Thoughts on Minneapolis’ Proposed ADU Ordinance

Detached ADUs in Boulder, CO

Detached ADUs in Boulder, CO

Minneapolis folks, the draft ordinance for Accessory Dwelling Units is available! It’s like Christmas-come-early for urbanists. Ok, maybe not that extreme, maybe it’s more like President’s Day? I dunno. Either way, the pace that the city council and planning staff have moved this particular topic through to this point is very encouraging, as is the level of support (92%!) so far from Minneapolitans. That’s insane – I can’t imagine 92% of us agreeing on what color pavement our streets should be, so, good job!


Besides, we’ve already got ADUs (by form) capping many block-ends in the city. This just let’s us build more.

We’ve covered ADUs here only briefly here before, but there are tons of great resources to get yourself familiarized with the concept if you havent already. I took some time over the weekend to read through the draft, and wanted to get a few thoughts out there to make this foray into a new housing option as successful as possible.

A Realist’s Preface

I love ADUs. I want to build one in my backyard. But for all their positives, the realist in me can’t imagine them making a serious impact on the housing market. Look at Portland ADU permits by year (keeping in mind Portland has almost 3x the land area and an already 200k+ larger population than Minneapolis)



Yes, there’s been a jump recently after some policy changes, but we’re talking maybe a couple hundred a year, and less than 1,000 in existence in total. It could be a very long time before Minneapolis sees over 100 permit applications in a year. There’s nothing wrong with that. They can be tricky, expensive, and they need the right lot, location, occupant, personal finances in place to align, but they’re still a valuable tool in the “making Minneapolis affordable, walkable, etc” toolbox.

The Positives

First, let’s call the positives out. I think it’s safe to say that anything we end up with is better than not having ADUs at all, and Lisa Bender  + project staff have done an excellent job getting us to this point. The communication has been clear, and the process wide open with tons of meetings across city neighborhoods. Great job.

I also love that we’re not shying away from multiple forms of ADUs here. Allowing these new units to come from basement or attic space, an addition to a primary structure, or via a detached structure all give options and flexibility. Kudos.



The ordinance also encourages eyes on the alley via requiring 10% of the alley-facing façade to be windows. My gut reaction was “overly burdensome,” but the weekend made me re-think that. This likely won’t be hard to achieve, would have been done in most cases anyway, and really does have some positive benefits to keeping alleys safer (and beautifying them!).

Finally, parking! The behemoth that sinks any productive conversation for new development. I was pleasantly surprised to see that an ADU unit does not come with a requirement to provide off-street parking. The ordinance does require property owners to maintain the minimum parking spaces for the primary structure, which is fair. But exempting the ADU gives flexibility in design, lot placement, and cost for builders.

Room For Improvement

Despite all the positives, I believe there’s still room for improvement to the ordinance in a way that will still get this thing passed. I’m keeping the list fairly short to be pragmatic. In order:

  1. Floor Area – The ordinance keeps the lot coverage of a detached ADU to 676 square feet, or 10% of the lot area (whichever is greater). This is a seemingly arbitrary number that doesn’t really serve much purpose considering permeable surface area requirements by zoning district will remain in place. This seems especially ridiculous when you realize we’re limiting the amount of space available to house humans to the same number as storing cars. If we want to allow for flexible designs and retain owner parking, I suggest removing the maximum or at least making it a number that conforms to some design idea. An example could be: “total floor area can be 750 square feet if a single-story structure OR 800 total square feet with no more than 550 square feet on the ground level.” Just spitballin’.
  2. Height – As drafted, ADUs will be allowed to reach 16′ in height with 11′ high walls. However, 16′ is defined as the midpoint between the eaves and the ridge of the roofline (assuming this definition carries over from detached garage guidelines)
    RoofHeightsFor a hip, gable, or gambrel roof, this makes for a maximum ridge height of 21′. I’m sure this provides for some great designs, but it can still be quite limiting. My guess is most homeowners interested in building an ADU have a vehicle, if not two, and want to retain them. Units above garages will be a natural design fit, and a 21′ roofline with 11′ wall maximum could limit any number of designs that work well in other cities. Plus, it feels kinda bait-and-switchy after being shown designs in the (well-rendered) examples used at project meetings:


    Taller than 21′ on the right?

    Flat roofs should be allowed a full second story (20′), and pitched roofs should get more wiggle room (25′ max?) to allow for large enough habitable spaces on the outer edges where the roof slopes.

