Radon mitigation in Rockford, IL
Mitigation means changing a building to reduce indoor radon. In Illinois, anyone paid to do it must hold an IEMA-OHS mitigation license. This independent guide explains how systems work and what to check. It does not design, sell, or install systems.
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- Every key fact linked to IEMA-OHS, EPA or Illinois law
When a Rockford home needs radon mitigation
IEMA-OHS and EPA recommend reducing radon when your level is 4.0 pCi/L or more.[1] EPA bases that decision on a long-term test, or on the average of two short-term tests.[2] In a real-estate test with several foundation areas, IEMA says an elevated result in any one of the lowest areas means the house should be fixed.[3] Not tested yet? Start with radon testing in Rockford.
How radon mitigation systems work
IEMA-OHS says the most common technique is sub-slab depressurization (SSD), which "does not require major renovations."[1] A fan connected to a pipe draws radon from beneath the slab before it enters the house and exhausts it above the highest eave of the roof.[4] EPA calls this a soil suction system and says some radon reduction systems can cut levels by up to 99%.[2]
For crawl spaces and areas over bare soil or rock, IEMA describes sub-membrane depressurization (SMD): a polyethylene sheet is permanently installed over the exposed ground and a fan pulls radon from beneath it.[4] Some homes combine a basement with a crawl space or slab addition, so ask how each area will be handled.
IEMA says mitigation systems reduce radon by changing building pressure differences, collecting radon before it enters and discharging it safely, and diluting it with more ventilation. It does not recommend sealing alone.[4]
What an Illinois radon mitigation system should include
IEMA's printed Guide to Radon Mitigation lists what mitigation systems in Illinois must include:[4]
- effective radon reduction;
- a system function indicator, so you can see the system is running;
- an unobtrusive, permanent installation;
- a primary suction point that is independent of the sump pit;
- quiet, energy-efficient operation;
- sump covers with observation ports; and
- an exhaust above the highest eave, at least 10 feet from windows, doors, or other openings less than 2 feet below the exhaust point, and 10 feet or more from openings in a neighboring building.
The guide is an older IEMA publication. The current licensing rules are in 32 Ill. Adm. Code 422.[5] Ask your mitigator to confirm their design meets the current rules.
Who can install radon mitigation in Rockford
- Illinois law requires an IEMA-OHS license to perform radon mitigation for pay.[6]
- IEMA says its licensed mitigation professionals have passed a radon qualification course and exam, follow an approved quality assurance program, and are audited regularly.[4]
- Look the company up in the IEMA-OHS licensee lookup. Choose license type "Mitigation Professional" and service county "Winnebago." A measurement-only license does not cover installing systems.
- Get two or three written estimates, as IEMA recommends.[4]
New Rockford homes with a passive radon system
Since June 2013, Illinois has required passive radon-reduction features in new homes.[1] IEMA explains that passive and "skeletal" new-construction systems may or may not bring levels below the action level. If a test shows 4 pCi/L or more, a licensed mitigation professional should convert the system to an active one with a fan.[4]
After radon mitigation: test again
IEMA-OHS says post-mitigation testing must be performed to confirm the system works.[1] IEMA's real-estate guidelines call for an independent short-term test with the system running the whole time.[3] Illinois rules generally bar a mitigator from doing both the before and after measurements at the same address unless an independent person does the measuring.[5] Many homeowners use a separate licensed measurement professional or a lab-analyzed kit for the follow-up test.
Questions to ask a Rockford radon mitigator
- What is your IEMA-OHS license number, and does it say "Mitigation Professional"?
- How many suction points, where will the pipe run, and where will it exhaust?
- Is the main suction point separate from the sump pit, and will the sump get a sealed cover with an observation port?
- What indicator will show the system is working?
- What is in the written quote: fan model, sealing, electrical, permits if any, warranty?
- How will the follow-up test be done, and by whom?
- What does the fan cost to run? (IEMA-OHS estimates about $100 a year on average.[1])
Radon mitigation questions from Rockford homeowners
Can I seal cracks instead of installing a system?
IEMA's mitigation guide says sealing alone has not been shown to lower radon significantly or consistently, and it does not recommend sealing by itself.[4] EPA says sealing does make a soil suction system more effective and cost-efficient.[2]
My house has a crawl space. Can it be mitigated?
Yes. IEMA describes sub-membrane depressurization for crawl spaces: a plastic sheet over the exposed soil with a fan drawing radon from beneath it and venting it above the roof.[4]
Can I install a system myself?
IEMA's guide says residents may install a system in their own home, but warns that without the right equipment or know-how you could raise your radon level or create other hazards.[4] Anyone paid to do the work must be licensed.[6]
How do I know the system is working?
Illinois systems must include a system function indicator (a gauge or alarm).[4] IEMA-OHS also says post-mitigation testing must be done.[1]
Questions about radon mitigation in Rockford?
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Sources
- IEMA-OHS, “What is Radon?” (cost, fan energy, action level, SSD)
- U.S. EPA, “A Citizen’s Guide to Radon” (PDF)
- IEMA, “Radon Testing Guidelines for Real Estate Transactions” (PDF)
- IEMA, “Guide to Radon Mitigation” (PDF, older printed guide)
- 32 Ill. Adm. Code 422 (licensing rules; 422.70(j) independent measurement)
- Radon Industry Licensing Act, 420 ILCS 44 (Sec. 25 license requirement; Sec. 40 interference)
Sources reviewed November 14, 2026.