By David Parks · eXp Realty · The Apollo Group · 2 min read
Radon is a naturally occurring radioactive gas that can build up in homes, and parts of Colorado have elevated levels. A radon test is inexpensive, and a mitigation system can reduce levels if they are high.
Radon is produced as uranium in soil and rock breaks down. It enters homes through cracks, sump pits, and gaps in the foundation. Long-term exposure to high levels is a leading cause of lung cancer, according to the EPA.
A short-term test usually runs at least 48 hours under closed-house conditions, meaning windows and exterior doors stay shut apart from normal entry. Results are measured in picocuries per liter (pCi/L). The EPA recommends fixing a home at 4 pCi/L or higher and considering action between 2 and 4.
The most common fix is a sub-slab depressurization system. A pipe is placed through the slab or crawl space liner and a fan vents the gas outside the house. Installation is usually done in a day.
Test every home, regardless of neighborhood, since levels vary house to house. If results are high, ask the seller to share mitigation costs or install a system. Retest after any changes.
This article is general information, not legal, tax, financial or inspection advice. Every home and situation is different, so confirm details with a licensed inspector, lender, attorney or tax professional.
David is a Greater Denver real estate advisor with eXp Realty and The Apollo Group (Colorado broker license FA100103211). He has closed more than $55 million in volume, earned eXp Icon status in 2025, and holds a 5.0 rating on Zillow from 27 verified reviews.
Denver market updates, new listings, and local tips — no spam, unsubscribe anytime.
