S1353a Allow Duplexes & Twin Homes In Areas Zoned For Single-family Housing

SUPPORT - This bill requires Idaho cities over 10,000 residents to allow duplexes and twin homes anywhere single-family homes are permitted. It limits barriers (lot size, parking, fees), streamlines the approval process, and mandates code updates by Feb. 2027, while preserving health, safety, and infrastructure standards.

This is a meaningful but incremental step toward improving affordability. Legalizing modest density in single-family zones and reducing regulatory barriers, could help increase housing supply and create more attainable homeownership options. However, because it only allows up to two units and applies only to larger cities, the overall impact will likely be gradual rather than dramatic.

This legislation passed in the Senate on March 20, 2026; it was not voted on in the House.