Radon Pros in Colorado

Last updated: March 2026

Colorado is one of the highest-risk states for radon in the United States. According to EPA mapping, most counties along the Front Range corridor — from Fort Collins through Denver to Colorado Springs — are classified as Zone 1, the highest predicted indoor radon potential. The combination of uranium-rich granitic bedrock, high altitude (which reduces atmospheric pressure and increases soil-gas draw), and cold winters that keep homes tightly sealed creates conditions that routinely produce indoor radon levels well above the EPA action level of 4.0 pCi/L. Colorado requires radon mitigators to register with the Colorado Department of Public Health and Environment (CDPHE), though national NRPP or NRSB certification is not state-mandated. In real estate transactions, radon testing is not legally required but is extremely common — most buyers' agents along the Front Range recommend it as standard due diligence. What makes Colorado's radon situation distinct is the geographic concentration of risk: the same mountain geology that defines the state's landscape is the primary driver of elevated indoor radon. Homes in Boulder, Jefferson, and Douglas counties frequently test above 10 pCi/L, and post-mitigation verification testing is considered essential.