Accessory Dwelling Units: A Tale of Two Cities

A “carriage house” off Summit Avenue.

About five years ago, interest in accessory dwelling units had reached a critical mass in Minneapolis and St. Paul. ADUs were seen by proponents as a way to increase housing diversity and flexibility and add density in residential neighborhoods. With cities around the country having already approved ADUs, planners and proponents had a wealth of data, ordinances, and best practices to consider. By 2016, both cities had adopted an ADU ordinance. But Minneapolis and St. Paul ended up taking very different approaches and, consequently, have seen markedly different results.

In Minneapolis, Ward 10 council member Lisa Bender introduced an ordinance amendment in June 2014 that would allow ADUs as a permitted use, citywide. Staff held five open houses and used an online survey to gain additional input. With that feedback, staff produced an amendment text that was adopted in November and took effect in December—just six months after the amendment was first introduced. The new ordinance allowed all three types of ADUs—internal, attached and detached—and permitted them to be built on single- and two-family lots throughout the City. Administrative review for ordinance compliance was the only requirement.

Many in Minneapolis acted quickly on this new opportunity. In the first three years, building permits were issued for 92 ADUs—49 interior units (typically basement or attic conversions), 34 detached structures, and 9 attached units. These 92 housing units were added without any necessary new infrastructure, without any public investment, and without any concentrated increase in density. (And, presumably, without much controversy either, given the lack of any recent public debate or opposition to ADUs in Minneapolis.)

In St. Paul, the fate of ADUs could not be more different. There, the most recent ADU planning effort began in 2013, but this was not the first time ADUs had been considered. They were initially included in the 2004 zoning amendments that introduced Traditional Neighborhood zoning, but were ultimately removed due to public opposition. That opposition came particularly from “residents in areas where large lots would have allowed ADUs, such as along Summit Avenue and Mississippi River Boulevard,” according to Planning Commission documents.

The 2010 Comprehensive Plan called for a zoning study to consider “the potential for accessory units in existing neighborhoods,” as a way to “provide a solution for the changing demographics, allowing the elderly to age in place while providing more affordable housing opportunities for singles and couples.” Despite this broad, citywide focus, the zoning study that was actually begun in 2013 looked only at possibly allowing ADUs in the neighborhoods within walking distance of the Green Line, as a means of increasing ridership.

A diagram from Saint Paul’s ADU study.

The 2013 zoning study got bogged down in other issues relating to Green Line zoning, however, and it dragged out until 2016. Meanwhile, neighborhoods outside of the LRT corridor started their own studies, with both Mac Groveland and St. Anthony Park formally taking positions in favor of allowing ADUs in those two neighborhoods (although St. Anthony Park came out against detached ADUs on “neighborhood character” grounds.) Those neighborhoods were not added to the City’s study, however. It was said that the Green Line ADU ordinance would serve as a “pilot study” to determine whether ADUs should be rolled out citywide at some point in the future.

Ironically, support for allowing ADUs along the Green Line was at best mixed. The planning process included public meetings in each of the affected neighborhoods, and opinions on ADUs were divided. By the time the ordinance text was finalized and came to a vote, all of the neighborhoods east of Lexington Avenue had been dropped from the proposal, at the request of Ward 1 council member Dai Thao. In the end, the ordinance that took effect in late 2016 allowed all three ADU types, but in an area of just 3.5 square miles—i.e., one half mile on either side of the Green Line, from Emerald to Lexington. This is barely half of the Green Line corridor, and only six percent of the area of St. Paul as a whole.

Now a year later, it’s hard to see the 2016 ordinance as an ADU pilot study: as of the end of 2017, only one ADU had been approved for construction.

