The number of accessory dwelling units has slowly increased in Denver, with 58 new permits issued last year and even more in 2019.

The Colorado Sun reports that homeowners are drawn to ADUs for a number of reasons: to create another stream of income, to provide a living space for elderly family members, and to have another asset to pass on to children, among others.

There are approximately 6,000 parcels in the city that would allow for these small, backyard dwellings. But in the absence of broad zoning changes, the permits have to come on an individual basis.

One possible impediment to ADUs is the restrictions localities may put on their use. Homeowners could recover the cost faster by instituting short term rentals (like Airbnb) at first, then transitioning to longer-term leases in the future.

“I like to think of short-term rentals as the gateway drug to more of these units,” L&D Construction president David Schultz told The Sun. “I’ve heard a few council people talking about additional ADUs conditioned on them not being rentals. I think that’s really short-sighted.” 

The U.S. Department of Housing and Urban Development reported that ADUs were common in the early 20th century. However, when suburbs proliferated after World War II and localities saw that low-density housing was in demand, they banned the construction of accessory units.

Complaints about traffic and density are common among ADU opponents, although Denver’s density today is approximately the same as it was in the 1950s.