Building an ADU in Minnesota

Minnesota has no statewide ADU law

No Minnesota law makes cities allow ADUs. Your city's zoning ordinance decides whether you can add a backyard cottage, a unit over the garage or a basement apartment, and on what terms.

State law lets a city regulate by ordinance "the location, height, width, bulk, type of foundation, number of stories, size of buildings and other structures, the percentage of lot which may be occupied, the size of yards and other open spaces, the density and distribution of population," and the uses of land and buildings. Those general zoning powers are where local ADU rules come from.

The same law says no zoning rule may prohibit modular or industrialized buildings for residential use built under Minnesota Rules, chapter 1361, or manufactured homes built to state standards, if they comply with all other zoning rules. That can matter if you plan a prefab ADU. [1][2][4]

The ADU bills that didn't pass

2026: HF 3895 and SF 4123. These matching bills, introduced in March 2026, would have added a new section 462.3572 to state law. Among many housing changes, they said a city "must allow, at a minimum, one accessory dwelling unit to be built as a permitted use on any residential lot containing a single-family home," regardless of lot size or street frontage, as long as the ADU met emergency access spacing and the smallest residential setback in the district. Cities could still bar selling an ADU separately from the main home. HF 3895 was referred to the House Elections Finance and Government Operations Committee on March 2, 2026, and SF 4123 to the Senate State and Local Government Committee on March 4, 2026. Neither had any further committee action.

2025: SF 2229, the Minnesota Starter Home Act. It would have made ADUs a permitted use in any zoning district that allows homes, except on lots with a duplex or multifamily housing. The Senate housing committee approved it as amended on March 13, 2025, and re-referred it to the State and Local Government Committee. It never got a Senate floor vote.

None of these rules apply to your city unless a future law enacts them. [1][2][3][8][9]

How fast the city must decide: the 60-day rule

Under Minnesota Statutes, section 15.99, an agency "must approve or deny within 60 days a written request relating to zoning" for a permit or other approval. "Failure of an agency to deny a request within 60 days is approval of the request." If the agency denies it, it must give the reasons in writing.

The clock starts when the city receives a complete written request, including the application fee. If your application is missing information, the 60 days start over only if the city tells you in writing, within 15 business days, what is missing. The law allows extensions in some cases.

The rule covers written requests "relating to zoning." Ask your city which of your ADU approvals count as zoning requests and which are building permits. [5]

Temporary family health care dwellings

Since 2016, state law has given caregivers a way to put a small, movable unit on their lot for a relative who needs care. A temporary family health care dwelling must:

• be no more than 300 gross square feet;
• be mostly built off site and not attached to a permanent foundation;
• be universally designed and meet accessibility standards;
• connect to water and electric service;
• have an insulation rating of at least R-15 and a backflow check valve.

It is for one person who needs help with two or more instrumental activities of daily living, certified in writing by a physician, physician assistant or advanced practice registered nurse. It must sit on property where the caregiver or relative lives, meet the main house's setbacks, and only one is allowed per lot.

The permit lasts six months and can be renewed once for six more. The city must decide within 15 days (30 days for a city that meets only once a month), needs no public hearing, and may charge up to $100 for the permit and $50 for a renewal unless its ordinance says otherwise. A city "may by ordinance opt-out" of the law, so check with your city first. [6]

Building code and inspections

The State Building Code "applies statewide" to the construction and alteration of buildings it covers, and it "supersedes the building code of any municipality." Your ADU's construction standards come from the state code, while your city's zoning code sets where it can go and how big it can be.

See our ADU permit process guide for the general steps. [10]

Paying for an ADU: Fix Up loans

Minnesota Housing's Fix Up Home Improvement Loan Program lists "Accessory dwelling unit" among example eligible projects. Loans run from $2,000 to $75,000, with terms of 1 to 20 years and a fixed rate. Key conditions:

• You must own and live in the home for the term of the loan.
• Single-family homes, duplexes, triplexes and fourplexes may be eligible.
• Income limits and a minimum credit score apply.
• You can hire a contractor or do the work yourself.

Your participating lender decides whether your project is eligible. Find one through Minnesota Housing's lender directory on the same page. See our ADU financing guide for other options. [7]

A state nudge for cities: 2025 scoring points

A 2025 law (Laws 2025, chapter 32, section 13) tells the Minnesota Housing Finance Agency, where practicable, to give extra points, up to 5% of the total, to projects in competitive state housing programs if the city meets at least one of eight criteria. One is that the city "allows for duplexes, accessory dwelling units, or townhomes within 50 percent of the area within the jurisdiction zoned for single-family housing." Others include parking mandates of no more than one stall per single-family home and no lot size minimums over one-eighth acre for new single-family homes.

This rewards cities; it does not require any city to allow ADUs. The section expires December 31, 2029. [11]

What to check with your city

Because the rules are local, ask your city's zoning or planning office:

• Which zoning districts allow an ADU, and whether it can be attached, detached or inside the house.
• The maximum size, height and setbacks.
• Whether the owner must live on the property.
• How many parking spaces you need.
• Whether you can rent the ADU short term.
• The permit, plan review and utility connection fees.

The answers differ a lot between cities. St. Paul says "Two ADUs are permitted for each one-family dwelling on a lot" in its RL-H2 and RM1-RM2 residential districts and some others; see our St. Paul ADU guide. Minneapolis handles ADUs through an administrative application plus a building permit, and requires a recorded owner-occupancy covenant only for internal ADUs; see our Minneapolis ADU guide.

Our garage conversion guide, ADU cost guide and tiny house guide cover the general steps. [4][12][13]

Minnesota laws to know

• Minnesota Statutes, section 462.357

  Gives cities the power to zone: regulate building size, height, lot coverage, yards, density and land uses, which is where local ADU rules come from. [4]

• Minnesota Statutes, section 15.99 (the 60-day rule)

  Requires agencies to approve or deny a written zoning request within 60 days; if they don't deny it in time, it is approved. [5]

• Minnesota Statutes, section 462.3593 (2016)

  Lets a caregiver place a small temporary family health care dwelling on their lot with a city permit, unless the city has opted out. [6]

• Laws 2025, chapter 32 (SF 2298), section 13

  Through 2029, gives extra points in competitive state housing programs to projects in cities that, among other options, allow duplexes, ADUs or townhomes in half their single-family zoned area. [11]

• HF 3895 / SF 4123 (2026), proposed ADU and starter home law (not passed)

  Would have required every city to allow at least one ADU as a permitted use on any residential lot with a single-family home; both bills stayed in committee. [1][2][8]

Questions people ask