Whether for families seeking multigenerational living options, those wanting to carve out space in a tight housing market or investors hoping to generate passive income, accessory dwelling units (ADUs) show no signs of slowing down.

Edina is the latest Minnesota city to allow secondary units (also called small apartments, guest suites or otherwise) on existing residential lots.

Chris Strom of Christopher Strom Architects is not surprised another city has approved this type of housing alternative. He helped the city of Minneapolis planning department with its ADU ordinance language back in 2014, the same year he founded his firm.

"We get multiple inquiries for ADUs every week," Strom said. "It's definitely gaining momentum."

Strom said he's found that the appeal for homeowners is the fact that the self-sufficient units offer an independent living option. Meanwhile, placing them on the same property as a main residence gives a heightened sense of community where things like lawn equipment and other resources can be shared.

"It's truly a lifestyle choice," he said, adding that an ADU doesn't have to be used as a living space and can be used as a pool house or a place of recreation. "Land values in the Midwest has gone up, so it makes sense to capitalize on the land [you have]."

Strom said ADUs are typically 500 to 700 square feet, but they can be smaller or larger, depending on city zoning and housing codes. In Edina, the square footage of an ADU will depend on the size of your lot, with a maximum of 1,000 square feet. In addition, no more than one ADU is allowed per single-family home.

That's more generous than St. Paul, which allows a maximum of 800 square feet (but allows a total of two ADUs per lot). But it's less than Minneapolis, which caps it at 1,300 to 1,600 square feet, depending on lot size, according to Strom, whose firm has two Twin Cities homes featured in "ADUs," a design book by Sheri Koones released this spring spotlighting ADUs across the country.

"I think west Edina has larger lots, so it's more likely that they will have room for ADUs on their property," Strom said.

Like with some cities, ADUs in Edina can be internal (such as a converted attic or basement), attached (such as an addition) or detached from the primary residence.

When building an ADU in general, Strom advised that homeowners keep a few things in mind before building, such as checking local ordinances to make sure it is feasible on your particular property. In Edina, for example, overnight parking is not allowed from November to March, so spaces must be carved out on the lot if there are extra vehicles.

ADUs have to adhere to housing codes, which includes electrical, plumbing and, in the case of Minneapolis, a place to prepare food. All that can add up, Strom said. He estimates construction costs start at $450 per square foot, but usually go up from there.

"Most of the ADUs we do are custom; it's like asking how much a car costs because they range so much in costs," he said. "An ADU costs the same as, if not more, than a regular single-family home."

Edina joins at least 25 other metro area cities that allow ADUs. It joins a list including Minneapolis and Richfield, which both approved ordinances in 2014. St. Paul followed suit in 2018 and St. Louis Park in 2020.

Edina's recent decision to give ADUs the green light is intended to allow residents to adapt to unique family circumstances while aligning with the city's housing and sustainability goals," said Addison Lewis, the city's community development coordinator. The ordinance follows a citywide survey, where about 72% of 136 respondents stated they would support ADUs in their neighborhoods and about 40% said they would add an ADU if allowed.

"As we got into the discussion, one of the main benefits we saw was the flexibility provided to homeowners to meet the needs of their household, including the opportunity for multigenerational living, aging in place or housing for a loved one or caretaker," he said.

Correction: An earlier version of this article said a 50% of respondents of a city survey said they would support an ADU ordinance. It is 72%.