MT · 2023

Montana Miracle Duplex & ADU Laws

SB 323 requires cities of 5,000+ residents to allow duplexes wherever single-family homes are permitted, and SB 528 requires all municipalities to allow at least one ADU per single-family lot. Blocked by injunction in late 2023, the laws were reinstated by the Montana Supreme Court in 2024 and upheld as serving a legitimate government purpose by a district court in March 2025.

Guides for Montana Miracle Duplex & ADU Laws are on the way.