Accessory dwelling units (ADU)

Accessory Dwelling Units (ADUs) are small independent housing units on the same lot as a stand-alone single-family residence with a kitchen, bathroom and areas for living and sleeping. ADUs can be attached or detached from your primary residence, and can be either converted within an existing structure or new construction. ADUs are also commonly referred to as carriage houses, accessory apartments, garden apartments, mother-in-law suites and granny flats.

ADU Pre-Reviewed Plans: Available for Download

The Lake City Port Authority, in collaboration with the Coalition for Rochester Area Housing, hired TRImension Design from Lake City, MN to design pre-reviewed plans for five types of Accessory Dwelling Units. The plans have been reviewed by TRImension staff and Port Authority staff. If you are interested in designing or building an ADU, you can utilize these plans as a starting point or your final proposed plans. All plans will need to be submitted, reviewed and approved by the City’s Department of Planning & Community Development, as well as the City’s building officials. The Port Authority’s involvement in this project was funded through a grant from AARP. The five plans are available for download below are:

    • 392 Sq Ft Lofted Guest Cottage
    • 532 Sq Ft One-Bed Detached Cottage
    • 780 Sq Ft Two-Bed Detached Cottage
    • Two-Stall Garage Lofted Guest Cottage
    • Three-Stall Garage Lofted Guest Cottage
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General ADU Information

  1. Expands Housing Options: ADUs provide more housing options in neighborhoods that are already built out, which can help relieve the growing demand for housing in a way that does not alter the character of existing neighborhoods. ADUs are able to house people of all ages, offering young people entry-level housing choices, enabling families to expand beyond their primary home and giving empty-nesters the chance to downsize while remaining on their property and generating rental income from the primary residence.
  2. Generates Stream of Income: If you are renting out your ADU, the rental income may make it possible to cover the cost of monthly loan payments and, over a number of years, pay back the initial cost of the ADU’s construction. Even when financial returns are not a primary motivation, earning rental income might make it possible to work part-time, stay home with a child or save for a major expense.
  3. Allows for Aging in Place and Downsizing: An ADU provides an opportunity for homeowners to remain on their property in a smaller space as they age, while their adult children move into the main house or they rent out the main house for extra revenue in retirement.
  4. Provides Space to House Friends, Family and Caregivers: ADUs can provide independent lodging or living space for friends, family members and caregivers. Many homeowners are motivated to build their ADU to provide a combination of in-home care and independent living for a family member. The cost of ADU construction and maintenance may be comparable or less expensive than some assisted-living or skilled-nursing facilities, with the added benefit of keeping a loved one close.
  5. Reduces Environmental Impacts: ADUs tend to be environmentally-friendly simply because they are smaller and use less energy for heating, cooling and light. Energy-saving designs can be incorporated into an ADU, further lowering its environmental impact.
  1. Internal: ADUs are located within the structure of the main house with a separate entrance; examples would be converted attics or basements.
  2. Attached: ADUs share one or more walls with the primary house; examples would be additions or conversions of attached garages.
  3. Detached: ADUs are the most visible type of ADU, and are a separate structure completely removed from the primary dwelling; examples would be backyard structured, detached garage conversions, same-level additions to attached garages and above-garage units. 

ADU Examples

Per Lake City’s Code of Ordinances (Title XV - Land Use - Chapter 155: Article 9 Residential Districts), Accessory Dwelling Units (ADUs) are permissible. ADUs are intended to be developed in Low Density Residential, Medium Density Residential and Traditional Neighborhood Districts. Specific to ADUs or Secondary Dwellings, Lake City’s Ordinance specifically reads:


“The purpose of a secondary dwelling is to provide life-cycle housing opportunities for family members or small households of one or two people, while providing more efficient use of large single-family dwellings or large lots.


  1. A secondary dwelling unit may be located within a principal structure used as a single-family detached dwelling, above a detached garage, or within a separate detached structure.
  2. There shall be no more than one secondary dwelling unit on the zoning lot.
  3. At least one dwelling unit on the zoning lot shall be owner-occupied.
  4. The minimum lot area shall be two thousand five hundred (2,500) square feet greater than the minimum lot area required for a single-family dwelling in the zoning district.
  5. If the secondary unit is included in the principal building, the appearance of the building shall remain that of a single-family dwelling. Any new or additional entrances must face the side or rear of the building.
  6. Whether the secondary unit is an addition to an existing structure or a new detached structure, roof pitch, windows, eaves and other architectural features must be the same or visually compatible with those of the principal building. Exterior finish materials and trim must be the same or closely match in type, size and location the materials and trim of the original building.
  7. A secondary unit within the principal structure shall not contain more than thirty (30) percent of the principal building’s total floor area or eight hundred (800) square feet, whichever is less. A detached secondary unit shall not exceed one thousand (1,000) square feet in gross floor area.
  8. Impervious limits for the lot within the zoning district in question shall not be exceeded.”

ADUs will require a Conditional Use Permit and are subject to all lot dimension, setback and impervious coverage restrictions, as well as any additional applicable regulations. To gather more specific information on regulations and the approval process, please reach out to the City’s Planning & Community Development Department.


Additional Information:

Lake City Zoning Map

Title XV - Land Use - Chapter 115: Article 9 Residential Districts

ADU Informational Panel

In 2023, the Lake City Port Authority was awarded an AARP Demonstration Grant to raise awareness around Accessory Dwelling Units (ADUs) and their benefits in the Lake City community. As a component of this grant, the Port Authority hosted informational panels on July 26, 2023 with the following presenters:
  • Jay Haapala, Community Engagement Specialist, AARP Minnesota
  • Jamie Stolpestad, Partner, YardHomesMN
  • Megan Smith, Director of Planning & Community Development, City of Lake City
Watch the recording of Jay and Megan’s presentations to learn about what ADUs are, the benefits of having an ADU, and the process of getting an ADU approved in Lake City. If you have questions, please reach out to the Port Authority and our staff can assist you.

ADU Interest Form

Interested in building an ADU on your property? Let us know! Fill out the form below and Port Authority staff will send you additional information on Accessory Dwelling Units and the process of building an ADU on your property in Lake City. We will not share your contact information with anybody without your explicit permission.