Duluth, MN Accessory Structures: ADU Rules (2026)
ADU rules in Duluth, MN, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- ADUs allowed per lot
- One
- Maximum ADU size
- 800 sq ft total floor space
- Height limit
- Height of house or 20 ft, greater
- Separate entrance location
- Rear or side of building only
- Eligible applicant
- Property owner only
- Variances
- Never granted for ADUs
Summary
Duluth allows one accessory dwelling unit per lot under Unified Development Chapter § 50-20.5.E, capped at 800 square feet and no taller than the main house or 20 feet, whichever is greater. Only the property owner may apply, and no variances are ever granted.
E. Accessory dwelling unit. ... An accessory dwelling unit may be created within, or detached from, any one-family or two-family dwelling, as a subordinate use, in those districts shown in Table 50-19.8, provided the following standards are met: 1. Only one accessory dwelling unit may be created per lot; 2. No variances shall be granted for an accessory dwelling unit; 3. Only the property owner, which shall include title holders and contract purchasers, may apply for an accessory dwelling unit; 4. Accessory dwelling units shall contain no more than 800 square feet of total floor space and shall be consistent in character and design with the primary dwelling. An accessory dwelling unit shall not exceed the total floor area square footage of the principal structure; ... ... 7. An accessory dwelling unit shall not exceed the height of the principal residential structure or 20 feet, whichever is greater.
Full Breakdown
8, but only one may be created per lot and only the property owner, including title holders and contract purchasers, may apply. The unit is capped at 800 square feet of total floor space, must be consistent in character and design with the primary dwelling, and cannot exceed the total floor area of the principal structure. If a separate outside entrance is needed for an ADU inside the main house, it must be on the rear or side of the building, not the front. An ADU is never treated as a principal one-family dwelling and must sit on the same tax parcel as the primary one- or two-family home.
Height is capped at the height of the principal residential structure or 20 feet, whichever is greater. The city allows no variances from any of these standards, so an oversized or misplaced ADU cannot be approved through a variance application; the property owner must instead redesign to fit within the standards. These rules were adopted by Ord. No. 10868 on December 11, 2023.
Violations & Fines
Building or occupying an ADU that does not meet § 50-20.5.E, or without required approvals, is a Chapter 50 violation and public nuisance under § 50-39.1.A.1 (activities inconsistent with the UDC). Under § 50-39.4, the property owner and any violator are guilty of a misdemeanor and may be fined as set in City Code § 1-7 or § 12-6, and each day the violation continues after notice is a separate offense.
Frequently Asked Questions
How big can an accessory dwelling unit be in Duluth?
Can I get a variance to build a bigger or closer ADU?
Who is allowed to apply for an ADU permit in Duluth?
Sources & Official References
Other rules in Duluth
How Duluth compares: Easiest Cities to Build an ADU·Compare Duluth to another location·View the Minnesota accessory structures overview
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