If you're buying a home in Denver, you've probably wondered whether a radon test is required before closing. The short answer is no, but the full answer is more useful.

Radon is a colorless, odorless gas that seeps up from the soil beneath your home. This invisible gas is also the second leading cause of lung cancer in the United States. So the real question isn't whether radon testing matters; it's when to test.

You just got your radon test results. Now you're wondering what that number means. Here’s your handy guide to understanding the results.