Accessory Dwelling Unit (ADU) Permit in Nampa, Idaho
Required for construction of a new accessory dwelling unit on a residential property in Nampa. Nampa provides a dedicated ADU Building Permit Application & Checklist.
Verified 2026-06-29 · Source
When you need this permit
- Verify ADU is permitted in the property's zoning district with Planning & Zoning
- Submit Residential ADU Building Application & Checklist
- Plans must comply with 2018 IRC
- Trade sub-permits (electrical, plumbing, mechanical) required separately
Required documents
- Req
Residential ADU Building Application & Checklist (Oct 2024)
Nampa's dedicated ADU permit application and checklist; available at cityofnampa.us/DocumentCenter/View/18798
- Req
Construction Drawings
Full construction drawings including site plan, floor plans, elevations, and structural details
- Req
Energy Code Compliance Documentation
Rescheck or equivalent demonstrating 2018 IECC compliance for the ADU
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| ADU Building Permit — valuation-based per Exhibit A | Per Nampa Exhibit A valuation table; plan review is 65% of permit fee | Nampa Exhibit A Schedule of Permit Fees (Dec 2021) |
| Reinspection (after first reinspection for same item) | $55.00 flat fee | — |
Review timeline
15–15 business days
Nampa’s published plan-review target
Inspection process
- 1
Foundation / Footings
Before concrete pour — verify depth (24-inch frost line for full foundations), forms, rebar
- 2
Framing
Structural framing, egress windows, fire separation before walls covered
- 3
MEP Rough-In
Mechanical, electrical, and plumbing rough-ins under separate trade permits
- 4
Final
All work complete, smoke/CO detectors, address posted; Certificate of Occupancy issued
Tips
- Nampa's plan review target for ADUs is 15 working days per the published Plan Review Processing Time Frames (Aug 2024) — same as new residential.
- Confirm ADU zoning eligibility with Planning & Zoning at (208) 468-4430 before spending resources on design.
- Trade sub-permits (electrical, plumbing, mechanical) are required separately for ADU construction.
Frequently asked questions
- Can I build an ADU on my property in Nampa?
- ADUs are allowed on qualifying residential properties in Nampa. You must first confirm your zoning district allows an ADU with Planning & Zoning at (208) 468-4430, then apply using the Residential ADU Building Application & Checklist through the CSS online portal.
Sources & verification
Verified against official sources. Last reviewed 2026-06-29.
- Nampa Building Safety & Code Department — official building department
- Residential ADU Building Application & Checklist (Oct 2024)
- Plan Review Processing Time Frames (Aug 14, 2024)
- Building Permit Process | City of Nampa
Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Nampa building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.
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