ADU Ledger

Do I need to add parking for an ADU in Seattle?

✓ Verified against code · August 19, 2026

No. Seattle requires no off-street parking for ADUs anywhere in the city, regardless of transit proximity.

Citation: SMC 23.42.022.I

How current is this?

Seattle’s ADU rules run under SMC 23.42.022 and the new Chapter 23.44 (Neighborhood Residential) (Ordinance 127376 (CB 120993)). Seattle rewrote its residential zoning twice in eight months: the HB 1337 compliance package (Ord 127211, May 2025), then the permanent state-compliance code signed December 22, 2025 and effective January 21, 2026, which repealed the old Chapter 23.44 and amended SMC 23.42.022. Most guides written in 2025 describe interim rules that no longer exist. We verified this answer against primary sources on August 19, 2026, and every change we catch is logged in the changelog.

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Not legal advice — lot-specific overlays can change the answer for your parcel. The citation above points at the governing code section; check it, or ask the city to confirm.