A 2024 housing study conducted by the Great Falls Development Authority, NeighborWorks, and The Realty Association found that Great Falls needs 670 new housing units per year — roughly a third of which are new rentals. It is a significant jump from a 2020 study that identified a need for 450 units annually. And city leaders say one solution may already be sitting in people's backyards.
"It's part of the puzzle and it's called ADUs, Auxiliary Dwelling unit," said City Commissioner Joe McKenney.
(WATCH: Could "backyard homes" help solve Montana housing crisis?)
An Accessory Dwelling Unit — or ADU — is a secondary housing unit built on the same property as a primary residence. It can be attached, detached, or built above a garage. In 2023, the Montana Legislature passed Senate Bill 528 with bipartisan support. Sponsored by Senator Greg Hertz and signed into law by Governor Greg Gianforte, the bill requires municipalities to allow at least one ADU on any lot containing a single-family home.
For Great Falls homeowners, that means the option is already available.
"Anyone in our community within the city limits that has a single-family home has permission already by zoning to do an ADU. So, it could be a backyard small house, or it could be an apartment above a garage," McKenney said.
One example already exists in Great Falls — a thousand square foot, three-bedroom, two-bath unit built above a three-car garage. The unit rents for around twenty-four hundred dollars a month or is available to purchase for two hundred and ten thousand dollars.
Seth Haak, owner of Montana Backyard Homes, says the perception that ADUs are just tiny homes is one of the biggest misconceptions holding people back.
"A lot of people, when they first thought about that, it's like, oh, that's a that's a tiny home. Well, that's not really actually the case. They actually allow up to a 1000 square foot home to be built on the property. So, you can actually have up to a three bed, two baths," Haak said.
The uses go well beyond generating rental income. For families navigating aging parents, disabilities, or rising care costs, an ADU can offer a practical and affordable alternative. Haak says the units are customizable and can be completed in as little as 90 days.
He points to one scenario that illustrates the potential.
"Mom is in the process of kind of thinking about we're looking at going to memory care. Memory care is incredibly expensive. So maybe, perhaps a potential option would be like to live in nurse, and they could build a small home on the back side of the property. They're closer to mom," Haak said.
Under Montana law, municipalities cannot require additional parking, impose owner-occupancy requirements, assess impact fees, or set more restrictive building standards for ADUs than those that apply to the primary single-family home on the lot.
ADUs alone won't solve Great Falls' housing crisis — but city leaders and builders say they are an important piece of the puzzle. As more units continue to be built across the state, they could help ease the pressure on a housing market that is struggling to keep up with demand.
