Radon comes up in almost every Colorado transaction I handle. Here’s the short version so it doesn’t catch you off guard. (Educational, not health or engineering advice — refer to the EPA and Colorado Department of Public Health and Environment for official guidance.)
What it is
Radon is a naturally occurring radioactive gas from the breakdown of uranium in soil and rock. Colorado’s geology means much of the state — including the Denver metro, Jefferson County and the foothills — has elevated radon potential. It enters homes through foundations and accumulates in lower levels.
Why it matters
The EPA identifies radon as a leading cause of lung cancer among non-smokers and recommends action at levels of 4 picocuries per liter (pCi/L) or higher. Many Colorado homes test above that.
Testing during a purchase
A short-term test (typically 48 hours or more) is placed in the lowest livable level during the inspection period. Results come back within days. I recommend testing every home, including new construction.
Mitigation
A mitigation system is usually a sealed pipe from beneath the slab to a fan that vents above the roofline, plus sealing of cracks and sump pits. Installation is typically done in a day, and costs are modest relative to the purchase. Many newer homes are built “radon-ready” with a passive system that can be activated.
Negotiating
A high test result is a common inspection item. Buyers often request that the seller install a system or provide a credit. Sellers who test and mitigate before listing remove the issue entirely.
Existing systems
If a home already has a system, check that the fan is running (there’s usually a manometer showing pressure) and consider re-testing to confirm it’s working.
The bottom line: test, mitigate if needed, move on. It’s one item on the Colorado inspection checklist.