Property feasibility
ADU Parking Requirements
Stand at the curb and count the places a car can park off the street. That number, and where those spaces sit, decides more ADU projects than most people expect.
Parking rarely comes up in the first conversation about an ADU, and then it decides the plan. A garage conversion removes the garage spaces and adds a unit that needs its own. A narrow lot may have one driveway and nowhere to widen it. Some cities count only spaces that do not block one another. Here is what each city requires, and what state law allows it to require.
The state limits
Internal ADUs. Utah Code 10-21-303 lets a city require one additional on-site parking space for an internal ADU, on top of what the house needs. If the city's code already requires four off-street spaces for the home, it may not require the extra one. A city may also require replacement of garage or carport spaces when the ADU is created there.
Detached ADUs. Utah Code 10-21-304 took effect October 1, 2026. In specified municipalities, a city may not require more than two on-site spaces for a detached ADU of 650 square feet or larger, or more than one for a smaller unit. It may require replacement of parking lost when a detached garage is converted.
ADU parking by city
| City | What is required | Worth knowing | Source |
|---|---|---|---|
| Millcreek | 1 stall per ADU | The city's ADU page says ADU parking cannot be on the street, and a garage conversion works only if the lot can add a space and replace the garage parking with at least one covered stall | Table 18.63-2; city ADU page |
| Salt Lake City | 1 stall | Waived in a zone with no parking minimum, where the property already has an extra stall, within a quarter mile of a public transit stop, or within a half mile of a city bike lane or path | 21A.40.200.G |
| Murray | 1 additional space, 3 off-street spaces in total | Applies to attached and detached ADUs; occupant vehicles parked on site, street parking for visitors only | 17.78.040, 17.78.050 |
| South Salt Lake | Internal: 1 additional, at least 3 in total, none added if the house already has more than 4. External: 1 additional | The house itself needs 2; occupants of an external ADU must park on site | 17.07.070; 17.06.160 |
| Holladay | 1 stall above the city minimum | Spaces lost in a garage or carport conversion must be replaced; outside the home's footprint, the minimum is set by the ADU's bedrooms | 13.14.031 |
| Sandy | Detached: 1 space under 650 total sq ft, 2 at 650 sq ft or more. Attached: no added row beyond the home's base | The base is 2 garage spaces plus 2 in the driveway; modified parking must be replaced on site; street parking for visitors only | 21-11-1; Ord. 26-55 |
| Cottonwood Heights | Internal: 1 additional, at least 3 in total. Detached: 2 additional | No tandem parking; no new front-yard spaces apart from existing driveways; garage spaces replaced if an internal ADU goes in the garage | 19.75.050 |
| Unincorporated county | At least 1 on-site space in addition to the home's parking | Spaces lost to a garage conversion must be replaced | County Code 19.15.060 |
Garage conversions: the double count
A garage conversion is where parking bites hardest. The garage spaces disappear, several cities require them to be replaced, and the new unit needs its own space as well. On a lot with one driveway, that can mean finding room for two or three cars outside the garage. Before planning a garage conversion ADU, sketch where every required car will sit.
Tandem spaces and the front yard
A long driveway can hold several cars, but not every city counts them. Cottonwood Heights prohibits tandem parking, meaning the ADU space may not sit behind or in front of a required space for the house. It also bans creating new parking in the front yard, apart from existing driveways. In South Salt Lake, each parcel is allowed one driveway; a second is possible only in limited cases, such as a corner lot reaching a rear garage, and a circular front-yard drive requires a lot at least 75 feet wide.
When unit size changes the count
Sandy ties detached ADU parking to size, with 650 square feet as the line between one space and two. The state law in effect since October 1, 2026 uses the same line as its cap. Holladay ties parking for units outside the home's footprint to the number of bedrooms. If a design sits near one of these thresholds, parking can be a reason to size it down. See ADU size.
Checking it on your lot
Count the legal off-street spaces you have today, note which ones block each other, and mark where a new space could go without crossing a setback or front-yard limit. Then work through the other questions in Can I build an ADU? Our ADU feasibility review checks parking alongside placement, access and utilities, because a new space often competes with the path to the unit. To start, See What Your Property Can Support.
Questions about ADU parking
Does an ADU need its own parking space?
In most Salt Lake County cities, yes: usually one off-street space on top of what the house already needs. Cottonwood Heights asks for two added spaces for a detached ADU, and Sandy asks for two when a detached unit is 650 square feet or larger. Salt Lake City waives its one-space rule near transit or city bike routes.
Can the ADU's parking space be in the driveway?
Often, but check the details. Salt Lake City's ADU handbook says the extra space could be in the driveway. Cottonwood Heights prohibits tandem parking, where one car blocks another, and bans new parking spaces in the front yard apart from existing driveways.
Can ADU tenants park on the street?
Not as their required parking. Murray and Sandy reserve on-street parking for visitors and require occupants' vehicles to be kept on site. Millcreek's ADU page says no ADU parking is allowed on the street.
What changes for parking on October 1, 2026?
Utah Code 10-21-304 took effect that day. For detached ADUs in specified municipalities, a city may not require more than two on-site spaces for a unit of 650 square feet or larger, or more than one for a smaller unit. Cities may still require replacement of parking lost when a detached garage is converted.