2023, Colorado law has required every seller of residential property to give buyers a bold-faced warning that radon is a Class A human carcinogen, along with details of any prior radon testing, results, and mitigation work. Buyers aren't required to test before closing, but the law strongly encourages it — and if you're in El Paso County, that's worth taking seriously, since local test results have consistently run above the national average.

By Jason Roshek | August 25, 2026

Most people have heard of radon in passing. Fewer people realize Colorado actually put a specific disclosure law on the books requiring sellers to address it directly, in writing, with language the state itself decided how to phrase.

If you're buying or selling in the Colorado Springs area right now, this is one of those requirements that's easy to miss — it doesn't get nearly the attention that closing costs or inspection contingencies do, but it shows up in your paperwork either way.

Where This Law Came From, and What It Says

Colorado Senate Bill 23-206 took effect on August 7, 2023, and it changed the Commission-approved Contract to Buy and Sell and the Seller's Property Disclosure form statewide.

Under the law, sellers have to include a specific warning statement, in bold text, telling buyers:

• Radon is classified as a Class A human carcinogen
• Radon is the leading cause of lung cancer among nonsmokers
• Whether the property has been tested for radon before
• The results of any prior tests, including specific concentration levels
• Details of any radon mitigation system already installed
• A copy of the state's official radon brochure

None of this requires a seller to test their home for radon if they haven't already. But if a test has been done — even years ago — the results have to be disclosed. That's an important detail a lot of sellers miss when they're focused on bigger-ticket items like repairs or staging.

Why This Matters More in El Paso County Than You Might Think

Radon is a naturally occurring gas that seeps up from the ground, and how much of it shows up in a given home depends heavily on geology. Colorado, as a whole, tends to run higher than much of the country because of its geology, and El Paso County specifically has reported radon test results that regularly exceed the national average.

That doesn't mean every home in Colorado Springs, Monument, or Fountain has an elevated radon problem. It means the odds of encountering one here are higher than they'd be in a lot of other parts of the country, which is exactly the kind of thing this disclosure law is designed to surface before you're the one living in the house.

What This Means If You're Selling

If you're getting ready to list a home in El Paso or Teller County, here's where radon disclosure actually shows up in your process:

• Check your paperwork history first. If a previous radon test exists — from a prior sale, a home inspection you had done, or even a DIY test kit — you're required to disclose the results, not just the fact that testing happened.
• You don't have to test just to sell. If you've never tested, you're not required to start now. You do have to provide the bold-faced warning language regardless.
• A known issue doesn't have to kill your sale. If a mitigation system is already installed and working, that's disclosed information, not necessarily a red flag — buyers regularly move forward on homes with a documented, functioning mitigation system in place.

I've walked sellers in Divide and Teller County through disclosure conversations like this one before — it's one of several details worth covering early, alongside the broader selling process specific to Divide and Teller County, so nothing catches you off guard mid-contract.

What This Means If You're Buying

If you're touring homes in Colorado Springs, Woodland Park, or anywhere in between, radon testing is one of those due-diligence steps that's easy to skip when you're focused on the inspection, the appraisal, and your financing timeline.

A few things worth doing:

• Ask directly whether the home has been tested before, even though the seller is required to disclose known results — a direct conversation with your agent can surface context that a form alone doesn't.
• Consider a radon test as part of your inspection period, especially on a property in El Paso County, where results have historically run above the national average. Testing is inexpensive relative to almost anything else in your closing costs, and it's typically a short-term test that fits inside a standard inspection window.
• Don't panic over an elevated result. Radon mitigation systems are a well-established, relatively affordable fix — this is a negotiation point, not usually a deal-breaker.

This is exactly the kind of step that's simple to build into your process once you know it exists, and easy to overlook if nobody mentions it. If you're still getting oriented to how a Colorado purchase unfolds start to finish, I've laid out the full home buying process in Colorado in more detail, and radon disclosure fits into that timeline right around your inspection period.

The Bigger Picture

Every property's radon situation is different, and the disclosure law doesn't tell you whether a specific home has a problem — it just makes sure whatever's already known gets put in writing. Whether you're buying or selling in Colorado Springs, Woodland Park, Monument, or Fountain right now, this is exactly the kind of detail worth walking through with someone who handles this paperwork regularly, not something to leave until the contract's already in front of you.

Frequently Asked Questions

Is radon testing legally required before selling a home in Colorado?

No. Colorado's disclosure law doesn't require sellers to test for radon before selling. It requires sellers to disclose the results of any testing that has already been done, along with a mandated warning statement, regardless of whether testing has occurred.

What exactly does a seller have to disclose about radon in Colorado?

Sellers must provide a bold-faced statutory warning about radon's health risks, state whether the property has been tested, share the results and specific concentration levels of any prior tests, and disclose any radon mitigation system that's been installed, along with a copy of the state's radon brochure.

Are radon levels actually higher in El Paso County than elsewhere?

Test results reported in El Paso County have consistently come in above the national average, which is part of a broader pattern across much of Colorado. It doesn't mean every home has an issue, but it's a reasonable factor to weigh when deciding whether to test during your due diligence period.

Does an elevated radon result mean I should walk away from a purchase?

Not necessarily. Radon mitigation systems are a common, well-established, and relatively affordable solution. An elevated test result is typically a negotiation point with the seller rather than an automatic reason to cancel a contract.

Does this disclosure law apply to rental properties too?

Yes. Colorado's radon disclosure requirements extend to landlords, who must provide similar radon information to tenants before a lease begins, not just to home sellers.

Whether you're buying your first home in Colorado Springs or selling a property in Woodland Park or Teller County, radon disclosure is one more detail that's simple to handle correctly once you know it's part of the process — and easy to get wrong if you don't.

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About Jason Roshek
Jason Roshek is a real estate agent serving Woodland Park, Colorado Springs, and the mountain communities of Teller and El Paso Counties. His mission is simple: help people create real wealth through real estate — with expert guidance, honest communication, and a process that doesn't have to feel overwhelming. Whether you're buying your first rural property or selling to fund your next investment, Jason's team is built to help you make smart, confident decisions. Connect with Jason at jasonroshek.com.