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Radon Levels in Grundy County, Illinois

EPA puts Grundy County in Zone 1, its highest radon zone. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

Predicted
Zone 1Highest predicted potential
Measured
32.3%of 390 tests reported to CDC (2017) were at or above 4 pCi/L
Your home
Test to knowNo area figure here is a reading of your home.
How to test this homeFind a certified tester

The data

Grundy County, At a glance

Grundy County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

This is a county-level geologic prediction. It is not a measurement of any address, and houses with elevated radon are found in all three zones.

What EPA predicts hereScreening level, geology

EPA predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county as a whole.

USGS geologic potential: High across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Grundy County, 2017

Tests reported
390
At or above 4 pCi/L
32.3%
Median result
2.4 pCi/L
Reported results by concentration band, Grundy County, 2017
Under 2 pCi/L: 39%2 to 4 pCi/L: 29%4 pCi/L and above: 32%

Of 390 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Grundy County, 2017: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L15038.5%
2 to 4 pCi/L11429.2%
4 pCi/L and above12632.3%

CDC publishes this figure only for counties here, so there is no state or national number to compare Grundy County, Illinois with.

What these figures count

Distribution of radon tests reported to CDC, not this house. People testing before a sale, or because they suspect a problem, are over-represented in any reported testing data.

The figures at the top are for 2017: a percentage there is a share of radon tests reported to CDC for Grundy County in 2017, and a percentage in a view below is a share of the tests reported for the year or period it names. It is not a share of homes in Grundy County, and it is not a random sample: it counts only the tests people chose to run and that were reported.

CDC works out the shares and the median over pre-mitigation tests, counting a test not marked as before or after mitigation as one of them (390 for 2017). The median is the middle result of those tests, not of buildings. CDC also reports the number of buildings tested (130), a different count, so the two totals are not interchangeable.

Grundy County's own published CDC figures beside those of the counties that border it, for the same period.

Each figure is that county’s own published CDC figure for 2017, counting radon tests reported to CDC, not homes. Grundy County is this page. Nothing is averaged or combined across counties. The test count beside each county is CDC’s published number of pre-mitigation tests behind its figures. Figures from few tests can swing widely from year to year. Every Illinois county’s own figure is in the Illinois county table.

Measured: CDC tracking data. Figure above: 2017. Measured data period: 2005 to 2017 (every CDC figure on file).

Radon Action Brief

National Radon Action MonthPre-sale

Grundy County's radon brief, in one dated file.

  • Your area's radon record, explained.
  • Your plan to test this week.
  • Fix costs and pros near you.

Save 64%Sale price: $8.99Price after the sale: $25Ends Jan 31Then $25

Get the Grundy County BriefSee a free sample

Area data, not a test of the building.

Local help

Grundy County, Local resources

Radon testing and mitigation in Grundy County

Who tests and fixes radon in Grundy County: listed businesses, Illinois's radon program and test kits.

Listed radon businesses with an address in Grundy County:

Listed radon professionals by town: Seneca, Verona

What Illinois's program says
Phone
(800) 325-1245
Licensing of radon professionals
The Agency also licenses and regulates the individuals who provide radon measurement and mitigation to the public.
Disclosure when a home is sold or rented
Illinois Radon Awareness Act - This is the legislation that requires the seller to provide to the buyer of any interest in residential real property the IEMA-OHS pamphlet entitled "Radon Testing Guidelines for Real Estate Transactions" and the Illinois Disclosure of Information on Radon Hazards.

What it means

Grundy County, Questions

Questions about radon in Grundy County

Common questions

8 questions, answered from the figures above

Are radon levels high in Grundy County?

In 2017, 32.3% of the radon tests reported to CDC for Grundy County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.4 pCi/L. That is a share of reported tests, not of homes. EPA places Grundy County in Zone 1, highest predicted potential, a predicted average indoor screening level greater than 4 pCi/L. Homes with elevated levels occur in all three zones, so the figures describe the area, not your house. Testing is the only way to know the radon level in a specific building.

Radon levels: what a result meansWhat is radon?Radon levels in Illinois

How do I get a radon test in Grundy County?

EPA says you can test your home yourself or hire a qualified radon test company, and that either approach takes only a small amount of time and effort. No radon testing business listed on Radon411 has an address in Grundy County or names it as a service area yet. The Illinois radon program is the place to ask about certified testers and any test kit offer it runs.

