Yakima, WA Accessory Structures: ADU Rules (2026)
ADU rules in Yakima, WA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Floor area cap
- 1,000 sq ft
- Code text allows
- one ADU per lot
- State law (HB 1337)
- requires two ADUs allowed
- Required
- recorded deed restriction
- Parking
- per YMC Ch. 15.06
Summary
Yakima allows one accessory dwelling unit per single-family lot as a permitted use, capped at 1,000 square feet, with matching setbacks, required parking, and a recorded deed restriction, though 2023 state law now overrides the one-ADU cap.
An accessory dwelling unit is a permitted use on all parcels containing a single-family dwelling (See YMC § 15.04.030, Table 4-1, for level of review) subject to all of the following conditions:
1. The accessory dwelling unit may be attached to the primary residence or attached to or above a detached garage, or be its own stand-alone structure.
2. Off-street parking shall be provided as required in YMC Chapter 15.06 for both the ADU and the primary residence located on the lot they are intended to serve.
3. The ADU’s floor area shall not exceed one thousand square feet.
4. The ADU’s exterior walls shall be designed so as to be similar in style, color, and building materials to the primary detached dwelling.
5. An ADU attached to the primary structure shall have the same building setbacks as the primary structure. An ADU that is attached to, or built above, a detached garage or a stand-alone structure shall have the same building setbacks as an accessory structure.
6. A parcel/lot shall contain no more than one single-family residence and one ADU.
7. ADUs shall not be allowed on parcels containing a duplex or multifamily dwelling, or a commercial or industrial structure/use.
8. The primary residence and the ADU shall both be connected to public sewer and water if available (within two hundred feet).
a. If the ADU is attached to the primary dwelling unit, the two dwelling units shall share a single sewer and water connection.
b.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4980636; v1 updated 2026-08-03; through 08-03-2026).
Full Breakdown
Under YMC § 15.09.045, an ADU is a permitted use on any parcel with a single-family dwelling, reviewed per the level set in YMC § 15.04.030, Table 4-1. Conditions include a 1,000-square-foot floor-area cap, exterior materials matching the primary home, off-street parking for both units, sewer/water connection, and a deed restriction recorded with the Yakima County auditor. The code still says only one ADU per lot, but Washington's 2023 HB 1337 requires GMA cities to permit two ADUs on most single-family lots and bars several of the old restrictions, so the two-unit floor now controls over this older one-ADU text.
Violations & Fines
The city may inspect an ADU with reasonable notice and can withdraw occupancy approval for violations of the § 15.09.045(B) conditions, forcing the owner to merge the unit into the main dwelling or convert it to an approved accessory use.
Frequently Asked Questions
Can I build two ADUs on one Yakima lot?
How big can a Yakima ADU be?
Sources & Official References
Other rules in Yakima
How Yakima compares: Easiest Cities to Build an ADU·Compare Yakima to another location·View the Washington accessory structures overview
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