From Empty Lot to ADU: A Step-by-Step Guide
Most ADU guides make the process sound either terrifyingly complicated or deceptively simple. The truth is somewhere in the middle. It's not a weekend project, but it's also not as overwhelming as it can appear from the outside. Here's an honest walkthrough of what the process actually looks like from start to finish.
1
Confirm your zoning and lot size (Week 1)
Before anything else, find out what your parcel actually allows. Call your city's planning department and ask two questions: does your zoning allow a detached ADU, and what are the size and setback requirements? In most Utah municipalities following HB 82, the answer to the first question is yes. The second question gives you the parameters you're working within — minimum lot size, how far from property lines the unit must sit, and any square footage caps.
2
Assess your utility situation (Week 1–2)
A livable ADU needs water, sewer or septic, and power. If your parcel already has utilities stubbed to it, your path is significantly simpler. If not, you'll need to factor in the cost and timeline of bringing utilities to the site. This varies widely by location and existing infrastructure. Get clarity on this early, because it's the variable that most commonly surprises people mid-project.
3
Choose your ADU type and size (Week 2–3)
For most landowners using a modular approach, this means selecting a model. Summit's Wasatch Studio is purpose-built for ADU placements, efficient footprint, premium finishes, and designed for the single-unit rental or accessory use case. The Teton works well for larger lots where you want more space. Your city's size limits will narrow the field. If the cap is 800 sq ft, that determines your options more than personal preference.
4
Sort out your financing (Week 2–4)
ADU financing has gotten more accessible. If you have equity in your primary home, a home equity loan or cash-out refinance is often the cleanest path. Construction-to-permanent loans are also available for ADU projects. Some municipalities in Utah offer ADU-specific financing programs. Salt Lake City's West Side program is one example. Get your financing structure confirmed before you place any orders or pull any permits.
5
Pull permits and pay impact fees (Week 3–6)
This is where timelines vary most by city. Some municipalities process ADU permits in a few weeks; others take longer. Impact fees — the one-time charges cities assess for new units connecting to public infrastructure — are real and need to be budgeted. In Utah County cities, expect $15,000–$50,000+ depending on scope. Your city's planning department can give you a fee estimate before you commit.
6
Factory build and site prep run concurrently (Weeks 4–10)
Once your order is placed with Summit, your home goes into production at our Seminole, Texas facility. At the same time, site preparation happens on your parcel — foundation work, utility connections, access grading. These two tracks run in parallel, which is why modular ADU projects move so much faster than stick-built alternatives. You're not waiting for the build to finish before site work starts.
7
Delivery, set, and final inspections (Weeks 10–12)
The home arrives at your parcel in sections, is set on the foundation, and final utility connections and finish work are completed. Local inspections happen at this stage — and because modular homes are built to the same local codes as stick-built homes, they pass the same inspections. Most ADU placements receive a certificate of occupancy within two to three weeks of delivery.
8
List and rent (Week 12+)
With a certificate of occupancy in hand, you can list the unit. In Utah County and most western markets, well-finished ADU rentals move quickly. Price it correctly for your market, photograph it well, and plan on a short vacancy period. From that point forward, you have a cash-flowing asset on the same parcel you already owned.
Total timeline on a well-prepared parcel: 90–120 days from first zoning call to first rent check. The variables that stretch that timeline are permitting speed and utility installation — both manageable with early planning.
What most people wish they'd known earlier
The landowners who move fastest are the ones who confirm their utility situation and get their financing sorted before they do anything else. Those two items are the most common sources of delay — and neither requires spending significant money to figure out upfront. A call to your city and a conversation with a lender can answer both questions in a week.
If you're at the beginning of this process and want to talk through what it looks like for your specific parcel, that's exactly the kind of conversation we have every day.
Ready to start the conversation?
Tell us about your property and where you are in the process. We'll help you figure out next steps for your specific situation.