Radon Testing in El Paso County, Colorado
El Paso County sits squarely in EPA Radon Zone 1, the agency’s highest-risk category, where the predicted average indoor radon level meets or exceeds the 4 pCi/L action threshold, and its Pikes Peak granite geology gives radon a strong natural source. Centered on Colorado Springs at roughly 6,000 to 7,000 feet of elevation, the county’s homes, from historic downtown and Old Colorado City to sprawling newer suburbs and military-adjacent housing, offer radon plenty of entry points through slab cracks and foundation openings. Radon is a colorless, odorless radioactive gas and the second-leading cause of lung cancer after smoking. This county hub explains how radon testing works here, why the local picture demands it, and which city pages to read next. This summary reflects EPA and CDPHE guidance current as of 2026; consult a certified professional for testing decisions.
Radon testing in El Paso County: what to know
Radon testing measures the gas accumulated inside a home in picocuries per liter, and the EPA recommends action at or above 4 pCi/L. Because the entire county is Zone 1, a meaningful share of El Paso County homes test at or above that line, and two neighboring houses can read very differently depending on foundation cracks, soil contact, and how hard the heating system pulls air. The only way to know a specific home’s level is to test it. For the underlying science and device types, our plain-language radon guide for Front Range homeowners covers both short- and long-term approaches.
Short-term tests of 2 to 7 days suit real-estate timelines, while long-term tests of 90 days or more average seasonal swings for a fuller exposure picture. The device belongs in the lowest livable level, a finished basement in a Colorado Springs home, a ground-floor room in a slab-on-grade Fountain build, under closed-house conditions, set about 20 inches or more above the floor and away from drafts and drains.
A point that catches many El Paso County buyers off guard is how much readings vary between similar homes. Two houses on the same Falcon street, built by one builder in the same year, can return very different radon numbers because the granite-bearing soil beneath each foundation varies, because one has a slab crack the other lacks, and because their furnaces and winter sealing draw soil gas inward to different degrees. A neighbor’s clean test, or the seller’s old result, therefore tells you little about the specific home under contract. Radon is a per-home measurement, and over the county’s granite geology that variability is precisely why each individual property has to be tested rather than assumed safe by association.
Why El Paso County homes need radon testing
Geology is the driver, and El Paso County’s is notable. Radon comes from the natural decay of uranium in soil and rock, and the granite of the Pikes Peak batholith underlying much of the county is a strong radon source, which is part of why the EPA maps the whole county as Zone 1. The high elevation and the dry, granitic soils give soil gas ready pathways into homes through slab cracks, control joints, and foundation penetrations.
Climate concentrates what the geology supplies. Winters are cold enough to keep homes sealed for months, and furnaces create slight negative pressure that pulls soil gas indoors, so indoor radon typically peaks in winter. The dry climate means many homes rely on evaporative coolers and tight winter sealing, both of which limit air exchange and let radon accumulate once it enters. Even the county’s newer, energy-efficient suburban and military-adjacent homes trap radon effectively because outdoor air exchange is low.
The lived-in lower level is what makes radon a genuine occupancy concern here. A finished basement office in a Colorado Springs home or a ground-floor bedroom in a Fountain slab house is both the lowest, most soil-contacted space and a place where people spend hours daily. That pairing of maximum soil contact and maximum time is the worst case for exposure, which is exactly why testing the lowest livable level matters across this county.
What an El Paso County radon test covers
A professional test places a calibrated continuous radon monitor or a passive device in the lowest livable level under closed-house conditions, and the tester documents placement and the closed-house window so the result holds up if it feeds a real-estate negotiation.
Closed-house conditions
For at least 12 hours before and during a short-term test, windows and exterior doors stay closed except for normal entry, which keeps a dry, breezy Colorado Springs day from artificially lowering the reading. If a test comes back at or above 4 pCi/L, the next step is mitigation, detailed in our guide to radon mitigation in Colorado Springs.
Continuous monitors versus passive kits
A continuous radon monitor logs hourly readings, so it can show whether a window was opened mid-test, evidence that protects a buyer from a tampered result, which makes it the preferred tool for an El Paso County home sale. Passive charcoal or alpha-track kits average exposure at lower cost and suit a homeowner’s own long-term picture over a full heating season.
Radon testing by El Paso County community
Housing and terrain change where radon collects across the county. In Colorado Springs, the mix of finished-basement homes downtown and slab-on-grade builds in newer areas means the test goes in the lowest livable level, whether that is a basement office or a ground-floor room. Manitou Springs and the foothill neighborhoods, set on granitic terrain, often pair partial basements with strong soil-gas pathways, so placement and closed-house discipline matter.
