Kootenai County, ID Accessory Structures: ADU Rules (2026)
ADU rules in Kootenai County, ID, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Units allowed
- One ALU per parcel
- Size cap
- 1,000 sq ft or 50% of primary
- Common wall
- Not permitted
- Permit
- Accessory living unit permit required
- Setbacks
- Accessory-building setbacks of the zone
Summary
Unincorporated Kootenai County allows one accessory living unit per parcel with an accessory living unit permit from the Director. It cannot share a common wall with the main home and is capped at 1,000 sq ft or 50% of the primary home's habitable space.
The square footage of the accessory living unit shall not exceed 1,000 square feet of habitable space or fifty percent (50%) of the habitable space of the primary structure, whichever is greater. ... An accessory living unit cannot share a common wall with the principal dwelling unit.
Official source re-checked September 8, 2026: the cited page had not changed since it was quoted.
Full Breakdown
Under Kootenai County Land Use and Development Code 8.4.301, an accessory living unit is a secondary dwelling with independent living, cooking, sanitation, and sleeping facilities on the same parcel as the principal dwelling. It cannot share a common wall with the primary home. Size is capped at 1,000 sq ft of habitable space or 50% of the primary structure's habitable space, whichever is greater. Only one ALU is allowed per parcel, and it must meet the accessory-building setbacks of the underlying zone. An ALU permit from the Director is required. Idaho cities (Coeur d'Alene, Post Falls, Hayden) set their own ADU rules.
Violations & Fines
Establishing an ALU without the required permit is a land-use code violation subject to enforcement under Chapter 8, Article 8.6 of the code.
Frequently Asked Questions
Can I share a wall between my ADU and house?
How big can my ADU be?
Sources & Official References
Other rules in Kootenai County
How Kootenai County compares: Easiest Cities to Build an ADU·Compare Kootenai County to another location·View the Idaho accessory structures overview
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