Radon Testing in Utah: What Every Home Buyer Needs to Know
March 2026 · 6 min read · By Beau Brown, InterNACHI Certified Inspector
Utah has some of the highest radon levels in the country — and most buyers don't know it until after they've closed. Here's what you need to know before you buy.
Why Utah Has a Radon Problem
Radon is a naturally occurring radioactive gas that forms from the decay of uranium in soil and rock. It seeps up through the ground and into buildings through cracks in foundations, gaps around pipes, and other openings. Once inside, it can accumulate to dangerous levels — and you cannot see it, smell it, or taste it.
Utah sits on some of the most uranium-rich geology in the United States. The state played a significant role in the Manhattan Project during World War II, with uranium mining operations throughout the Colorado Plateau and the Wasatch Range. That uranium-bearing geology is still here, and it is still producing radon.
The EPA classifies radon risk by county. Salt Lake County, Utah County, Weber County, Davis County, and Summit County are all classified as Zone 1 — the highest risk category, with predicted average indoor radon levels above 4 pCi/L. That is the EPA's action level, the point at which mitigation is recommended.
The Health Risk
Radon is the second leading cause of lung cancer in the United States, responsible for approximately 21,000 deaths per year according to the EPA. The risk is cumulative — it builds up over years of exposure. Non-smokers who live in high-radon homes have a significantly elevated lung cancer risk. Smokers in high-radon homes have an extremely elevated risk.
The good news is that radon is fixable. A radon mitigation system — typically a sub-slab depressurization system installed by a licensed contractor — can reduce indoor radon levels by up to 99%. These systems cost between $800 and $2,500 to install and require minimal maintenance.
How Radon Testing Works
C&H Inspections uses continuous electronic radon monitors for all testing. These devices are placed in the lowest livable area of the home — typically the basement or first floor — and run for a minimum of 48 hours. They record radon levels every hour, producing a detailed report that shows average levels and any fluctuations.
Continuous monitors are more accurate and tamper-resistant than the charcoal canister tests that were common in the past. They also provide a time-series record that can detect if conditions changed during the test period.
What the Numbers Mean
Radon is measured in picocuries per liter (pCi/L). The EPA action level is 4.0 pCi/L — at or above this level, mitigation is recommended. The EPA also suggests considering mitigation at levels between 2.0 and 4.0 pCi/L. The average indoor radon level in the United States is 1.3 pCi/L. The average outdoor level is 0.4 pCi/L.
In Utah, it is not uncommon to find homes with radon levels of 8, 10, or even 20 pCi/L. We have tested homes in the Salt Lake Valley with levels above 30 pCi/L. These are not rare outliers — they are a predictable result of Utah's geology.
What to Do If Radon Levels Are High
If your radon test comes back at or above 4.0 pCi/L, you have several options. You can negotiate with the seller to have a mitigation system installed before closing. You can request a price reduction to cover the cost of installation. Or you can install the system yourself after closing.
Radon mitigation is a routine and well-understood process in Utah. Most licensed contractors can complete an installation in a single day. The system typically consists of a pipe inserted through the slab or into the crawl space, connected to a fan that draws radon-laden air out from under the home and exhausts it above the roofline.
Should You Test Every Home?
Yes. There is no reliable way to predict radon levels based on location, age of home, or construction type. We have tested brand-new homes with high radon levels and older homes with low levels. The only way to know is to test.
C&H Inspections offers radon testing as an add-on to any home inspection for $150. We place the monitor at the start of the inspection and retrieve it 48 hours later. You receive the results digitally as part of your inspection report.