Accessory dwelling units in Minnesota

Accessory dwelling units provide additional living space separate from the main house. You could use the unit as additional housing for extended family members to give them both privacy and convenient access. It could be your office or studio space. You could rent it to short- or long-term tenants for extra income. Or you could move into the smaller unit yourself and rent out your house for even more income. In any case, accessory dwelling units provide flexibility and increase density at a time when housing is at a premium. Let’s look at the development of accessory dwelling units in Minnesota.

Minneapolis began to allow accessory dwelling units in 2014 in some neighborhoods, and throughout the city in 2018 as part of a broader move to promote the construction of affordable housing. But they haven’t really caught on. What’s keeping accessory dwelling units out of Minnesota?

While residents of the small homes gush about the charm and lifestyle, the associated regulations and cost — which can exceed $300,000 per unit — have meant the concept has been slow to catch on.—Star Tribune, 24 December 2022

Regulations on accessory dwelling units in Minnesota

Each municipality has its own regulations on accessory dwelling units. That means homeowners must navigate restrictions that vary from place to place. Dakota County, where Beton’s office is located, issued a guide for homeowners last month. As of mid-December 2022, about half the cities in Dakota County do not allow accessory dwelling units at all.

Dakota County municipalities that do allow them require owner occupancy of either the main residence or the accessory dwelling unit. Other regulations govern the minimum lot size and both minimum and maximum sizes of the accessory dwelling unit. All require a total of three or four off-street parking spaces, depending on the city. The maximum number of occupants of the accessory dwelling unit can be as high as six (in Burnsville) or as low as two (in Eagan). Apple Valley limits the number of accessory dwelling units within a certain radius. We’ve discussed previously how such regulation can discourage people from building them.

In Anoka County, Blaine began allowing accessory dwelling units in 2021 and has yet to issue any building permits for them. The city requires a separate HVAC system for the unit and a firewall between it and the primary residence.

In Hennepin County, Bloomington has allowed accessory dwelling units since 2009, but only one has been built there. According to Glen Markegard, the city planning manager, most people inquiring about them want to accommodate extended family. But once they look into the cost, they opt for home renovation instead. That gives them the extra living space, but not the privacy or flexibility of an accessory dwelling unit.

Clearly if we want to see more accessory dwelling units in Minnesota, we need to relax some of these regulations. Harmonizing them across jurisdictions would also help.


However, it’s not regulations alone that drive up the cost. For example, Minneapolis regulates both the height of the accessory dwelling unit and its distance from the main residence. On the small lots typical of single-family urban housing, that usually means building the accessory dwelling unit above the garage. But the garage and its foundation probably weren’t designed to support that load, especially if you want solar panels on the roof. Providing the necessary foundation and structural capacity adds significantly to the cost per square foot.

Building the accessory dwelling unit as part of the original construction brings the cost down to about $100,000. That’s not exactly low-cost housing. However, it may compare favorably to the alternatives for some homeowners. For example, if providing housing for an elderly family member postpones a move into assisted living by a few years, it could be cheap at the price.

We are talking about building a brand new home with all the amenities and components that go into a single-family home, it’s just on a smaller scale. The reality is new construction is expensive, whether it is a full-sized home or an ADU—it isn’t going to be a quick return on investment.—Minneapolis architect Christopher Strom


Video: June Grant, architect, explains how accessory dwelling units can provide additional housing for seniors and others.