Senate Bill 266 (sponsored by Sen. Trevis) passed second reading after floor discussion highlighting housing supply concerns and implementation timing.

The bill would require certain cities to allow duplexes, triplexes and fourplexes in zones where single‑family homes are allowed, and it would prohibit zoning that forbids those multiunit options in districts that permit single‑family housing. Sponsor testimony and floor remarks framed the bill as a supply‑side approach to Montana’s housing shortage.

Why it matters: Supporters argued SB 266 makes more efficient use of existing infrastructure and adds supply without direct subsidy. Opponents warned about local planning capacity, water/wastewater infrastructure, and that the change may not alone lower housing costs.

Key points from the floor

- Scope and intent: Sen. Trevis described SB 266 as largely restoring language from the 2023 bill (Senate Bill 323) and noted the bill’s delayed effective date so cities can prepare. He said the bill is “meant to increase the supply of housing without subsidies to meet demand.”

- Local planning concerns: Questions from other senators focused on whether the bill would force taller or denser buildings into single‑family neighborhoods and how zoning districts would be administered.

- Effective date: The sponsor and supporters moved the implementation date to Oct. 1, 2026 to allow local governments time to adapt rules and avoid overwhelming planning staffs.

Floor actions and outcome

- Motion to recommend passage — Senate Bill 266 passed second reading on a recorded vote of 33 ayes and 17 nays.

Excerpts from the floor

- “The basic idea is to bring the abatement up to 50,000 from 25,000 ...” (Sen. Trevis made a framing comment while discussing a different bill earlier; on SB 266 he said it is meant to “increase the supply of housing without subsidies.”)

- When asked whether a neighborhood could have a mix of single‑family homes and duplexes/triplexes, Trevis answered, “I believe that is what I'm saying.”

Next steps: The bill goes to third reading if the sponsor pursues final passage. Municipal planners and local governments will need to watch implementation details (definitions and timeline) if the bill advances further.