Dallas County aligns building code with state law to require passive radon mitigation in new homes

The Board received and reviewed a proposed amendment to the Dallas County construction code to require passive radon mitigation in new single‑family and two‑family homes, aligning county regulations with recently adopted state law.

What the packet says: Staff presented Ordinance 2026‑0016 to add Appendix AF (radon control methods) from the 2021 International Residential Code to the county’s Chapter 47 construction code. The staff report cites Iowa House File 2297, which directs the state to adopt a requirement that new single‑ and two‑family construction include a passive radon mitigation method per IRC Appendix AF. The packet includes the HF2297 text and the EPA radon‑zone map for context.

Why this matters: Iowa is classified as high radon potential (EPA Zone 1). Requiring passive radon systems during initial construction is substantially cheaper and more reliable than retrofitting later; the state law establishes a baseline requirement and county action harmonizes local permitting with the state mandate.

Staff recommendation: Planning and code staff recommended that the Board adopt the county ordinance change so county plan review and building permits reflect the statutory requirement. The packet notes the county’s ordinance will require builders to include passive mitigation provisions (vent pipe, sealed subslab aggregate and membrane, and provision for later fan installation if testing shows elevated radon).

Provenance: Proposed ordinance and staff memo, state House File 2297 text and EPA radon‑zone map included in the June 9 packet (SEG 2843–SEG 2930; HF2297 text SEG 2879–SEG 2899; radon zone map SEG 3011–SEG 3030).