New Construction Radon Systems in Ames, IA

New construction radon in Ames, IA changed two weeks ago. House File 2297, signed in May 2026 and effective July 1, 2026, requires every newly built single-family home and duplex in Iowa to include a passive radon mitigation system: the vent pipe, roughed in from below the slab to above the roof, built into the house from day one. It passed the legislature almost unanimously, which tells you how settled the underlying question is in the highest-radon state in the country.

What the law does and doesn’t do

A passive system is the pipe without the fan, relying on natural stack draft to move soil gas. It helps, and in some houses it’s enough. But Iowa’s glacial-till geology is why the state averages 8.5 pCi/L indoors, and a Zone 1 county doesn’t grade on effort. The law mandates the infrastructure, not the outcome: nothing in HF 2297 requires the finished house to test under 4.0. That last step belongs to the homeowner, and it’s cheap now precisely because the expensive part is pre-built. Activation means adding an inline fan to the existing pipe, wiring it, mounting a manometer, and retesting. Least invasive job in the trade.

The Ames before/after line

Here’s the detail that matters for anyone shopping new construction in Story County: before July 2026, this county had no local radon-resistant construction requirement. Only a handful of Iowa jurisdictions did, and Story County wasn’t among them. So Ames’s new-build landscape splits cleanly. Homes permitted under the new law get the pipe. The thousands of houses built in Scenic Valley, Northridge Heights, Somerset, and Ansley’s earlier phases in the years before it get nothing by default, and they sit on the same till as everything else. Pre-law new construction retrofits the standard way (sub-slab depressurization, four figures); post-law construction activates for less. Either way, the test is the starting point.

For builders and buyers both

Builders working Ames’s active developments are installing these systems as routine now, and mitigation-side questions come up: pipe routing that will actually draft, sealed sump lids, labeling, and what happens when a buyer’s first-winter test still reads high. Buyers should treat the first closed-house season (roughly November through April here) as the real exam: run a 48-hour test, read the number, and finish the system if the number says finish it.

Straight answers on the new law, activations, and retrofits across Ames, Nevada, Story City, Huxley, Gilbert, and Slater. Iowa credentials the people who do this work (Code 136B), so whoever you call, ask for the credential. Then call.