Salt Lake City Offers Pre-Approved ADU Plans, but Your Lot Still Gets Its Own Review

A pre-approved ADU plan is not a pre-approved property

Salt Lake City's standard-plan library includes small one- and two-bedroom units and garage-conversion concepts reviewed for minimum building-code compliance. It can be a useful starting point for the right site. The city also says a site review remains required, all permitting fees and documentation still apply, and the building official can require corrections.

That distinction protects the homeowner. A reusable plan cannot know the parcel's zoning, setbacks, utility route, grade, rear-yard coverage, easements, existing accessory buildings or historic status. It also may not match the way the owner needs the space to work.

We compare three routes before drafting: use a city-listed standard plan and complete its site package, adapt a stock plan when the license and geometry permit it, or create a custom plan around the lot. The cheapest drawing is the one that actually fits the property and the owner's goal.

Salt Lake City's ADU envelope has four fast checks

1. Zoning: the property must sit in a district where residential uses are permitted. The city's handbook lists residential, commercial, downtown, form-based, gateway, special-purpose and transit-station zones that can qualify.
2. One-unit limit: only one ADU is permitted per lot, and it cannot be sold separately from the main building.
3. Size and coverage: a detached ADU is capped at the smaller of 1,000 square feet or the main building's size. Accessory buildings collectively cannot cover more than 50% of the rear yard in residential districts.
4. Historic review: a local historic district requires a Certificate of Appropriateness before the building permit path is complete.

Parking is the fifth check when the site is not transit-served. The handbook asks for one additional space, but allows a waiver within one-quarter mile of transit or one-half mile of a bike path. That can change the buildable layout enough to make a detached unit work on an urban lot.

The owner-occupancy and rental rules affect the design brief

For a single-family property, Salt Lake City requires the owner or an owner's family member to live in the main building or ADU. An owner renting one of the units needs the applicable business license and Good Landlord enrollment. The city's residential ADU guidance does not treat a sub-30-day stay as ordinary ADU rent.

Those rules determine who the unit is for. A long-term tenant, an aging parent, an adult child and an owner planning to downsize into the ADU do not need the same accessibility, storage, privacy or parking solution. We document that use before the floor plan hardens.

For a basement conversion, we begin with an as-built that records egress, stairs, ceiling conditions, mechanical space and the existing entry. For a detached unit, we begin with the site envelope and utility assumptions. Both paths reach a floor plan, but they should not start there.

What Apex drafts for Salt Lake City projects

A practical Salt Lake City submittal sequence

1. Look up zoning, local historic-district status and existing permit history.
2. Confirm the ADU configuration, usable site envelope, parking or transit waiver and utility assumptions.
3. Choose standard, adapted-stock or custom drawings based on the parcel rather than price alone.
4. Coordinate survey, structural engineering and historic-review documents when the scope requires them.
5. Submit through the city process, answer plan-check comments and keep revised sheets clearly identified.

The city recommends speaking with Planning and Building Services early, and its One-Stop Shop exists for that purpose. A strong drawing set uses that answer to remove uncertainty before review instead of defending a generic assumption afterward.