ADU (Accessory Dwelling Unit) Permit in Boise (2026)
ADU (Accessory Dwelling Unit) permit requirements, fees, and process for Boise, ID. Find out if you need a permit and how to apply.
Yes, a ADU (Accessory Dwelling Unit) permit is required in Boise, ID.
A ADU (Accessory Dwelling Unit) permit is required in Boise, ID. The Boise Planning and Development Services — Building Division handles permit applications for Boise. Below you will find the current thresholds, fees, and process for obtaining a adu (accessory dwelling unit) permit in Boise.
When Is a Permit Required?
When a ADU (Accessory Dwelling Unit) Permit Is Required in Boise: All ADUs require building permit
Permit Fees
ADU (Accessory Dwelling Unit) Permit Fees in Boise: $1,500-$6,000 typical. Estimated timeline: 4-8 weeks plan review.
Estimated timeline: 4-8 weeks plan review
How to Get a ADU (Accessory Dwelling Unit) Permit in Boise
Verify whether your project meets the permit threshold in Boise: All ADUs require building permit.
Prepare your permit application and plans. Contact the Boise Planning and Development Services — Building Division at https://www.cityofboise.org/departments/planning-and-development-services/ for required documentation.
Submit your application online at https://www.cityofboise.org/departments/planning-and-development-services/building/permits/ or in person at the Boise Planning and Development Services — Building Division.
Pay the permit fee: $1,500-$6,000 typical.
Wait for plan check approval. Estimated timeline: 4-8 weeks plan review.
Schedule required inspections through https://www.cityofboise.org/departments/planning-and-development-services/building/inspections/. All inspections must pass before project is finalized.
Important: ADUs processed by Boise Planning and Development Services. Online permit portal available.
Additional Requirements
- Water/sewer connection fees may apply
- Compliance with Idaho Energy Code required
Boise Planning and Development Services — Building Division
Phone: (208) 384-3830
Website: https://www.cityofboise.org/departments/planning-and-development-services/
Online Permits: https://www.cityofboise.org/departments/planning-and-development-services/building/permits/
Hours: Mon-Fri 8:00am-5:00pm
Frequently Asked Questions
Can I build an ADU in Boise?
Yes. Boise allows ADUs (accessory dwelling units) through its local zoning code (City Code Title 11). You can build a detached or attached ADU on most residential lots. Idaho does not have statewide ADU preemption, but Boise has adopted permissive local ADU allowances. Detached ADUs are limited to 1,000 sqft. No owner-occupancy requirement applies. Permits are processed by Boise Planning and Development Services.
Does Boise require a permit for short-term rentals?
Yes. Boise requires a Short-Term Rental License ($125/year) for all Airbnb-style rentals. An annual fire safety inspection is also required. The license number must be displayed on all listing platforms. Airbnb and VRBO collect and remit applicable Idaho state sales tax and local lodging taxes on behalf of hosts.
What are the setbacks in an R-1C zone in Boise?
In an R-1C zone in Boise (standard single-family residential), the setbacks are: 20 ft front, 5 ft each side, and 20 ft rear. ADUs must maintain 5 ft side and 10 ft rear setbacks. Always verify specific parcel setbacks with Boise Planning and Development Services.
Are solar panels required on new homes in Boise?
No. Idaho does not have a solar mandate for residential construction. Solar is voluntary in Boise. Idaho Power serves the Boise area and offers net metering through their Solar PV Program. HOAs have limited ability to prohibit solar installations under Idaho Code Section 55-115.
What makes Boise zoning unique?
Boise is one of the fastest-growing cities in the US and has updated its zoning code to address rapid growth and housing demand. The city has hillside development constraints through the Hillside and Foothill Development Ordinance for properties in the foothills areas. Boise is also notable for its Greenbelt trail system along the Boise River, which creates open space requirements near the river.
Source: Boise Building Code — ADU (Accessory Dwelling Unit) Requirements. Last verified April 5, 2026. View source