  3. Matching Materials – For detachedADUs, this could really hold back projects. Many existing homes don’t have all that great of materials, or conversely, have very expensive materials. We shouldn’t require a structure that will barely be visible (if at all) from the street to match the primary one. In fact, doing so could limit the architectural options and creativity that could really make our alleys more whimsical than today. As a point of reference, both Seattle, WA and Vancouver, BC do not require matching exteriors. As of October 20, 2014, they haven’t been reduced to pits of burning slag (right?).

    via SightlineDaily

    Different, but not necessarily out-of-place. (via SightlineDaily)

  4. Ownership Requirement – I’m not sure why this one made it in. We don’t require single family homes, duplexes, triplexes, or any other units that can legally be rented out to have owner-occupancy for one of the two units (the ordinance does allow the owner to live in the ADU). Why should we require this for ADUs? If we want to limit potential noise or disturbance to neighbors, we should regulate and enforce this the same way we do in other districts, not use some end-around method hoping an on-site landlord will be better.
  5. Exterior Stairs – I snuck this one in. It’s an odd requirement as, again, we don’t limit exterior staircases on multi-family units (duplexes, triplexes, etc). If the city is unwilling to budge on the height and floor area issues stated above (and the exclusion of new street-facing entrances for attached units), the least they can do is allow exterior stairs to maximize finished square footage inside the ADU.

Ok! I’m sure not everyone will agree with me. That’s fine. Use this post as a talking point to reach out to your councilmember. I can’t imagine 92% of city respondents supporting something the way ADUs have been. So before this thing gets passed and we feel like we can’t touch it again for more than a decade, let’s maximize that support to make some minor improvements. Thanks!

16 thoughts on “Thoughts on Minneapolis’ Proposed ADU Ordinance

  1. Alex

    I’m really pleased with the general direction CPED is going with ADUs but also found many nits to pick in the draft ordinance. The website makes it sound like there will be a substantial revision in early November, so make sure to send a copy of this post in to

    I agree with the issues you identified, especially the owner-occupancy requirement, and would add that it seems pointless to limit the size of attached ADUs. If the structure isn’t altered, why does it matter how big the ADU is? If the structure is altered, there are max lot coverage requirements already that will address this issue.

    Regarding the likelihood of ADU construction, I was really hoping the city would create a revolving loan fund dedicated to ADUs to encourage their construction. There is a sound policy basis for this given Minneapolis’ goals to grow the population and housing supply. I’m curious to see construction cost estimates, but I’m guess the city could find room in the budget for a program that would make ADU construction a compelling option financially for those with too-big houses. “Want to never have to scrounge for property tax money ever again? Convert your upstairs into an ADU using this city loan!”

  2. Joe ScottJoe Scott

    There’s one other significant barrier to reaping the full benefits of ADU’s in this ordinance that I can see:

    “546.50. Maximum occupancy. (a) Dwelling units. The combined maximum occupancy
    of a dwelling unit, plus any associated accessory dwelling units, located in the R1
    through R3 Districts shall not exceed one (1) family plus up to two (2) unrelated persons
    living together as a permanent household, provided that the family plus the unrelated
    persons shall not exceed a total of five (5) persons. The maximum occupancy of a
    dwelling unit located in the R4 through R6 Districts shall not exceed one (1) family plus
    four (4) unrelated persons living together as a permanent household, provided that the
    family plus the unrelated persons shall not exceed a total of five (5) persons.”

    The theoretical cap for the total number of occupants of the primary structure plus the ADU, in all zoning districts is 5 “persons”.

    Also, read this sentence again: “…(1) family plus
    four (4) unrelated persons living together as a permanent household, provided that the
    family plus the unrelated persons shall not exceed a total of five (5) persons.”

    Does that mean you can have 5 unrelated roommates, provided one of your roommates has taken it upon themselves to personally constitute a “family?” Do I have to be my own dad and tell myself to clean my room, in character, in front of a social worker? I mean, what the hell are we even talking about here?

    Granted, the city and everyone else already ignores maximum occupancy requirements, and if they didn’t half of south Minneapolis would probably get evicted.

    If the ADU ordinance passed as written, and I built one on my lot, I would be able to rent it to one (1) tenant. How am I supposed to make the financing pencil out for a loan? A potential lender is probably going to look at the letter of the law, and not necessarily be open to the argument that maximum occupancy requirements are never enforced in practice, which would limit the potential income that can be declared on a loan application. This would be a major barrier to building ADU’s in the first place.

  3. Martin

    Hey Alex C., a lot of interesting thoughts here! From my vantage point here in Portland, I’ve also been thinking about the question of “how much of an impact could ADUs have?” in terms of providing environmentally sensible housing.

    The upshot is, they’re not making a big impact in terms of numbers now, but they have a potential for huge numbers, unlike practically any other form.

    You’re right, the numbers of units developed here in Portland (say 200-300 per year at this point) are a drop in the bucket in terms of the tens or even hundreds of thousands of units that need to be developed in the city the next few decades. However, ADUs are unique in that there is a huge potential for them. Practically every single family home in Portland could legally host an ADU. Even if only a third of them are really suited to development, that’s nearly 50,000 construction sites in Portland. Try finding room for 50,000 standard apartment units! ADUs provide a kind of housing people want, without erasing existing single family houses.

    The reason development is slow is partly rules, but partly because ADUs are created by homeowners, not professional developers. That is extremely unusual! Homeowners aren’t used to this job, and they don’t have millions of dollars to throw around. It’s a big struggle and a big deal for a homeowner to create an ADU, so they are not going to dive in quickly, even if the economic rationale from the homeowner’s point of view is sound. There is risk involved as well as benefit. See my post on barriers to ADU development:

    The proposed owner occupancy requirement in Minneapolis just adds to the “risk” side of the equation (it will be harder to move and perhaps to sell the place), so it will probably discourage some would-be ADU developers.

    So — you’re right — it’s very unlikely ADUs will take over Minneapolis soon. But once people see how they actually work, they might choose to loosen things up.

  4. David MarkleDavid Markle

    For a long time I lived in a “mother-lin-law house,” a little “house in back of the house” (without a crescent moon in the door). I loved it; unfortunately the then nabobs of the neighborhood wouldn’t let me invest in it, fix it and keep it. Now the grounds are pretty much unused and relatively “desertified.”

  5. Rosa

    Okay, I am not very good at reading ordinances but is the height requirement still there for an existing building being remodeled into an ADU?

    We have a 2-story carriage house/garage that is easily the size of a small house but it wouldn’t fit the height requirements (I think. I would have to go outside in the dark and measure it to know for sure.) But it’s already there and it certainly matches the house and the neighborhood. Would we be able to make it an actual little house (given tremendous amounts of money, since it doesn’t have plumbing now) as long as we didnt’ change the footprint/current height? Or would the restrictions be the same as for adding a new building?

    1. Alex

      Because you are changing the use the ordinance will apply. But I would guess your chances of a variance are good, since you are working with an existing condition. Make sure to build the extra cost and time of a variance into your planning.

  6. Sam NewbergSam Newberg

    Is it fair to say the owner-occupied requirement is simply a way to make passage of this ordinance more politically palatable, to reduce the fear of slumlords?

    1. Caddy K

      With 92% support for this concept, no it is not fair to say that. It’s also not fair to require it unless that rule is going to apply to all new apartments to prevent fear of “Slum Lords” .

      Does anybody know is there any organized opposition to this at all?

  7. Jim Cain

    This is a crock of BS. The vast majority of people I’ve discussed with do not favor any of this. We don’t want shantyville! Where they found this 92% who favor it is absolutely contrived. I’ve found two people who favor it on multiple blogs and threads outside of this one and hundreds against it. They can’t even control and inspect housing and slum-lords as it is, how can we reliably expect this will be any different. What happens once the property sells? Who keeps the slum-lord blocked from purchasing one. Can you spell “lawsuit”? The council is afraid to pass a zoning law restricting rentals in a given area, how would you expect the same lawsuit they fear couldn’t be used to allow the purchase and construction of these by slum-lords all over the city once you let the cat out of the bag. This is a terrible idea that could severely backfire in pockets around the city slummifying the area. the few people who initially would use it for the right reason would be severely outnumbered by those who would misuse it. I and many other home owners are against this!

  8. Martin

    FWIW, I have a piece of data that may be relevant to the question of whether allowing ADUs creates slums or slum landlords. In Portland, 64% of ADU owners occupied the property, despite the lack of any legal requirement they do so. 36% of properties with ADUs were not owner occupied. So if Minneapolis is similar, and there is no owner occupancy requirement, there would be some investors/small time developers/etc who would create ADUs for financial gain and not live on the site. But the majority of ADU creators would be homeowners who stay put. Hope that helps!

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