Free Radon Test Colorado: What Homeowners Need to Know
The Colorado Department of Public Health and Environment runs one of the more accessible state radon-kit programs in the country. Eligible Colorado residents can request a free mail-in radon test kit while supplies last, and several county and city health departments along the Front Range run periodic free-kit campaigns that supplement the state program. This guide summarizes EPA and CDPHE guidance current as of 2026, walks through how to request a free Colorado kit, explains what the kit measures, and describes what to do with the result. Radon does not cause acute symptoms; the public-health rationale for testing is to identify and reduce long-term lung cancer risk, which EPA and the Surgeon General estimate causes approximately 21,000 deaths per year in the United States. Consult your physician for any respiratory symptom concern.
The CDPHE Free Radon Test Kit Program
CDPHE’s Radon Program offers a citizen mail-in test kit at no cost to Colorado residents. The program is funded through a combination of EPA State Indoor Radon Grant funds and Colorado general-fund appropriations. Availability is “while supplies last” — kits are distributed in batches, and the program periodically pauses when stock is depleted and resumes after the next purchase order. Homeowners can check current availability through the CDPHE radon program website or by calling the program directly.
The free kit is typically a short-term charcoal canister or alpha-track detector, supplied by an accredited laboratory under contract with CDPHE. The kit arrives in the mail with closed-house instructions, a detector with an exposure card, and a postage-paid return envelope. The homeowner deploys the detector in the lowest livable level for the duration specified in the instructions (typically 2 to 7 days for short-term charcoal, 90 days or longer for alpha-track), then mails it back. The laboratory analyzes the detector and reports the result by mail, email, or both. Turnaround is typically two to four weeks from mailing the detector back.
Eligibility for the Free Kit
The free CDPHE kit is available to Colorado residents who have not previously received a free kit for the same property within the program’s standard interval. Some county and city programs layer additional eligibility — income-qualified households, homes built before a certain year, or properties in specific high-risk zip codes. The CDPHE program website lists current eligibility requirements and any documentation needed at the request stage. Most Colorado homeowners qualify for at least one free kit per property over the life of the program.
County and Local Programs That Supplement CDPHE
Several Front Range counties run their own free-kit campaigns in addition to or in coordination with CDPHE. Boulder County Public Health periodically distributes free kits at health-fair events and through local libraries. El Paso County runs occasional free-kit drives, particularly in January (which is National Radon Action Month). Jefferson County Public Health has distributed kits through community outreach events. Larimer County and Weld County operate similar programs. Adams County and Denver Public Health partner with CDPHE on broader Front Range coverage. A homeowner should check both the state program and the local county health department to maximize the chance of receiving a kit during any current distribution window.
City-level programs occasionally appear too. Some Front Range municipalities partner with local libraries to circulate test kits the way a library circulates books — a homeowner checks out the kit, deploys it for the required duration, returns it to the library, and the library mails the detector to the lab on behalf of the patron. These programs are limited but appear in cities including Boulder, Fort Collins, and Longmont.
How to Request a Free Colorado Kit
The standard request pathway has three steps. First, visit the CDPHE Radon Program website and locate the kit-request page. Second, complete the request form with the property address, mailing address (if different), and any required eligibility information. Third, submit the request and wait for the kit to arrive by mail. Typical delivery time is two to four weeks during active distribution periods and longer when supplies are depleted.
If the CDPHE site indicates supplies are exhausted, the next pathway is to check the county health department’s website for any local distribution. If neither is currently distributing, a paid alternative through a certified provider runs $25 to $75 for a charcoal kit and $125 to $250 for a continuous-monitor test by a certified provider. The local radon testing guide walks through the paid options and vetting framework.
Deploying the Free Kit Correctly
The result of the free kit is only as good as the deployment that produced it. EPA-protocol closed-house conditions must be maintained for at least 12 hours before the detector is set out and for the entire duration of the test. Closed-house means doors and windows kept closed except for normal entry and exit, exhaust fans used only briefly, no whole-house fans operating, and no air conditioner cycling that exchanges outdoor air. The detector itself must be placed in the lowest livable level — the basement family room or the lowest occupied bedroom is typical — and positioned away from drafts, exterior walls, sources of heat, and direct sunlight. The kit instructions describe these placement rules in detail, and a homeowner who deviates from them is reading a non-protocol result that may not reflect typical indoor conditions.
Common deployment mistakes include placing the detector on top of an air register, near a frequently opened window, in a remote unoccupied utility room, or for less than the minimum exposure period printed on the card. Each of these mistakes produces a result that systematically biases low and understates the actual occupant exposure. The closed-house and placement rules exist for a reason — they convert a charcoal canister into a meaningful measurement of indoor air quality.
