What Permits Do I Need to Build an ADU in Cache Valley?
- 2 days ago
- 5 min read
What permits do I need to build an ADU in Cache Valley? It's one of the first questions homeowners ask when they start thinking seriously about adding an accessory dwelling unit — and getting the answer right before you spend money on plans or materials can save you significant time and frustration. The permit process in Northern Utah is manageable when you know the steps. Here's exactly how it works across Cache Valley municipalities.
Step One — Zoning Verification
Before you spend a single dollar on plans, drawings, or contractor conversations, the first thing you need to confirm is whether your property is zoned to allow an ADU.
In Logan, Providence, Nibley, and most Cache Valley cities, ADUs are permitted by right in residential zones as long as your property meets the applicable standards. Utah state law has pushed municipalities to allow ADUs in residential zones, and most Cache Valley cities have adopted ordinances that make the process relatively straightforward for properties that qualify.
But every city has its own ordinance and its own process. Logan City has a dedicated ADU application through their Community Development Department — you can download their factsheet directly from the Logan City website. Providence, Nibley, and some smaller Cache Valley municipalities may route you through the Cache County Building Department rather than a city building department for the permitting phase.
The first call you make is to your city. Confirm that ADUs are permitted in your specific zone and ask what their process looks like from the beginning. That one conversation saves you from designing plans around a project that might not be approved where you live.
One thing worth checking before you even make that call — if your property has an HOA, review your CC&Rs first. HOA restrictions in Cache Valley sometimes go beyond what the city allows. A city permit does not override your HOA rules. Confirm both before you commit to a plan.
Step Two — The Site Plan
Once you've confirmed zoning approval, the city is going to want to see a site plan before anything moves forward.
A site plan is a drawing that shows your property boundaries, the location of your existing home, and where the proposed ADU will sit on the lot. What the city is reviewing is setbacks — making sure your ADU maintains the required distance from all boundary lines. In most Cache Valley municipalities, detached ADUs need to sit at least four to six feet from rear and side property lines, though requirements vary by city and zone.
Getting your site plan right upfront is important. If your proposed placement doesn't meet setback requirements you'll be redesigning before you can move forward — which costs time and money that could have been avoided with a quick check at the start.
This is also the stage where the city confirms your lot qualifies for the ADU you're proposing. Size of the lot, existing square footage, and other factors may affect what's approvable. Work through this phase carefully before investing in full engineered plans.
Step Three — The Building Permit
Once zoning clears you, the next step is the building permit. This is where your engineered construction documents come in.
The city needs detailed plans before they issue a building permit — not a sketch, but actual engineered drawings that show the structure, the systems, and how everything meets current building code. This is why we always recommend budgeting an additional $2,500 to $4,500 for architectural or engineering drawings before construction costs are even factored in. It's a soft cost most homeowners don't anticipate, and it's non-negotiable.
Some Cache Valley cities have their own building departments. Others, like some of the smaller communities, route permits through the Cache County Building Department. Either way the process is fundamentally the same — submit your plans, pay the permit fee based on the project's construction value, and wait for approval before breaking ground.
Do not start construction before the permit is issued. That is how you end up with a stop work order, potential fines, and the possibility of having to tear out completed work so an inspector can verify what was done. It is never worth it.
Step Four — Inspections at Every Phase
Once the permit is issued and construction begins, inspections happen at multiple phases throughout the build. This is standard on any permitted ADU project in Cache Valley.
Rough framing gets inspected before walls are closed. Rough electrical, rough plumbing, and HVAC rough-ins all get inspected before insulation and drywall go up. Insulation gets inspected. And a final inspection happens when the project is complete and the ADU is ready for occupancy.
Each inspection is a checkpoint that confirms the work meets current building code before the next phase begins. Skipping or rushing through inspections isn't an option on a legitimate permitted project — and it shouldn't be. The inspection process is what makes an ADU legal, safe, and insurable.
On every ADU project we run, we handle the entire permit process from the first application to the final sign-off. We schedule every inspection, meet the inspector on site, and manage the city relationship so our clients practically never have to interact with the building department directly.
Frequently Asked Questions
Do all Cache Valley cities have their own building departments for ADU permits?
Not all of them. Larger cities like Logan have their own Community Development and Building Departments that handle ADU applications and permits directly. Smaller municipalities in Cache Valley, like Providence, may route permitting through the Cache County Building Department instead. The first step is always to contact your specific city to understand which department handles your permit and what their process looks like.
How long does the ADU permit process take in Cache Valley?
Plan on a minimum of two to four weeks for the permit review process in most Cache Valley municipalities, and potentially longer for more complex projects. The timeline depends on the city, the complexity of the plans, and how complete your application is when you submit it. Having fully engineered plans and a complete application package ready at submission is the single best thing you can do to avoid delays in the review process.
Can I build an ADU if my property has an HOA in Cache Valley?
Possibly — but you need to check your HOA's CC&Rs before you apply for anything. Utah state law prevents HOAs from banning internal ADUs outright, but external detached ADUs may still be subject to HOA restrictions. A city permit does not override your HOA rules. Confirm both your city's zoning approval and your HOA's position before investing in plans or a contractor.
