Senate Bill 266, carried by Sen. Trevis, cleared committee on second reading after debate about local zoning, timing and impacts on planning staffs.

The bill would require certain Montana cities to permit triplex and fourplex dwellings by right in zones currently limited to single‑family homes and would prevent zoning rules from treating duplexes, triplexes or fourplexes more restrictively than single‑family residences. The sponsor told colleagues the policy restores an approach the Legislature advanced in an earlier session and grew out of the state’s housing task force as a way to increase supply without additional subsidies.

Sen. Trevis said the measure targets infill where infrastructure exists and includes a delayed effective date (Oct. 1, 2026) to give cities time to implement changes following broader land‑use reforms. Supporters argued the bill helps add housing options where demand has driven prices higher.

Questions from other senators focused on the bill’s block‑level effects and whether a single block could contain single‑family homes alongside duplexes and triplexes. Trevis said the bill does mean a mix of housing types could exist on the same block and that the delayed effective date was intended to ease implementation burdens on local planning staff.

The committee recorded a vote of 33‑17 in favor on second reading. The bill now moves toward third reading on the Senate floor.