Listed for: Testing
Verified:Iowa state license
Call All Pro Home Inspections at (319) 337-6614No website listed
Locations and reports
Radon in Iowa City, Iowa
EPA puts Johnson County, where Iowa City is, in Zone 1, its highest radon zone, and high results are common there: 41.6% of the 7,321 radon tests reported to CDC (2008 to 2017, laboratory totals) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
41.6%
16.9 pts below IA
- Johnson
- 41.6%
- Iowa
- 58.5%
Johnson, 90th of 99 in IA, 2008 to 2017
Median result
3.2pCi/L
Below action level
- Johnson
- 3.2 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of Johnson's tests, 2008 to 2017
Nearest county
60.4%
Cedar, 22 miles
- Cedar
- 60.4%
- Johnson
- 41.6%
765 tests, 2008 to 2017
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
Johnson, where Iowa City is
Tests reported
7,321
In Johnson
- Johnson
- 7,321
- Cedar
- 765
Reported to CDC before any fix, 2008 to 2017
Read a result for Iowa City
Starts at Johnson County's median, 3.2 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.2 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Johnson County's median reported result, 2008 to 2017.
The data
Iowa City, What is published
What is published for Iowa City
Information:
Every figure for Iowa City is a county's
Radon data is published by county, not by city, so for Iowa City it is Johnson County's: its EPA zone (Zone 1) and the 7,321 tests reported to CDC for 2008 to 2017, laboratory. Only a test tells you about one home.
Iowa City covers 25.6 square miles of land, all of it in Johnson County. About 76,229 people live there, 2,978 to the square mile.
Iowa City, Counties
The county Iowa City lies in
MeasuredJohnson County's EPA zone and the figures CDC publishes for it, 2008 to 2017, laboratory.
Johnson CountyZone 1Highest predicted potential
- 41.6%
- Reported tests at or above 4 pCi/L
- 3.2 pCi/L
- Median reported result
- 7,321 tests
- Tests reported to CDC
- None
- Yearly figures on file
Johnson County ranks 90th of 99 Iowa counties with 30 or more tests for that period, 16.9 points below the 58.5% pooled across Iowa's counties, 5.9 points above the national pool of 35.7%.
Measured from the middle of Iowa City, the nearest counties with a CDC figure for 2008 to 2017, laboratory are Cedar County (22 miles, 60.4% of 765 tests), Washington County (24 miles, 54.9% of 1,186 tests) and Muscatine County (25 miles, 46.5% of 954 tests). Across the 8 nearest, the share at or above 4 pCi/L runs from 39.7% to 60.4%; the farthest of them, Keokuk County, is 40 miles away at 60.3%.
The directory lists 3 businesses with an address in Iowa City, 3 for testing. Iowa's other cities with a page of their own: Des Moines, Ames, Sioux City and Waterloo.
The counties around Iowa City
By distance from the middle of Iowa City; counties with 30 or more tests.
Predicted: EPA Map of Radon Zones, by county. Measured: CDC tracking data, by county, 2008 to 2017, laboratory.
Iowa City, Geology
The ground under Iowa City
PredictedUSGS's geologic map puts all of Iowa City's mapped land in one class: high radon potential. All of it lies in the area the map calls Loess-Covered Drift Plains, to which USGS gives a radon index of 13, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Loess-Covered Drift Plains | Pre-Illinoian and Illinoian glacial deposits, and loess. | High | 13 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Iowa City beside its county and Iowa
All of Iowa City, like all of Johnson County, is rated high. On high-potential ground Iowa City is close to Iowa as a whole: 100% of its land against 98.8%.
The map rates the ground, not the air in any home.
Iowa City, Homes
Homes in Iowa City
Iowa City has 33,855 homes, and many share a building: 40% are in buildings of five or more, 41% are detached houses, against 49% across Johnson County. Half of its homes were built before 1984, close to Johnson County's 1991: 21% date from before 1960 and 30% from 2000 or later. Most occupied homes here are rented: owners live in 46% (Johnson County: 59%). A tenant can run a test; a fix is the landlord's to make.
| Homes | Iowa City | Johnson County | Iowa |
|---|---|---|---|
| Housing units | 33,855 | 67,211 | 1,427,175 |
| Detached houses | 41% | 49% | 72% |
| In buildings of 5 or more | 40% | 30% | 14% |
| Mobile homes | 2% | 4% | 3% |
| Built before 1960 | 21% | 17% | 39% |
| Built since 2000 | 30% | 36% | 21% |
| Middle year built | 1984 | 1991 | 1971 |
| Owner-occupied | 46% | 59% | 72% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.
Local help
Iowa City, Professionals
Radon professionals listed in Iowa City
Businesses whose listed city is Iowa City, from the state registries and listings in the Radon411 directory, with the same business and certification status the directory shows.
Radon professionals listed in Iowa City: 1 of 3
3 listings with Iowa City as the city. See radon testing in Iowa City, or all radon professionals in Iowa.
Iowa City, Local resources
Local resources for Iowa City
Who to ask in Iowa: its radon program, test kits and professionals.
- Iowa HHS Radon ProgramRun by Iowa Department of Health and Human Services, phone (515) 281-4928.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
You can reach the Hotline by calling 1-800-383-5992 to order low-cost radon test kits and find answers to your radon questions.
- Compare kits
- Professionals in Iowa3 listings cover Iowa City.
The program's own words on licensing and disclosure are on the Iowa page.
What it means
Iowa City, Questions
Questions about radon in Iowa City
What radon zone is Iowa City in?
Iowa City takes its zone from Johnson County, which EPA puts in Zone 1, the map's highest class: a predicted county average above 4 pCi/L.
What are radon levels in Iowa City?
High results are ordinary around Iowa City: 41.6% of the 7,321 tests reported from Johnson County for 2008 to 2017 (laboratory totals) were at or above 4 pCi/L, the level at which EPA says to fix a home. The median reported result was 3.2 pCi/L.
Should I test my home in Iowa City?
Yes. Johnson County reported about 3,046 of its 7,321 tests at or above 4 pCi/L. That is below Iowa's pooled 58.5%, and still not a reason to skip it, and ranks Johnson County 90th of the 99 Iowa counties with 30 or more tests. Which homes they were, no map can say. How to test a home.
What ground is Iowa City built on, as far as radon goes?
USGS's geologic map puts all of Iowa City on one named area, "Loess-Covered Drift Plains", rated high for radon potential, radon index 13.
Is radon higher in the counties around Iowa City?
It depends which way you go. 7 of the 8 nearest counties with a figure report a larger share than Johnson County's 41.6% and 1 a smaller one: from Linn County (39.7%, 29 miles off) to Cedar County (60.4%, 22 miles off).
Who tests for or fixes radon in Iowa City?
Iowa City is the address of 3 businesses in Radon411's directory, all listed for testing, none for mitigation. Each entry names the public list it came from. Radon professionals in Iowa City.
The answers use the published figures of Johnson County, the county Iowa City lies in.
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