What the Free Kit Actually Measures
The free kit measures indoor radon concentration in picocuries per liter (pCi/L). A 2 to 7 day charcoal canister measures the average concentration over the deployment period. A 90-day alpha-track detector measures the average over a longer period and produces a more representative estimate of annual indoor concentration. Both methods produce a single number — the time-averaged concentration during the deployment.
EPA recommends mitigation when the indoor concentration reaches or exceeds 4.0 pCi/L. EPA also recommends consideration of mitigation between 2.0 and 4.0 pCi/L because there is no known safe level — the risk is dose-dependent across the entire range. Colorado’s statewide median indoor concentration is approximately 4 pCi/L, roughly twice the U.S. average. Many free-kit results in Colorado return values above 4 pCi/L on the first measurement.
What to Do With the Result
The result determines the next action. A result below 2.0 pCi/L is reassuring; EPA recommends retesting every two years to confirm sustained low concentration. A result between 2.0 and 4.0 pCi/L falls in EPA’s consideration range; the next step is typically a confirmation test — either a longer-duration alpha-track or a second short-term test — to verify the result. A result at or above 4.0 pCi/L meets the EPA action level; the next step is mitigation.
Mitigation is the engineered installation of a sub-slab depressurization system or comparable technology that draws soil gas from beneath the foundation and exhausts it above the roofline. Standard residential mitigation runs $1,500 to $3,500 in Front Range markets. CDPHE maintains a list of certified mitigators, separate from the measurement-professional list, and homeowners should use the state list to vet mitigation contractors.
Reading the Mailed Result Report
The laboratory report includes the property address, the deployment dates, the detector identification, the analytical result in pCi/L, and a brief interpretation. Some reports include a comparison to the EPA action level and a recommendation for the next step. A homeowner should keep the report with their property records — the result becomes part of the home’s environmental history, and future buyers’ inspectors may ask about prior testing during real-estate due diligence. A clean documented history of testing supports the future disclosure obligation regardless of whether the result was above or below the action level.
Limitations of the Free Kit
The free kit is appropriate for informational testing — it tells the homeowner whether radon is a concern in the property. It is not always the right tool for real-estate transactions, which generally require a continuous-monitor test by a certified provider with documented chain of custody. A free kit deployed by an unwitnessed seller during a buyer’s contingency period can be challenged because the deployment is not observed by an independent party.
The free kit also produces a single time-averaged number without the hourly fluctuation data that a continuous-radon-monitor provides. The fluctuation data can be useful for diagnosing entry pathways and verifying closed-house compliance. For most informational purposes, the time-averaged number is sufficient. For diagnostic purposes during mitigation system design, a CRM is typically preferred.
What Happens If You Cannot Find a Free Kit Right Now
If the CDPHE program is between distributions, the practical alternatives are paid testing through a certified provider or a paid kit through a hardware retailer or online seller. Charcoal kits sold at hardware stores typically run $20 to $40 plus the laboratory analysis fee (sometimes included in the kit price, sometimes billed separately). Mail-order kits from online radon-testing services run similarly. A homeowner facing a real-estate timeline or a recent renovation that warrants prompt testing should not wait for the next free-kit distribution — paid testing is inexpensive enough that delay is rarely justified.
National Radon Action Month
January is National Radon Action Month, designated by EPA in coordination with state radon programs. CDPHE and several Front Range county health departments concentrate their free-kit distribution during January and the surrounding winter months for two reasons. The first is awareness: the public-information push aligns with the national campaign. The second is measurement timing: winter is the time of year when indoor radon concentrations are typically highest because of the stack effect, so a January test captures conservative (worst-case) indoor exposure. Homeowners who want a meaningful baseline often deploy their free kit during the heating season for exactly this reason.
Why Colorado Pays for Free Kits
Colorado funds the program because the public-health math is favorable. The state is EPA Zone 1 across most of its area, statewide median indoor radon is approximately twice the U.S. average, and lung cancer is a substantial cause of mortality. Reducing indoor radon through testing and subsequent mitigation has a measurable population-level benefit, and the cost of free-kit distribution is small relative to the lung-cancer treatment costs avoided. The program is an example of preventive public-health investment with a long-payback structure.
The radon testing pillar guide covers the broader testing framework, and the house-characteristic indicators guide describes which Colorado homes have the strongest reason to test first.
References
- CDPHE Colorado Radon Program — Colorado Department of Public Health and Environment
- EPA radon program — Environmental Protection Agency
- American Lung Association radon resources — Lung.org
- EPA Citizen’s Guide to Radon — Environmental Protection Agency
Front Range homeowners who have completed a free CDPHE test and need help with follow-up steps can reach our team through the contact page for a referral to a certified mitigator.