Interest in ADUs remains high in some parts of the St. Paul, and the latest draft of St. Paul’s pending comprehensive plan update calls for consideration of allowing them. But this does not appear likely to result in a citywide ordinance anytime soon. In February, Ward 7 council member Jane Prince introduced a resolution calling for a study of whether ADUs should be permitted in one specific neighborhood in her ward, Mounds Park. Council members in Wards 3, 7 and 9 said they had specific neighborhoods that want ADUs and asked that parts of their wards be included, too. All of Ward 1 wanted in, as well. Prince’s resolution passed with amendments to include the other neighborhoods, but the planning process is not likely to move forward quickly. Staff have indicated that a public meeting will be held in any neighborhood under consideration for ADUs, and the Pioneer Press has reported that coordinating with all 17 district councils would require more planning time and resources than are currently available.

The St. Paul approach makes it very difficult to legislate a citywide ADU policy. Instead of treating the issue as a technical, policy question of whether ADUs should be a permitted accessory use in residential zoning districts, regardless of location, St. Paul’s neighborhood-by-neighborhood approach is likely to result in a patchwork of rules that mean ADUs are permitted in one location but prohibited in another just blocks away… presumably where they don’t fit the “neighborhood character.”

The only ADU built under St. Paul’s Green Line ordinance.

About Mark Thieroff

Mark is a land use attorney in Minneapolis. He and his spouse and two sons live, shop, bike and walk their beagle in St. Paul. Twitter: @markthieroff

9 thoughts on “Accessory Dwelling Units: A Tale of Two Cities

  1. Ian

    I live walking distance from the green line and can’t even build an ADU because i live east of lexington

  2. Parker

    Worth mentioning that Minneapolis has an occupancy requirement for ADUs, meaning that the property owner has to live in either the primary unit or the ADU. Based on the draft STP comp plan language on Page 90, it seems like Saint Paul would want to require something similar.

    The occupancy requirement doesn’t exist in every city where ADUs are permitted. In Los Angeles, for example, a property owner can rent out both the primary unit and the ADU separately.

    1. Mark Thieroff Post author

      The existing St. Paul ADU ordinance includes the same occupancy requirement as Minneapolis–the owner has to live in either the principal dwelling or the accessory dwelling. The St. Paul ordinance also requires the owner to file an annual affidavit attesting to that fact.

    2. Aaron Berger

      Oh wow, I had not noticed that in the regulations before. I have been playing with the idea of building an ADU eventually (like, when I’m not in grad school) because my property is suitable. But I have a hard time imagining that I would ever build something that creates a permanent covenant barring me from selling to an investor or my successor’s successor’s successor from selling to an investor. Given the recency and small number of ADUs in Minneapolis I doubt we have much data on how this affects resale.

  3. Bob Roscoe

    In my architectural experience, I plead guilty to designing two ADUs in Saint Paul, both in the general area of the Summit Hill Neighborhood. Each is generally a block off Summit Avenue. My clients and I submitted plans for a garage with potting shed elements that introduced plumbing and sewer lines to the rear of the properties, then imagination took over.

    Both are very architecturally handsome and very compatible to the rear areas of each property. Oh wait – I just now remember designing a third bootlegged unit in that area.

  4. Serafina ScheelSerafina

    I love ADUs. They provide such flexible living space that can serve different needs at different times. I’ve lived in one off of Summit Ave., and rented a few while traveling. We even bought a property in Minneapolis that had a nonconforming ADU on it, and faced a real challenge trying to get a loan for the property as a result. No one knew how to value it and we had one appraiser give up entirely. The ADU predated our home by more than a century.

  5. Kate Lockhart

    Is it only considered an ADU if it is rented out or occupied by someone other than the property owner? For example, if a property owner built a detached garage with an office space for the property owner’s use, would that be considered an ADU?

  6. Serafina ScheelSerafina

    It needs to be a dwelling unit, with plumbing, kitchen, etc. to be an ADU. The owner can certainly occupy it.


    The “occupancy requirement” requirement can be skirted by having the property in anLLC and renting out the new adu and the existing residence. The renter of either one is a Member of the LLC that holds title to the property as long as he is a tenat. I would like a legal opinion on this.

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