Radon testing: how to test a homeRadon test kits comparedFree and low-cost kits by stateRadon Action Month checklistIllinois radon program

Who does radon mitigation in Grundy County?

No listed mitigator names Grundy County as a service area yet; the Illinois directory lists 337 companies. EPA recommends having a qualified contractor fix a home with a radon problem, because lowering high radon levels takes technical knowledge and special skills, and some states require the work to be done by a licensed or certified professional. Your state radon program is the place to check whether Illinois requires one.

Radon mitigation: how it worksRadon mitigation costRadon mitigation systemsMitigators in Illinois

What EPA radon zone is Grundy County in?

EPA places Grundy County, Illinois in Zone 1, which EPA describes as highest predicted potential for the area. A zone is a prediction for the whole county and never determines whether a particular home should be tested. EPA recommends testing every home regardless of zone.

Should I test my home in Grundy County?

Yes. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. How to test a home.

When is the best time of year to test?

EPA says short-term tests stay in the home from 2 to 90 days and that all radon tests should run a minimum of 48 hours; long-term tests stay more than 90 days. EPA's guides do not name a best season: they say radon levels tend to vary from day to day and season to season, so a long-term test is more likely than a short-term test to tell you the year-round average.

What does it cost to test?

EPA's Citizen's Guide calls testing easy and inexpensive, and EPA's Home Buyer's and Seller's Guide says passive short-term and long-term devices are generally inexpensive, while active devices may cost more. No national average price is published for this, so Radon411 does not give one. What testing costs.

Which counties border Grundy County?

Grundy County borders 5 counties, derived from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county's report can be relevant.

If you own, buy, sell or rent

What these figures mean for each reader, with the guide that covers it

The reported-test figures on this page describe Grundy County, Illinois in 2017. They describe tests other people carried out in other buildings, and none of them measures yours.

Grundy County in figures

The figures above, said in words

What the published data says about Grundy County, in words. A zone and a share of tests describe an area, never the level in any one home.

    • Predicted

      Predicted

      EPA places Grundy County in Zone 1, highest predicted potential, as it does 55 other counties of Illinois's 102.

      Of the 5 bordering counties, EPA places Kendall County, LaSalle County and Livingston County in Zone 1 and Kankakee County and Will County in Zone 2.

  • Reported tests

    Measured

    CDC has annual figures for Grundy County for 4 years, 2014 to 2017. In 2017, 32.3% of 390 reported tests were at or above 4 pCi/L.

    Across those years the share ranged from 0.0% (2016) to 50.6% (2015). Few tests in a year can move it a long way.

  • Local record

    Illinois's radon program is the IEMA-OHS Radon Program, run by Illinois Emergency Management Agency and Office of Homeland Security; its contacts are under Local resources.

    The county's largest incorporated places are Morris, Channahon and Minooka; the figures here cover them as part of the county.

Products

Grundy County, Products

Testing and mitigation products

Whatever the figures for Grundy County show, only a test tells you about one home.

Test kits and monitors42

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Grundy County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Grundy County

Testing

5

Mitigation

3

Explore

Grundy County, Bordering counties

Counties bordering Grundy County

Calculated by Radon411
Why bordering counties matter

5 counties share a boundary with Grundy County, computed from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county’s report can be worth reading alongside this one.

Grundy County, Cities and towns

Cities and towns in Grundy County

The radon figures on this page are for Grundy County as a whole. They do not differ by city or town.

  • Morris
  • Channahon (part)
  • Minooka (part)
  • Braidwood (part)
  • Coal City (part)
  • Dwight (part)
  • Diamond (part)
  • Seneca (part)
  • Gardner
  • Mazon
  • Braceville (part)
  • South Wilmington
  • Godley (part)
  • Carbon Hill
  • Verona
  • Kinsman
  • East Brooklyn

17 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county.

Grundy County, Next steps

What to do next

  1. LearnKnow what radon isWhat radon is, how it gets indoors, and why a county zone is not a reading for your home.Learn about radon
  2. TestTest the building you live inShort-term or long-term, where the device goes, and closed-house conditions.How to test
  3. FixBring a high level downHow a mitigation system works, and the retest that confirms it.How mitigation works
  4. Find a proHire a certified professionalMeasurement and mitigation professionals by state, with their certifications.Find a professional

Informational. Follow EPA guidance. EPA says all radon tests should be taken for a minimum of 48 hours, with windows and doors closed from 12 hours before a short-term test.