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Indiana Mapping Promotes Interest in Testing for Radon

by Margaret Henderson

The Indiana State Department of Health, Indoor Air Quality Program, provides information about Indiana radon potentials and levels and radon prevention and mitigation.

All counties in Indiana are categorized as either Zone 1 or Zone 2 counties, per the USEPA classification.

  • Zone 1 includes counties with predicted average indoor radon screening levels greater than 4 pCi/L.
  • Zone 2 includes counties with predicted average indoor radon screening levels from 2 to 4 pCi/L.

With such high potential for excessive indoor radon, the Program advises the public that the only way to know if you have a radon problem is to test your home. To encourage testing and mitigation and inform the public about radon potentials and findings in their areas, the Program has provided test radon data through a number of maps in order to report findings in understandable, visual ways.

2013 Data
Data for 2013 testing and mitigation is reported in three maps showing number of homes tested, number of homes with mitigation systems installed and the percent of homes with levels > 4pCi/L, the USEPA recommended action level.

Total Number of Homes Tested in Indiana 2013
The total number of homes tested is 15,744. Data are broken out by county into ranges of homes tested as:
• 1-9
• 10-100
• 101-300
• more than 300

Homes with Mitigation Systems Installed 2013
The total number of mitigation systems installed in 2013 was 4,332. Data are broken out by county into ranges of mitigation systems installed:
• 1-9
• 10-25
• 26-100
• more than 100

Percent of Homes with Greater than 4 pCi/L 2013
Homes with test results exceeding 4pCi/L in 2013 are broken out by county into percentages of those in Zones 1 and 2:
• Zone 1 = 36%
• Zone 2 = 35%

2007-2014 Data
Data for the period 2007-2014 is analyzed and presented in mapping the number of homes tested, the number of homes with results > 4 pCi/L, and the highest radon test results in 2014.

Number of Homes Tested for Radon in Indiana 2007 – 2014 (pre-mitigation)
The number of homes tested for radon 2007-2014 equaled 59,451. (This is pre-mitigation testing with analysis as of June 2015.) Data are reported by county in ranges:
• 10
• 10-50
• 101-299
• more than 300

2007 – 2014 (pre-mitigation) Percent of Homes in Indiana ≥ 4 pCi/L for Radon Gas
Test results in home 2007-2014 that had levels in excess of 4pCi/L are given based on their zones:
• Zone 1 = 36.8%
• Zone 2 = 32.7%

Highest Radon Test Results in Indiana – 2014
A statewide map of counties shows that approximately two-thirds of the state is in Zone 1 and one-third is in Zone 2. The highest levels were reported in 12 counties throughout the state. The highest results were all > 70.0 pCi/L.

Additional breakout of mitigation systems installed 2007-2013 is given in another map.

Total Number of Radon Mitigation Systems Installed 2007 – 2013
The number of mitigation systems installed 2007-2013 equaled 12,421 (analysis as of June 2015.) Data are reported by county in ranges of:
• 1-9
• 10-25
• 26-100
• more than 100

For more information about radon in Indiana, contact:
Indiana Department of Environmental Management
Telephone numbers: