Council Committee Backs Return of Granny Flats

2672-2674 N. 30th St., a house and carriage unit. Photo by Jeramey Jannene.

A once-popular housing type is on the verge of returning to Milwaukee. It’s one of many strategies advocates hope could be a solution to a growing housing affordability crisis.

The Common Council’s Zoning, Neighborhoods & Development Committee unanimously endorsed a plan Tuesday to legalize the development of “accessory dwelling units” (ADUs), commonly called carriage units, rear cottages or granny flats, the latter for their role in intergenerational housing.

It’s that ability to provide intergenerational housing that has Common Council President José G. Pérez backing the proposal. “I think this is a great way for them to pull their family resources together and instead of going far, looking for new houses, leaving the city, we can do ADUs that make sense and that are affordable,” he told the committee.

Examples of historic ADUs can be found in the city’s oldest neighborhoods that ring Downtown. From Bay View to Harambee, small homes can be spotted in alleys beyond larger primary dwellings. Using assessment data, Marquette University researcher John D. Johnson calculated that there are approximately 1,200. Milwaukee is also a national leader in duplexes, though few new ones are built.

The new proposal would allow properties with one or two units of housing to add a third unit, either as a separate structure, an addition or within the existing structure.

“One of the reasons AARP and others are so supportive of accessory dwelling units is that it offers a lower cost housing type than building a single-family home,” said Department of City Development (DCD) planning manager Sam Leichtling. The least costly ADUs, he said, are those constructed with an existing structure. Leichtling said the most likely conversions would be basement-to-second-unit conversions or converting a second-story attic into a separate unit.

Currently, the city does not formally define what an ADU is and requires a complicated application to the Board of Zoning Appeals to attempt to develop one.

But following a national trend, led by Minneapolis in 2014, the city would legalize ADU development. Minneapolis has approved an average of 17.75 new ADUs annually since 2021. West Allis and Wauwatosa have already legalized ADUs.

The Milwaukee proposal would allow the creation of an additional unit without legislative approval, even in areas of single-family homes, but only if design standards are met on size and visual cohesion with the existing unit.

But a key requirement, added by sponsors Pérez and Alderman Robert Bauman, is the restriction that at the time of construction, one of the units on the property must be owner-occupied.

Pérez said that it is designed to ensure ADUs are a tool for families aging in place, not a “tool for absentee landlords.” Bauman, when the City Plan Commission debated the file April 7, said he favors a stronger restriction, but the City Attorney’s Office advised that the time-of-construction is the practical legal limit.

The proposal would, on its face, allow virtually any house in the city to be turned into a duplex, but the design restrictions are intended to prevent a free-for-all. Internal units must be between 300 and 800 square feet in size, proper egress and plumbing infrastructure must be installed and one of the units must be owner occupied.

One of the cosponsors, JoCasta Zamarripa, has lived experience in ADU. “I grew up in a Polish flat in a basement unit,” said Zamarripa of the historic Milwaukee housing style that involved raising up the first floor to create a walk-in basement unit.

Another is living it now.

“I also have an intergenerational household and I would much prefer to have an external ADU,” said cosponsor Peter Burgelis, who lives in a side-by-side duplex.

Code Complications

In explaining the nuances of the International Building Code, Department of Neighborhood Services Deputy Commissioner Michael Mazmanian said it is unlikely that any new ADU would be built as a third unit within or attached to an existing structure. Commercial requirements would be triggered, including the need to add a sprinkler system. “Extremely difficult and costly to meet,” said Mazmanian.

“We anticipate that [third units] would be much, much less likely to be developed within the walls of an existing dwelling because of all of the existing commercial code implications,” said Leichtling. Pérez and Bauman also talked openly of an amendment that would block the addition of a third unit within an existing structure.

“There is anxiety and fear that there will be negative and unforeseen consequences to adopting what on its face seems like a positive, desirable expansion of housing types,” said Bauman.

A stand-alone unit would be judged like a new single-family home on the same lot, said Mazmanian, and would be a more straightforward review. Units above garages could be constructed, but, he said, units built above existing garages are expected to have difficulty with certain building code provisions.

“Even in the cities that have legalized them, they have seen kind of slow uptake,” said Leichtling.

There are certain cost disadvantages that new structures face, including the need to run standalone water and sewer lines rather than extending those serving the existing house. The requirement adds thousands of dollars of costs. “Other municipalities have looked at changing that to reduce the cost,” said Leichtling.

Manufactured homes, including those listed for sale on Amazon, could qualify as ADUs, but they must meet the design standards, and, as the administration officials noted, more significantly, must meet the building code.

“Beyond this piece of legislation, we should be looking at ways to make it easier for people to use tiny homes or shipping containers or things like that,” said Alderwoman Milele A. Coggs.

The ADU concept was first proposed as part of DCD’s Growing MKE plan, which is currently on hold before the council. But Pérez stressed that the council’s ADU legislation, which has the backing of DCD, was separate from Growing MKE. “Growing MKE doesn’t have ownership of it,” he emphasized, seeking to ward off the many community groups that have opposed the city’s plan and a separate “missing middle” zoning change by Bauman and Pérez.

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