Radon Statistics by the State


Radon gas is invisible, odorless, and naturally occurs from the decay of uranium found in the earth’s crust. Having been categorized as a carcinogen since 1988, radon is the #1 cause of lung cancer nonsmokers in the United States. With that said, smokers who are exposed to radon will drastically increase their chance of getting the disease. Radon is produced from soil, well water, indoor air, building materials, and public water, but the leading source is soil, at 69.3%. To make that clear, under and around homes is the largest source, which means that dangerous levels of radon can accumulate throughout the entire inside of the home.

How is radon measured?

Radon is measured in units referred to as picocuries per liter (pCi/L). 1 pCi/L of radon is equal to 2.5 cigarettes a day. According to the Environmental Protection Agency (EPA), 4 pCi/L is the recommended radon action level. The amount of radiation in 4 pCi/L of radon is equal to 100 chest X-rays. Most hospitals only allow for people to have 4 chest X-rays a year. The Environmental Protection Agency (EPA) states that if a house tests at that level or higher, it is strongly recommended that they undergo radon mitigation as soon as possible.

What are the statistics throughout the United States?

Radon levels can vary significantly across a single neighborhood, but there are areas of the country that have a higher expected average indoor radon level. According to the EPA, “nearly 1 in 3 homes checked in seven states had radon levels over the recommended action level for radon exposure of 4 pCi/L.” In all of 2020, experts say that 31 states in the US have radon exposure that is higher than 4 pCi/L. Due to the low uranium in their rocks and their absorbance, Hawaii has the lowest radon levels out of all the states with a level of 0 pCi/L. On the other end of the spectrum, with a radon level of 10.7 pCi/L, Alaska is the highest, and homeowners are told to get a radon test every two years.

List of the 10 states with the highest radon levels in 2020:

1. Alaska – 10.7

2. South Dakota – 9.6

3. Pennsylvania – 8.6

4. Ohio – 7.8

5. Washington – 7.5

6. Kentucky – 7.4

7. Montana – 7.4

8. Idaho – 7.3

9. Colorado – 6.8

10. Iowa – 6.1

List of the radon levels in our service area in 2020:

1. Iowa – 6.1

2. North Dakota – 6

3. Wisconsin – 5.7

4. Minnesota – 4.6

According to the map shown below, zone 1 counties (red) have the highest radon levels at over 4 pCi/L. Zone 2 counties (orange) have average radon levels between 2 and 4 pCi/L. Zone 3 counties (yellow) have the lowest radon levels at less than 2 pCi/L, however, even though the risk is lower in these areas, there may still be homes with higher radon levels than the average.

Radon Statistics by the State - Image 1

For other specific numerical statistics on radon levels in our country in the year 2020, you can visit this website:

What can American Waterworks do for you?

At American Waterworks, we provide free inspections and estimates to have a radon mitigation system installed in your home. We also offer a variety of financing options to make sure the project can fit within your budget. Don’t wait to make your home a healthier and safer environment to live and breathe. Call 1-844-801-9520 or click HERE to request a free no-obligation estimate!


our service area

We serve the following areas

IowaWisconsinMinnesotaNorth Dakota
  • Taylor
Our Locations:

American Waterworks
1307 Valleyhigh Dr NW
Rochester, MN 55901

American Waterworks
4119 14th Ave N
Fargo, ND 58102
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