We Handle Every Permit So You Don't Have To
ADU permitting in Twin Falls involves a Zoning Use Permit application, multiple trade permits, and weeks of follow-up across city departments. We manage the entire process from first submission to Certificate of Occupancy.
Why ADU Permitting Is Complicated
An ADU in Twin Falls isn't just one permit — it's a Zoning Use Permit application ($250 for ADUs), a building permit, electrical permit, plumbing permit, mechanical (HVAC) permit, utility connection permits, and impact fee payments. Each has its own application, its own review process, and its own inspection schedule.
Idaho follows the 2018 International Residential Code (IRC), and Twin Falls enforces additional ADU-specific requirements under Title 10-6-10. Getting it wrong means delays, re-submissions, and potentially costly plan changes. Incomplete applications are not accepted or scheduled for review by the city.
ADU Requirements — Twin Falls Title 10-6-10-B
Per Title 10-6-10-B, your ADU must not exceed 45% of your principal residence's living space, must match the existing roof pitch, siding, and windows, and must share water/sewer/sanitation with the primary dwelling (no separate utility meters are permitted). One additional off-street parking space is required. Setbacks for the ADU follow the same requirements as the principal building.
What We Handle:
- ✓Zoning Use Permit application — completed, signed, and submitted with the $250 ADU fee to Twin Falls P&Z
- ✓Proof of property control — deed, title report, or purchase agreement as required by the application
- ✓Title 10-6 compliance documentation — verifying your project meets all zoning standards
- ✓Written project description — detailed narrative of scope, use, and construction approach
- ✓Scaled site plan — 8.5"x11" with measurement scale, property lines, north arrow, street names, and color elevations for new buildings
- ✓Trade permits — electrical, plumbing, mechanical (HVAC)
- ✓Impact fees — approximately $6,000-$10,000 depending on size and jurisdiction
- ✓All inspections — foundation through final CO
Twin Falls 7-Step Zoning Use Permit Process
The City of Twin Falls follows a formal 7-step application and decision process for Zoning Use Permits. We manage every step on your behalf.
Detached Accessory Building Setbacks (Title 10-6-10-A)
Setback requirements for detached accessory buildings depend on building height and zoning district. Buildings 15 feet or under follow simplified setbacks; buildings over 15 feet must comply with district-specific requirements.
| Height / District | Front | Side | Rear | Max Height |
|---|---|---|---|---|
| 15 ft or under (all districts) | 20' | 3' | 3' | 15' |
| Over 15 ft — TN-1 | 20' | 7' | 20' | 35' |
| Over 15 ft — TN-2 / TN-3 | 20' | 5' | 15' | 35' |
| Over 15 ft — All other districts | 20' | 5' | 15' | 35' |
Source: Twin Falls Municipal Code, Title 10-6-10-A — Detached Accessory Building Setbacks
Inspection Stages We Coordinate
Twin Falls Planning & Zoning
203 Main Ave E, Twin Falls, ID 83303
Phone: (208) 735-7267
Email: tfplanning@tfid.org
Zoning Use Permit applications and zoning questions
Twin Falls Building Safety
Phone: (208) 735-7238
Building code and inspection questions
Idaho Law Is on Your Side
Idaho House Bill 166 prevents jurisdictions from imposing outright bans on ADUs. And as of July 1, 2023, HOAs cannot create or enforce rules that generally ban ADUs on detached, owner-occupied properties. Learn more about your rights →
Our Permitting Process
A streamlined approach that minimizes delays and gets you building faster
Document Preparation
We compile proof of property control, Title 10-6 compliance documentation, a written project description, and a scaled site plan with color elevations — every item required by Twin Falls Planning & Zoning.
Application Submission
Complete Zoning Use Permit application ($250 fee) filed with Twin Falls P&Z, along with building permit, trade permits, and utility connection applications. Incomplete applications are not accepted or scheduled for review.
Plan Review + Decision
We respond to reviewer comments and coordinate through the city's 7-step review process. Our code-compliant plans minimize review cycles. Decisions include a 15-day appeal window per city procedure.
Permit Issuance + Inspections
Once approved, we manage all inspections throughout construction: foundation, framing, rough-in, insulation, and final inspection for Certificate of Occupancy.
Let Us Handle the Paperwork
Permitting is one of the most confusing parts of an ADU project. Start with a free Readiness Call and we'll guide you through every step.