Planning an ADU in Murray

Two details set Murray apart before you even get to setbacks. Murray requires homeowners to hire a licensed contractor for an ADU; owner-building is not permitted. And Murray runs its own electric, water and wastewater utilities while banning a separate meter for any ADU. So the first practical question is often not "how big can it be?" but "can the existing service carry a second home?"

Where the ADU opportunity is in Murray

Murray allows ADUs on properties where a single-family dwelling is a permitted use, with a maximum of one ADU per lot. The city's current rules come from a November 2024 amendment (Ordinance 24-26), which Planning Commission minutes describe as increasing the allowable area, reducing parking and reducing side and rear setbacks.

That leaves two paths. Homes with a usable basement or room for an addition can look at an attached or internal unit, which Murray does not cap by floor area. Lots of 10,000 square feet and up can also consider a detached unit, within tighter limits.

ADU types to consider on a Murray property

The code uses two categories, attached (including internal) and detached.

• Basement or internal ADU. Often efficient where a basement already has ceiling height and room for an egress window. See basement ADUs and internal ADUs.
• Attached addition. No ADU floor area cap, but any addition must stay within the zone's lot coverage and setbacks.
• Detached ADU. A single-story backyard unit on a lot of at least 10,000 square feet. See detached ADUs.
• Garage conversion. An existing detached garage can be converted only where it already meets the detached ADU setbacks. See garage conversion ADUs.

Murray's adopted text does not address an ADU above a garage, so that is a question we would put to Planning before designing one.

Property feasibility: what we check first

1. Zoning. Does the zone allow a single-family home as a permitted use? The city directs owners to its zoning map for this.
2. Lot size. Under 10,000 square feet rules out a detached unit, but not an attached or internal one.
3. House size. A detached ADU must be under half the main house's square footage, so a smaller home means a smaller backyard unit.
4. Parking. Can the property hold three off-street spaces in total?
5. Utilities. Can the existing electrical, water and sewer service support a second unit on one meter?
6. Occupancy. Will an owner live in either the house or the ADU as a permanent residence?

Our ADU feasibility review works through these for a specific address.

Murray's ADU rules and permits

The main rules, from chapter 17.78 as amended in 2024:

• Detached size: less than 50 percent of the main house's square footage, and never more than 1,000 square feet. The entire detached structure containing the ADU is also capped at 1,000 square feet, so a garage and ADU under one roof share that limit.
• Detached height: one story, and the lesser of 20 feet or the height of the main house.
• Parking: one additional off-street space, for a total of three. Occupants' extra vehicles must park on site; on-street parking is reserved for visitors.
• Entrances: a separate ADU entrance cannot be on the front yard; it goes to the side or rear.
• Design: a detached ADU must be compatible with the main house's exterior color and materials.
• Owner occupancy: the owner must live in either the house or the ADU and cannot collect rent for the unit they live in. An owner-occupancy affidavit is recorded with the Salt Lake County Recorder as part of the application, and it states that a future buyer must reauthorize the ADU.
• Short-term rentals: neither the house nor the ADU may be rented for less than 30 days at a time. See ADU short-term rental rules.

The ADU Permit is an administrative decision by the Planning Division, not a public hearing. The current application lists an ADU Permit fee of $125, and the city notes that Planning cannot accept electronic payments. Renting the unit may require a Murray business license, listed on the application at $106. A separate building permit is required before any construction or occupancy. Our ADU permitting page explains how we prepare and coordinate these applications, and ADU owner occupancy compares Murray's affidavit with other cities.

Lot and site considerations

Murray's detached setbacks are wider than some neighboring cities: 10 feet from the rear and side property lines and 20 feet from a corner side line, and never in the front yard. On a 10,000 square foot lot with a house set well back, the usable rear area can shrink quickly once those setbacks, the zone's rear yard coverage limit and the parking layout are drawn in.

Because detached units are single-story, the footprint is the whole building, so placement matters more. Any new parking space has to work with the driveway and the side or rear entrance rule at the same time. See ADU parking requirements.

Utility considerations in Murray

Murray City Power is a publicly owned municipal electric utility created in 1913. The city also operates its own water utility, and its wastewater system carries flows to the Central Valley Water Reclamation Facility. Not every Murray address is necessarily served by each city utility, so we confirm the providers for the specific property.

What is certain is the one-meter rule. Separate utility meters for an ADU are prohibited, and the Building Division's inspection checklist asks whether the house has only one address and one utility meter. With the ADU and house metered together, that puts the existing panel size and service line capacity near the top of the list. The city does publish water and sewer impact fees, but none of its fee documents address ADUs, so whether an ADU triggers one is a question for the Building Division and Public Works. See ADU electrical service and ADU utility connections.

The typical Murray ADU process

1. Informal meeting with Planning to verify the zoning district, property lines, utility connection requirements and maximum allowable ADU size.
2. ADU Permit application by email with the checklist, site plan with parking, floor plans, elevations (for detached units or where height changes), the recorded owner-occupancy affidavit and a notarized property owner affidavit.
3. Planning decision, which the application says comes approximately three weeks after a complete application: approve, approve with conditions, or deny. Appeals go to the Hearing Officer within 10 days.
4. Building permit through the city's eProcess 360 portal, with the licensed contractor engaged. The city states its residential code remains the 2021 IRC.
5. Construction and inspection to verify building code compliance. The city's checklist includes items such as interconnected smoke and CO alarms, GFCI outlets and bedroom egress.

See our process for how design and construction fit around these steps.

What drives ADU cost in Murray

The biggest variables are the ADU type, whether the existing electrical service and water line can carry a second unit on one meter, the distance from the house connections to a backyard unit, the added parking surface, and the exterior materials needed to stay compatible with the house. Engineering and fees add to that. Our Utah ADU cost guide explains each driver.

If you are weighing options on a Murray property, the best next step is to See What Your Property Can Support.

Questions from Murray homeowners