Radon Testing and Mitigation in Fort Collins, CO
Colorado State University anchors a city where century-old Old Town cottages sit a few miles from subdivisions barely a decade old, and that split matters more for radon than most Fort Collins homeowners realize. Fort Collins is the Larimer County seat, with a 2020 census population of 169,810 and a metro area of roughly 375,000 people. Whatever the age of your house, the ground underneath it is the same: Larimer County is an EPA Radon Zone 1 county, the highest-potential category, where the predicted average indoor screening level runs above 4.0 pCi/L.
NoCo Radon Pros is a free matching service. We do not test homes, we do not install systems, and we do not hold a Colorado radon license. What we do is connect you with an independent, Colorado-licensed radon professional who handles the measurement and any mitigation. You can read more about how we work and how we make money at no cost to you.
Why Fort Collins homes sit in Zone 1
The EPA places all of Larimer County in Radon Zone 1, meaning homes here have the highest potential for elevated indoor radon. Statewide, CDPHE reports that about half of Colorado homes test above the 4.0 pCi/L action level. That is a Colorado figure, not a Fort Collins-specific count, but it tells you the odds are real. The only way to know your own number is a test, and radon does not care whether your house is a Victorian near Old Town or a new build off the Harmony Corridor.
Old Town, Midtown, and new south Fort Collins
Fort Collins housing falls into two broad camps, and each has its own radon story. The historic core, Old Town and the craftsman and Victorian blocks around it, predates any radon-resistant building practice. Campus West near CSU, Midtown along College Avenue, and the mid-century homes of University Acres were also built long before passive systems were standard. These older homes often have basements or crawl spaces that can pull soil gas indoors, which is why radon testing is the right first step regardless of neighborhood.
Newer south Fort Collins and the Harmony Corridor are a different case. Fort Collins is among the Colorado cities that require passive radon-resistant systems in new residential construction through locally adopted code (reported adopted in 2005). A passive rough-in does not guarantee a low level on its own. If a test comes back high, activating that rough-in with a fan is often a straightforward job, and a licensed professional confirms the design and result. Our northern Colorado radon levels guide covers the regional picture in more depth.
How testing works before anything else
Nobody should buy a mitigation system before a test says one is needed. A short-term test, placed in the lowest lived-in level of the house, gives you a first number in a matter of days. If that number lands near or above the action level, a follow-up or a longer test confirms it. In a Zone 1 county like Larimer, a low result is not a foregone conclusion, but it is common enough that a test is worth doing whether you live in University Acres or a Harmony Corridor build. The professional you are matched with can place a test or review results you already have. Radon matters here because it is the second leading cause of lung cancer in the United States after smoking, per CDPHE, which is the practical reason the 4.0 pCi/L action level exists.
What happens after a high test result
A result at or above 4.0 pCi/L is the trigger for action. From there, an independent, Colorado-licensed radon professional designs a system for your home. Most Fort Collins homes get a standard sub-slab depressurization system; most run $1,000 to $2,500, with about $1,500 common. Crawl space and basement situations can vary, and our cost guide walks through the bands. See radon mitigation for how the work itself is done.
If you are buying or selling, radon shows up in the paperwork too. Colorado’s disclosure law (C.R.S. 38-35.7-112) requires a bold-faced radon warning in residential sale contracts and seller disclosure of known radon information. Landlords have their own written duties under C.R.S. 38-12-803. Both are covered in our Colorado radon law guide and the disclosure law guide.
Verify the license, then get matched
Colorado licenses radon measurement and mitigation professionals through DORA. The license belongs to the professional, never to this brand. You can confirm any contractor on the state license lookup before hiring. When you are ready, we will match you with a state-licensed local professional. Browse all locations we serve or start from our full services list.