Radon is a colorless, odorless, invisible gas that can only be detected through radon testing. It is produced by the natural decay of uranium found in nearly all soils across the United States. Due to the natural geology of Southwest Colorado, the percentage of homes in this area with unsafe levels of radon is higher than the national average. Radon gas can seep in through cracks in foundations, crawl spaces, or well water. Testing your home is easy and, if necessary, fixing the problem is much easier and cheaper than other home repairs.

Radon exposure is the nation’s second-leading cause of lung cancer and the leading cause in people who have never smoked. The Environmental Protection Agency estimates that exposure to radon in the home is responsible for over 500 deaths annually in the state of Colorado. SJBPH and CSU Extension encourage local residents to take action by learning how to use a free radon test kit and how to understand your results so you can keep your family safe.

SJBPH holds free online radon testing workshops in January and February, for Archuleta, La Plata, and San Juan County residents. Radon test kits for first-time testing are made available for pick-up after these workshops, along with training on how to properly set up a test and how to interpret your results. To maximize test accuracy, SJBPH does not distribute radon tests without also training you how to use them properly. In general, SJBPH does not recommend first-time testing in the spring and summer, but follow-up testing may be done at any time.

If you attended a workshop in early 2022 and still need a test, please call 970-335-2097 to make an appointment. Long-term test kits are available for follow-up testing year-round. To obtain a follow-up test kit, call 970-335-2097. For more information on radon risks, testing and mitigation, click through the tabs below.



Radon Project Coordinator | 970.335.2097


The first step to understanding your radon exposure is to perform a short-term radon screening test. Test kits are placed in the home for three to seven days and then mailed to a laboratory using a self-addressed, stamped envelope. Test kits should be hung in the air in the center of a room on the lowest living level of a home (including a finished basement if it is regularly used).

Test kits are available for free from SJBPH at our workshops. By attending a 30-45 minute workshop, you can understand how to properly place, deploy, take down, and mail the test kit.

The winter is the ideal time to test for radon, because it’s hard for radon to rise through layers of snow or frozen ground, which means it may find an easier path through cracks in your foundation or through your crawlspace or well water. SJBPH recommends that all first-time radon testing be done in the winter months. Subject to funding availability, SJBPH will again offer radon workshops in winter 2022-23.

As of July 1, 2022, all radon testing in Colorado must be done by a licensed radon professional, except for homeowners testing a home that they own and occupy.

Reminders: time your three-to-seven-day short-term radon test such that the test is complete by Monday morning. Then take your kit to the post office, after removing the hanging hook. Make sure the kit is at your post office prior to mail going out on Monday. If you miss this deadline, the kit may not arrive at the laboratory before it expires on Thursday. Write down your test kit serial number before you mail it so you can look up the results.

Interpreting your results:

Your short-term radon test results will be available from this link within a few days of testing. Radon is measured in picocuries per liter (pCi/L). The EPA has set a standard of 4 pCi/L in homes, but this standard is not a requirement your home must meet. Instead, it reflects a level that you can expect to achieve with proper mitigation. If your result is less than 4, file your results away and re-test in four to five years. If your result is between 4 and 8, SJBPH and CSU Extension recommend following up with a long-term radon test taking three to twelve months. Contact SJBPH directly at 970.335.2060 (La Plata or San Juan Counties) or 970.264.2409, ext 3008 (Archuleta County) to obtain a long-term test kit. If your result is above 8 pCi/L, we recommend verifying this result with an additional short-term test before proceeding.

If you have a long-term radon level of over 4 picocuries per liter (pCi/L), SJBPH recommends considering a mitigation system. Mitigation is slightly different in every home, but in general, it involves redirecting airflow from the soil underneath your home into a vent pipe that reaches above your roof. This means the radon gas never enters your living space and is vented harmlessly into the atmosphere.

Finding a mitigation contractor:

As of July 1, 2022, all radon mitigation in Colorado must be done by a licensed radon professional, except for homeowners installing mitigation in a home that they own and occupy. We recommend using a mitigation contractor certified by either the National Radon Proficiency Program or the National Radon Safety Board, even in owner-occupied homes. Radon mitigation systems tend to be much cheaper than other major home repairs or appliance replacements and can literally save your life.

For questions about mitigation, contact SJBPH directly at 970-335-2097.

Radon is a radioactive gas (element number 86) produced by the natural radioactive decay of uranium that is present in Southwest Colorado’s soils. Radon particles can be directly inhaled, or can decay further into polonium, bismuth, and radioactive forms of lead, any of which can enter your lungs by attaching to dust particles. Whatever the form, these radioactive products emit deadly alpha and beta radiation within the lung, which can cause lung cancer.

There is no purely “safe” level of alpha or beta radiation, but the risk is higher if radiation levels are higher or if the period of exposure is longer. In other words, living in a home with 4 pCi/L of radon for one year has a certain level of risk, but the risk of cancer is higher if that home’s radon level is 8 pCi/L, or if you live in the home for two years. Of course, no level of radon is a guarantee that you will have health problems, but higher levels do mean more risk.

Radon is a more serious health risk in smokers. The risk of radon-induced lung cancer is estimated to be about ten to fifteen times higher for people who smoke compared to those who have never smoked. Visit Colorado QuitLine for assistance quitting tobacco.

Citizen’s Guide to Radon

The guide to protecting yourself and your family from radon.

Manual Informativo Sobre El Radón

La guía para proteger a su familia y a usted del radón.

Radon and Real Estate Transactions

Discovering elevated radon levels doesn’t mean you need to walk away from the deal!