Radon Levels in Johnson County, Illinois

In 2017, 25.0% of the radon tests reported to CDC for Johnson County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. That is a share of reported tests, not of homes. EPA places Johnson County in Zone 2, moderate predicted potential, a predicted average indoor screening level 2 to 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.

What a radon level means · Radon in Illinois

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 certified tester listed on Radon411 names Johnson County as a service area yet. The Illinois radon program is the place to ask about certified testers and any test kit offer it runs.

How to test a home · Test kits compared · Free and low-cost kits by state · Illinois radon program

No listed mitigator names Johnson County as a service area yet; the Illinois directory lists 387 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.

How radon mitigation works · What mitigation costs · Mitigators in Illinois

EPA places Johnson County, Illinois in Zone 2, which EPA describes as moderate 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.

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.

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.

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.

Johnson County borders 6 counties, derived from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county's report can be relevant.