What a Legal Basement Apartment Costs in Tooele County
Upterra Builders · January 16, 2026
We get this question almost every week here in Tooele County. A homeowner in Overlake or one of the newer north-Tooele subdivisions has an unfinished basement, they know rents keep climbing, and they want to know what it actually costs to turn that space into a legal apartment they can rent out. Here is the honest answer from a crew that has built these across the county for over 20 years.
The Real Number: $45,000 to $110,000
A finished, legal basement apartment in Tooele County usually lands between $45,000 and $110,000. That is a wide range on purpose, because a one-bedroom apartment in a home that already has rough plumbing stubbed in is a very different job than a two-bedroom unit that needs a separate entrance dug out and a full kitchen added from scratch.
Here is roughly how it breaks down by size and finish:
- Small one-bedroom (600 to 800 sq ft): $45,000 to $65,000
- Two-bedroom (900 to 1,200 sq ft): $65,000 to $90,000
- Larger two-bedroom with upgraded finishes: $90,000 to $110,000+
A legal apartment is not just a finished basement with a fridge. It needs its own kitchen, a full bathroom, proper egress, and in most cases a separate entrance. Those four things are where the money goes.
What Drives the Price
A kitchen, not a kitchenette
The kitchen is the single biggest line item after the shell. Cabinets, counters, a range, a hood, and a sink with its own supply and drain lines usually run $12,000 to $25,000 depending on what you pick. You can save real money going with stock cabinets and laminate counters instead of custom.
Egress windows
Every bedroom in a legal apartment needs an egress window and window well large enough to climb out of. Cutting a new egress opening into a poured foundation wall, digging the well, and setting the window runs $3,500 to $6,000 per window here. Homes built with basements already stubbed for future bedrooms sometimes have these framed in, which saves you.
A separate entrance
Most tenants and most lenders want a private entrance. If your basement already has a walkout or a door under the deck, you are ahead. If we have to cut the foundation and build a new exterior stairwell down to a door, budget $8,000 to $18,000 for that alone, including the well, stairs, and door.
Plumbing and the bathroom
If your builder stubbed in plumbing during original construction, which is common in the newer Tooele and Stansbury Park homes, you avoid cutting the slab and you save thousands. A full basement bathroom runs $9,000 to $18,000. Without existing rough-in, add several thousand more for slab work.
Permits and the Tooele County Building Department
A rental apartment is a change of use, not just a finish job, so it gets more scrutiny. You will pull a building permit, a plumbing permit, and an electrical permit, and the county will inspect egress, ceiling height, smoke and CO alarms, and fire separation between the units. Permit and plan-review fees for a project this size typically run $900 to $2,000. Zoning also matters. Not every lot in the county allows a rental unit, so the first call should always be to confirm your parcel is eligible before you spend a dollar on finishes.
Why It Still Pencils Out Here
Even at the top of the range, a basement apartment in Tooele County is one of the few remodels that pays you back every month. With the commute to the Salt Lake valley pushing more renters out to Tooele, Grantsville, and Erda, demand is steady. Done right and permitted, it also adds documented square footage and income that shows up when you sell or refinance.
The wrong way to do it is to skip permits and build a unit that a buyer's inspector flags later. We have been called in to fix plenty of those, and unwinding unpermitted work costs more than doing it right the first time.
Upterra Builders is owned by Danny and Trayson and serves Tooele City, Stansbury Park, Grantsville, Erda, Stockton, and the rest of Tooele County. Licensed and insured in Utah. Call or text (435) 248-0339.