Summit County expands ADU limits to boost workforce housing

Summit County has expanded accessory dwelling units to 1,000 square feet and loosened setbacks, parking and approval rules, with deed restrictions aimed at local residents. The question now is whether those changes will create year-round rentals for workers in Park City, the Snyderville Basin and Eastern Summit County, or mainly give homeowners more room for guesthouses and second-home use.

County planning terms define an accessory dwelling unit as a smaller, independent residential dwelling unit on the same lot as a single-family home, and most zones in Summit County still limit ADU size. Ordinance No. 968, adopted after the 2022 Utah legislative session, said the county had to adopt a moderate-income housing plan and amend its development code in 2024 to add a definition of Internal Accessory Dwelling Unit consistent with state code.

The county had already laid out the basics of that model in a September 2021 presentation. Internal ADUs are permissible under Utah Code Ann. 10-9a-530, staff approves them, and the minimum lot size is 6,000 square feet. That same presentation said the primary residence must be owner-occupied to qualify as an ADU, and short-term rentals are not allowed.

Summit County tightened another part of the market in November 2023, when it banned short-term rentals in guest houses in line with state policy. That matters because the county has long faced pressure from a housing market shaped by tourism, second homes and a limited supply of year-round rentals.

The broader housing target is larger than any single zoning change. A March 2025 Summit County Council agenda document set a goal of facilitating 1,500 new affordable housing units over 10 years, and county housing materials say its programs are designed to serve households earning up to 80% of area median income. A Summit County Housing Authority agenda item also referenced a program to incentivize deed-restricted affordable ADUs.

That is the key reality check for the new rules: the county has made it easier to build accessory units, but the deed restrictions, owner-occupancy rules and rental limits will decide whether the added capacity becomes workforce housing or simply more property-owner flexibility.