Rockford Radon GuideIndependent guide · Rockford & Winnebago County, IL

Radon mitigation in Rockford, IL

Mitigation means changing a building to reduce indoor radon. In Illinois, it must be done by an IEMA-OHS-licensed mitigation professional. This site explains the process; it doesn't do the work.

How most systems work

IEMA-OHS says the most common technique is sub-slab depressurization (SSD), which “does not require major renovations.”[1] A pipe and fan draw radon from beneath the floor and vent it to the outside.[2] EPA says some radon reduction systems can cut levels by up to 99%.[2]

Who can do it

After installation: test again

IEMA-OHS says post-mitigation testing must be performed to confirm the system works.[1] Illinois rules generally bar a mitigator from doing the before-and-after measurements at the same address unless an independent person does the measuring. Many homeowners choose a separate licensed measurement professional or a lab-analyzed kit for the follow-up test.[5]

Questions to ask a licensed mitigator

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Sources

  1. IEMA-OHS, “What is Radon?” (cost, fan energy, action level, SSD)
  2. U.S. EPA, “A Citizen’s Guide to Radon” (PDF)
  3. Radon Industry Licensing Act, 420 ILCS 44 (Sec. 25 license requirement)
  4. IEMA, “Guide to Radon Mitigation” (PDF, older printed guide)
  5. 32 Ill. Adm. Code 422 (licensing rules; 422.70(j) independent measurement)

Sources reviewed November 14, 2026.