Test before you spend anything
The cheapest correct first step is not a contractor visit. The Johnson County K-State Research & Extension office at 11811 S. Sunset Drive, Suite 1500, Olathe sells DIY radon test kits for roughly $8–15, lab analysis included. Call 913-715-7000 to confirm stock.
We say this before quoting because in a county averaging 5.3 pCi/L, you are testing to size a problem rather than to discover whether one is plausible. Pay a professional when the number has to hold up for somebody else — a home sale, a post-mitigation verification, or a disputed earlier result.
Why Johnson County tests high
Eastern Kansas sits on fractured limestone and shale. Uranium occurring naturally in that rock decays, and one decay product is radon gas, which travels through soil and fractures until it meets the underside of a building. Lenexa shows the geology at scale — the National Archives stores federal records in excavated limestone caverns beneath the city.
What turns soil gas into an indoor problem is the house. The usual entry points we find here:
- Unsealed sump pits — an open pit is a direct path from the drain tile to your living space
- Block foundation walls — hollow cores behave as a chimney, drawing gas up inside the wall
- Slab-to-wall joints and cracks opened by seasonal clay movement
- Crawl space additions with bare dirt floors, common on 1980s expansions
What we do
- Radon Testing — Certified short-term, long-term and continuous monitor testing — plus honest advice about when a $10 DIY kit is the better buy.
- Radon Mitigation — Sub-slab depressurization done properly — sealed entry points, correctly sized fan, discharge above the roofline, and a verification test that proves it worked.
- Fan Replacement & Repair — Radon fans fail silently after 5 to 10 years. We test the existing system, replace the fan, and verify the level actually came back down.
- Crawl Space Mitigation — Sub-membrane depressurization for dirt-floor crawl spaces — sealed polyethylene barrier, suction beneath it, and a verification test.
- Real Estate Testing — 48-hour continuous monitor testing with an hour-by-hour report, scheduled around inspection deadlines, plus straight answers on who usually pays.
How mitigation works
Radon mitigation is a pressure problem, not a filtration problem. Nothing gets cleaned. Sub-slab depressurization makes the soil beneath your slab lower-pressure than your basement, so gas moves outward instead of inward.
- Diagnostic visit. Foundation type, sump condition, wall construction, and a check for existing passive pipe. This determines suction points, and suction points determine price.
- Fixed written quote. One number, before anything is installed.
- Install. Suction point through the slab, sealed pipe to the exterior, inline fan discharging above the roofline, sump sealed with a gasketed cover, manometer fitted to the pipe.
- Verification test. A post-mitigation measurement proving the level dropped below 4.0 pCi/L. Without it you have a pipe, not a result.
Already have a system? Check the manometer — the small clear U-tube on the pipe. If the liquid sits level in both columns, your fan has stopped and radon has returned.
Call (913) 555-0147Kansas requires certification — verify it
The Kansas Radon Certification Law was passed in 2010, effective 2011 and requires current KDHE certification for any radon testing or mitigation performed for hire. Uncertified paid work violates state law. Certification runs in two years terms, and Kansas accepts NRPP or NRSB national credentials.
Statute K.S.A. 48-16a10 additionally requires certified contractors and labs to report measurement data to the state quarterly — which is why Kansas has over 46,000 measurements on record rather than a voluntary sample. Verify any certification number with the KDHE Radon Program at 785-296-1560 or kdhe.radon@ks.gov.
Areas we cover
Common questions
What is the average radon level in Johnson County?
Johnson County homes average 5.3 pCi/L, above the EPA action level of 4.0 pCi/L. The county is designated EPA Radon Zone 1, the highest-risk category. Kansas statewide averages 4.9 pCi/L.
Does a radon contractor in Kansas have to be certified?
Yes. The Kansas Radon Certification Law, effective 2011, requires current KDHE certification for any radon testing or mitigation performed for hire. Uncertified paid work violates state law. Ask for the certification number and verify it with KDHE at 785-296-1560.
Where can I get a cheap radon test kit?
The Johnson County K-State Research and Extension office at 11811 S. Sunset Drive, Suite 1500, Olathe sells DIY kits for about $8–15 with lab analysis included. Call 913-715-7000 to confirm pricing. For most homeowners that is the right first step.
How long does a radon mitigation system take to install?
A typical home with one basement foundation takes about one day. Homes with a crawl space addition, multiple foundation types, or a finished basement that complicates pipe routing take longer and may need a second suction point.