Radon testing performed at the time of home purchase declined significantly the past two years in Minnesota, and state officials are sounding the alarm about its importance.

The Minnesota Department of Health found that 39% fewer radon tests were done by home inspectors during real estate sales from 2020 to 2022, likely due to buyers' efforts to submit a more competitive offer in a housing market with more demand than inventory. There were 32,537 real estate tests reported by officials in 2020 and 19,976 in 2022.

"These testings have declined in real estate transactions," said Daniel Tranter, indoor air unit supervisor for the Minnesota Department of Health. "We think it has to do with the hot housing market."

Radon is a colorless, odorless gas that occurs naturally in Minnesota soil and causes lung cancer. Heightened levels are found in about 40% of homes across the state — one of the highest rates in the U.S., Tranter said. About 600 radon-related lung cancer deaths occur in Minnesota each year.

Levels in Minnesota are high due to our soil and the fact that people here keep their homes closed up for much of the year, he said.

Nationally, just one in 15 homes has a radon level above 4 picocuries per liter, the rate above which radon is dangerous, he said.

Many people don't know how harmful it can be or don't think warnings apply to their home, he said, and there's no city, state or federal requirement that home buyers or sellers must test for radon.

"It's up to the buyer to decide," Trantor said.

Trantor said anytime is a good time to test for radon, but the point of the home sale is an especially logical time to do it. Buyers might forget about it later, he said.

Realtor Emily Bradley, who works for Keller Williams Realty Integrity Lakes in Minneapolis, said buyers in 2021 and the first part of 2022 were forgoing not just radon tests, but home inspections generally.

"We did see a lot fewer inspections being performed based on the competitiveness of the market during that time," she said, adding that the pendulum is swinging back toward a more balanced situation now.

Declining an inspection sweetens an offer, she said, because then the seller doesn't have to worry about renegotiating the selling price based on any problems the inspection turns up.

Bradley said radon tests are an add-on to regular inspections, along with sewer line checks and chimney inspections.

Over the past two years, she still encouraged buyers who didn't have an inspection before the sale to do one after they move in, "just so that they knew what was going on" with their home, she said. She also urged them to have radon tests done.

John McGrath, a home inspector with WIN Home Inspection SW Minneapolis, said he also saw fewer home inspections during 2021 and 2022.

A home inspection runs between $400 and $700; a radon test adds about $200 to $250 to that cost and is billed separately, he said.

It's the most common "add-on" service performed, and most Realtors and inspectors recommend one, he said.

"I encourage [radon testing] certainly but I can only do so much because they have a primary relationship with their Realtor," he said.

McGrath said he's considering offering a special price on radon tests this winter because January is Radon Action Month.

In a more typical market, 90% of sellers end up paying for a remediation system if high radon levels are found during the inspection, he said.

Trantor, the state's indoor air unit supervisor, said a radon mitigation system costs between $2,000 and $3,000.

Any home can have elevated radon levels, he said, regardless of age, appearance, location or whether neighbors have high levels. Homeowners should test every five years.

"It's a very prevalent issue," he said.