Mother-in-law apartments were seen as a way to boost SLC housing. Is it working?

Not as much as everyone hoped. Only 30 accessory dwelling units have been built in more than three years. But officials are working to speed up construction.

(Salt Lake City Planning Department). New accessory dwelling units — like this backyard unit in Salt Lake City — are seen as a way to ease Utah's housing shortage, but they are not always easy to build.

A much-touted way of easing Utah’s housing shortage is making progress in Salt Lake City — albeit slowly.

More than three years after the City Council adopted its first ordinance encouraging mother-in-law apartments, backyard cottages and other kinds of accessory dwellings in residential zones, only 30 such units have been completed, representing a tiny fraction of the city’s total housing stock.

A new tally from the city’s planning department shows another 17 accessory dwelling units are under construction, and building permits for another 11 are under review at City Hall.

Maps show residents are applying to build them in neighborhoods across the city, including the west side, with notable clusters around Liberty Park, in Central City, Sugar House and on the east bench.

The city has received an average of between 27 and 34 applications yearly for ADUs since late 2018 and hasn’t formally rejected any of them, although 34 ADU applications remain incomplete and, the latest report card says, 16 applications were voided.

Those total numbers remain relatively low, especially against the backdrop of an estimated deficit of 45,000 affordable housing units statewide and a continued campaign of tax incentives and zoning changes by Mayor Erin Mendenhall and the council to boost construction of more housing.

Officials already are seeking ways to tweak their ADU policy to entice more homeowners to consider them.

Current city rules, adopted in late 2018, automatically permit ADUs in neighborhoods already allowing duplexes, triplexes and apartments. But the add-on dwellings are treated as a conditional use in residential areas zoned for single-family homes, meaning they are subject to review and approval by city planners.

Most building-permit applications from residents seeking to build ADUs since late 2018 have fallen into that second category, numbers for 2021 reveal, and that review is now a major and time-consuming feature of the agendas before the planning commission at its biweekly meetings.

City Planning Director Nick Norris said the panel has launched a formal petition to define more ADUs automatically as a permitted use, potentially eliminating the need for public hearings and scrutiny by planners.

The latest report card shows a majority of ADUs built since 2018, when a divided council allowed them almost nine years of debate, have been detached dwellings built in the backyard‚ as opposed to ones constructed inside a primary residence or over a garage.

Numbers also indicate that mix shifted slightly toward internal ADUs in 2021, after the Utah Legislature passed a law permitting such dwellings inside all existing homes across the state, with limited exemptions.

Salt Lake City’s new ADUs have had an average size of between 540 and 566 square feet, usually with one bedroom, and have ranged in height from just over 14 feet to 17.5 feet, according to the city’s tally. Both those measures are less than city zoning permits.

The report doesn’t include data on the cost of construction, which residents seeking to build ADUs often cite as a major obstacle.

Planners have recommended other reforms to city policy, including setting a yearly goal for the number of ADUs built. They also have suggested, among other things, removing requirements that ADUs be owner-occupied and regulations on parking and how far backyard ADUs must be set back from property boundaries.

Colin Jube, co-founder and CEO of Modal Living, a supplier of modular living units, said cost continues to be a major barrier, one worsened by a recent spike in the prices of basic building materials such as lumber and steel.

Jube has estimated that city impact fees and permits on ADUs have ranked among some of the highest in the country, adding as much as $10,000 to $12,000 to total costs.

The city recently adjusted impact fees it charges for building ADUs, shaving total fees by about $2,200 by treating them more as apartment units that stand-alone homes. But those who pursue them often say that meeting other city requirements, including new sewer lines, often push prices skyward.