The Iowa Radon Survey has indicated that Iowa has the largest percentage (or 71.6%) of homes above the US Environmental Protection Agency action level of 4pCi/L. It is also designated by the US EPA as an entirely zone 1 state, which means that at least 50% of the homes are above US EPA's recommended action level.

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Radon Data

The data files below include radon tests conducted in private Iowa residences or during real estate transactions. They include test results conducted in houses with and without mitigation systems which met the criteria for a valid test. County data files show aggregate test data for each county. ZIP code data files show aggregate test data for zip codes, but is not sorted by county. Please refer to the Radon Aggregate Data Field List and Descriptions document for more information about the files. To request other radon data sets for research purposes, please contact Angela Leek, Bureau Chief for the Bureau of Radiological Health at (515) 371-2255.

Reference Materials

General Information and References

K-12 Schools

July 1, 2022, House File 2412 was enacted which requires radon testing and mitigation in public schools. The act is an amendment to Iowa Code 280, Uniform School Requirements, which is administered by the Iowa Department of Education. Each attendance center in a school district must be tested for radon at least once by July 1, 2027, and at least once every 5 years thereafter. Testing must be done by and Iowa certified Radon Measurement Specialist or by school district staff that have completed an approved training program. Testing shall be based on recognized national standards. If testing indicates radon levels above 4 pCi/L the district shall employ an Iowa credentialed Radon Mitigation Specialist to develop a radon mitigation plan to be implemented within 2 years of the first test. All new school construction shall incorporate radon resistant construction techniques (RRNC). See link below to review the bill.

The below links are to the recognized national consensus standards for radon measurement and mitigation for schools published by the American National Standards Institute (ANSI) and the American Association of Radon Scientists & Technologists (AARST), standards.aarst.org:

Other informational links:

Childcare Providers

Per Iowa Administrative Code 441-109(237A) which is administered by the Iowa Department of Human Services (DHS), Child Care Regulatory Program, all licensed child care centers must test for radon within 1 year of opening and retest every 2 years. Centers must mitigate if radon levels are above 4.0 pCi/L (picocuries per liter). Below is a guidance document prepared by the Iowa Department of Health and Department of Human Services.

Health Care Providers

Real Estate

There are currently no rules at the state level requiring testing or mitigation during a real estate transaction. However, per Iowa Code chapters 543B.9 and 543B.18 and Iowa Administrative Code 193E Chapter 14 administered by the Iowa Real Estate Commission, a seller must disclose any known tests for the presence of radon and if yes, provide the date of last report and the result(s).  The seller must also acknowledge that they have provided the buyer with a copy of "Iowa Radon Home-Buyers and Sellers Fact Sheet" prepared by the Iowa Department of Public Health. A copy of the fact sheet  can be downloaded from the links below. The buyer must also acknowledge the receipt of the fact sheet on the disclosure statement.

Additional Real Estate related information:

Radon Resistant New Construction (RRNC)

Currently the only statewide requirements for incorporating radon resistant new construction techniques is for public schools, see above section on K-12 Schools. Requirements for the uses of RRNC techniques for all any other structures is by local ordinance or possibly by lending institutions. See additional information below on local jurisdictions with RRNC requirements.

Some Iowa counties and municipalities have adopted into their building ordinances the requirement for the inclusion of RRNC techniques into new home construction. Typically this is by adoption of all or part of Appendix F or AF, Radon Control Methods, of the International Residential Building Code (IRC). Check with your local building regulatory authority for the specific RRNC requirements for your area.

The below link will take you to the current version of the IRC. You can navigate down the contents list on the left side to Appendix AF, click to open. Older versions of the IRC and be selected via the dropdown box in the upper right of the window.

Other Websites on Radon