Colorado — 2.9M metro

Radon in Denver,
CO

Colorado's Front Range — including Denver — has elevated radon risk from the Rocky Mountain granite geology. Colorado state data shows 45% of tested homes exceed the EPA action level, with Denver metro counties consistently in the high-risk range.

Risk Level

High Risk

2–8 pCi/L

Typical range (area avg.)

EPA action level: 4 pCi/L

Why Denver Has High Risk Radon

The Denver metro area sits on the western edge of the Great Plains where Rocky Mountain plutonic rocks (granite, gneiss) meet sedimentary formations. This transition zone features uranium-rich bedrock that generates significant radon.

Local Housing and Radon Risk

Denver has a large stock of 1950s–1970s ranch homes in neighborhoods like Wheat Ridge, Arvada, and Aurora. Many have unfinished basements with exposed soil floors or cracked slabs — prime entry points for radon.

Testing Advice for Denver Residents

Colorado's high altitude means lower atmospheric pressure, which can draw more radon from soil into homes. Testing is especially important in basement-heavy properties and older homes. The Colorado Department of Public Health provides testing resources.

How to Test Your Denver Home

Step 1: Choose Your Test Type

For initial screening, a charcoal short-term test kit ($12–$25) placed for 48–96 hours provides a quick result. For the most accurate reading, a long-term alpha-track test ($20–$35) left in place for 90+ days accounts for seasonal variation — especially important in Denver's climate.

Step 2: Place the Test Correctly

Test in your lowest livable level — basement if you have one, otherwise the first floor. Keep the test 20 inches from the floor, away from windows and exterior walls. Close windows and doors 12 hours before and during the test for accurate results.

Step 3: Interpret Your Results

Below 2 pCi/L: low concern, retest every 2 years. 2–4 pCi/L: consider mitigation, retest in 2 years. 4 pCi/L or higher: the EPA recommends mitigation. Above 8 pCi/L: prioritize mitigation promptly.

Step 4: Hire a Certified Mitigator if Needed

If your test result is at or above 4 pCi/L, hire a certified radon mitigator. In Colorado, always verify your contractor's state certification. Sub-slab depressurization — the most effective mitigation method — typically costs $900–$1,700 installed in the Denver area.

Frequently Asked Questions — Radon in Denver

Is radon a real problem in Denver?

Yes. Colorado's Front Range — including Denver — has elevated radon risk from the Rocky Mountain granite geology. Colorado state data shows 45% of tested homes exceed the EPA action level, with Denver metro counties consistently in the high-risk range. The EPA recommends all homes be tested regardless of location — radon levels can vary significantly even between neighboring properties.

How much does radon mitigation cost in this area?

In the Denver area, professional radon mitigation (sub-slab depressurization) typically costs $900–$1,700 installed. This is a one-time cost that reduces radon by 50–99%. The system requires minimal maintenance and a mitigator can typically complete the work in 3–5 hours.

Should I test if I have a new home?

Absolutely. New homes built with radon-resistant features still show elevated levels in testing — construction conditions and local geology vary too much to assume any home is safe. Test within the first year of occupancy, especially if your home has a basement.

Can I test radon myself, or do I need a professional?

DIY testing is reliable and recommended as a first step. Short-term kits ($12–$25) and long-term kits ($20–$35) are accurate when placed and returned correctly. Professional testing is only required for real estate transactions in some states. If your DIY test shows elevated levels, use a certified professional for both confirmation testing and mitigation.