In Fountain and Security-Widefield, slab-on-grade homes still warrant ground-floor testing because radon enters through slab cracks and joints, while Monument and Black Forest, at higher elevation over granite with crawlspaces and full basements, frequently return elevated readings. Falcon and the eastern plains subdivisions, tightly built and newer, trap radon efficiently once it enters. Military-adjacent housing near Fort Carson, Peterson, and Schriever shares the same Zone 1 exposure. The constant across every community is the granite-driven Zone 1 status, which makes the test non-negotiable wherever the home sits.
Radon testing cost in El Paso County
A professional short-term radon test in the El Paso County market typically runs about $135 to $250, while a do-it-yourself kit costs roughly $15 to $40 plus lab fees, and CDPHE periodically offers discounted kits to Colorado residents. Bundled into a pre-purchase inspection, radon testing often adds just $100 to $175 rather than a separate trip charge.
Weigh the cost against the protection. The EPA links thousands of lung-cancer deaths a year to radon, and El Paso County’s Zone 1 status combined with its granite geology puts local exposure among the highest in the state. A roughly $200 test that catches a 7 pCi/L finished-basement reading lets a family install a mitigation system, often around $1,200 to $2,000 here, and cut exposure by 90 percent or more. Skipping the test leaves the risk invisible for as long as the family lives there.
For homeowners weighing a kit against a professional test, the decision usually comes down to purpose. A CDPHE discounted long-term kit, left in place over a full heating season, gives a representative annual average for a few dollars plus lab fees and is a reasonable first step for an owner who simply wants to know their number. A professional continuous-monitor test, with hourly logging and tamper detection, is the standard for a real-estate transaction because the result must hold up when it drives a mitigation request or a price negotiation, and it fits the inspection timeline a buyer under contract has to meet. Given the county’s strong granite radon source, neither the high-elevation dry climate nor a low neighbor’s reading is a reason to skip the test; the only way to know a specific El Paso County home’s level is to measure it.
Colorado regulations and disclosure
Colorado requires radon disclosure in residential real-estate transactions, and the Seller’s Property Disclosure asks sellers to report known radon results and any existing mitigation system. CDPHE runs the state radon program, references the 4 pCi/L EPA action level, and offers discounted kits to residents. Colorado does not license home inspectors, so for any test tied to a sale, confirm the tester follows recognized national measurement protocols. Buyers in Zone 1 El Paso County should not waive radon testing to sweeten an offer, especially given the granite geology.
Communities and areas served
This hub links the city-level radon pages across El Paso County. The county seat and population center, Colorado Springs, anchors a network including Fountain, Monument, Manitou Springs, Falcon, Security-Widefield, and Black Forest, all within the same Zone 1 footprint where elevated readings are common regardless of town. For city-specific detail, see our pages on radon testing in Colorado Springs and our companion radon mitigation in El Paso County guide.
Because the Zone 1 designation and the granite geology extend across the county, a historic downtown home and a newer Falcon build face the same soil-gas risk; treating radon as a default test rather than an optional add-on reflects the reality of the whole county.
How to choose an El Paso County radon testing provider
Ask whether the provider uses a calibrated continuous radon monitor and follows EPA or AARST protocols, and confirm the calibration is current. A good tester documents closed-house conditions, device placement, and duration so the result stands up in a sale, and for a purchase, places and retrieves the device themselves rather than handing you a kit.
If a result comes back borderline, between 2 and 4 pCi/L, a competent provider explains the options, including a follow-up long-term test, rather than pushing an unnecessary mitigation sale. For homeowners not in a transaction, a CDPHE discounted long-term kit is a low-cost way to get a representative annual average and a reasonable first step before bringing in a professional. Either path beats not testing at all, since every home in the county sits in Zone 1 over granite geology.
Knowing when to test and re-test matters, because radon is not a one-time concern. A home should be tested before purchase, after any major foundation, basement, or HVAC change, and roughly every couple of years even with no changes, since soil conditions and a settling foundation shift the number over time. The granite geology that gives El Paso County its strong radon source does not weaken, so a clean reading years ago does not certify the home today. Winter readings tend to run highest because the home stays sealed against the cold and the furnace pulls soil gas inward, so a short-term test taken in the heating season under closed-house conditions gives the most conservative, decision-grade result for a household here.
References
- Radon risk and EPA zone maps — U.S. Environmental Protection Agency
- Colorado radon program and kits — Colorado Department of Public Health and Environment
- Radon and lung cancer — Centers for Disease Control and Prevention
Every El Paso County home sits in EPA Zone 1 over granite geology, so radon testing is basic due diligence, not optional. To connect with a vetted local tester before your purchase deadline or this heating season, get in touch through our contact page.