Saint Paul, MN Accessory Structures: ADU Permits (2026)

Saint Paul legalized accessory dwelling units citywide in 2016 (Ordinance 16-26) within the Family and Larger-Family Residential districts (R1 through RT2). The implementing regulations are codified in Chapter 65 of the Legislative Code (Specific Use Standards) under Title VIII (Zoning Code, Chapters 60-69). Three ADU types are permitted: internal (within the principal dwelling), attached (sharing a wall with the principal dwelling), and detached (separate accessory building). Standards under §65.155: maximum gross floor area of 800 sq ft or 33% of the principal dwelling, whichever is less, for attached/internal ADUs; detached ADUs limited to 800 sq ft or 10% of lot area, whichever is less; maximum height of 22 ft or 1.5 stories for detached ADUs in keeping with accessory-structure standards; minimum side and rear setbacks per the base district (typically 4-6 ft for accessory structures). One off-street parking space is typically required unless waived under transit-oriented criteria. The 2025 1A Zoning Study is currently considering broader missing-middle reforms that may further relax ADU standards. Minnesota HF 4029 (Session Laws 2024 Ch. 124) requires all cities of 10,000+ population to permit ADUs by-right in single-family zones effective January 1, 2025 — overriding more restrictive local provisions. Permits are administered by the Saint Paul Department of Safety and Inspections (DSI). Minnesota State Building Code (Minn. Rules Ch. 1300+, based on 2020 IRC) applies; frost depth is 42 inches.