Kirkland ADU rules

✓ Verified against code · August 19, 2026

Current rules under KZC 115.07 (Kirkland Zoning Code), adopted by Ordinances O-4905 / O-4913, in effect since June 1, 2025. Kirkland's 2025 middle-housing and state-conformance ordinances (O-4905, O-4913) updated KZC 115.07. Kirkland pairs its rules with the most homeowner-friendly tooling in the region: a full ADU Toolkit microsite and an active pre-approved DADU plan gallery.

Common questions, answered from the code

How big can a Kirkland ADU be?

1,200 sq ft of gross floor area — with meaningful exclusions: sub-5-ft-ceiling space, uncovered decks and patios, and up to 200 sq ft of exterior elements don't count. National guides quoting 1,000 sq ft are citing the state floor, not Kirkland's adopted limit.

KZC 115.07(4) · Permalink

Does a Kirkland DADU count against floor-area limits?

Partially — and this is a Kirkland-specific advantage: the first 500 sq ft (lots under 8,500 sq ft) or 800 sq ft (larger lots) of a DADU behind the main structure is excluded from FAR.

KZC 115.42(1)(c)–(d) · Permalink

Do I need parking for a Kirkland ADU?

Usually not. Nothing within a half mile of a major transit stop; elsewhere, only a second ADU triggers one space, and even that is waived with nearby on-street parking or frequent transit.

KZC 115.07(7) · Permalink

Can I use a pre-approved DADU plan in Kirkland?

Yes — Kirkland runs an active gallery of city-vetted DADU plans. You pay the designer a royalty (capped at $1,000) and get a permit-ready plan with expedited review and a reduced submittal list.

Kirkland ADU Toolkit / Pre-Approved DADU Program · Permalink

Can a Kirkland ADU be sold separately?

Yes — the code allows ADUs to be segregated in ownership, and non-stacked ADUs may be subdivided via unit-lot subdivision under KMC Title 22.

KZC 115.07(2)–(3) · Permalink

The rules at a glance

ADUs allowed per lot	Two ADUs per single-family dwelling — one attached plus one detached, or two of either type. ADUs don't count as 'dwelling units' for one-unit-per-lot limits.KZC 115.07 (introductory)
Maximum size	1,200 sq ft of gross floor area per ADU. Excluded: floor area under 5-ft ceilings, uncovered rooftop decks and at-grade patios, and up to 200 sq ft of exterior elements. The Planning Director may allow a larger attached ADU occupying an entire existing floor.KZC 115.07(4)(a)–(c)
Detached ADU height	The zone's single-family height applies: 25 ft above average building elevation in RS/PLA 3C/PLA 6E, 30 ft in RSX/RSA/PLA 16. A DADU sited within the reduced 5-ft rear yard is capped at 15 ft.KZC 115.07(5); 15.30.060; 115.115(3)(o)(3)
Detached ADU setbacks	Zone single-family setbacks apply (RS: front 20 ft, sides 5 ft each, rear 10 ft). A DADU without alley access may come within 5 ft of the rear line (with the 15-ft height cap), and may extend to the rear lot line where it abuts an alley. Conversions of existing structures are exempt from setbacks and coverage if the nonconformity isn't increased.KZC 115.07(5)–(6); 115.115(3)(o)(3)–(4)
Off-street parking	None within a half mile of a major transit stop. Beyond that, one space is required only when there's more than one ADU — and even that is waived if on-street parking exists within 600 ft or frequent transit is within a half mile. The first ADU never requires parking.KZC 115.07(7)(a)–(b)
Owner-occupancy	None. The code affirmatively allows the ADU to be segregated in ownership from the house, and ADUs (except stacked ones) may be subdivided via unit-lot subdivision.KZC 115.07(2)–(3)
Lot coverage / floor area	Zone lot coverage applies (50% in RS/RSA). FAR applies per zone, but the first 500 sq ft (lots under 8,500 sq ft) or 800 sq ft (8,500+ sq ft) of a DADU located behind the main structure is excluded from FAR — a real design lever.KZC 115.42(1)(c)–(d); 15.30.060
Permit path & timeline	Permitted outright. Requires an ADU permit with owner affidavit, a registration covenant recorded with King County, and a standard building permit (via MyBuildingPermit.com). Expedited review is available; pre-approved plans use a reduced submittal list. No published timeline — secondary sources suggest 8–12 weeks standard.KZC 115.07(9)

Worth knowing

The pre-approved DADU plan gallery is real and active (designs by Cast Architecture, Fivedot, Ahouse Studio and others) — the homeowner pays a designer royalty capped at $1,000 and gets a permit-ready plan plus expedited review.
Kirkland kept a covenant-recording step most cities dropped — one extra piece of paperwork at King County.
The 500/800 sq ft FAR exclusion rewards siting the DADU behind the main house.
The 'Kirkland ADU Toolkit' microsite is the best official homeowner resource in the region.

Check your parcel

The rules above are citywide — what you can build depends on your lot’s zone, size, and setbacks. Look yours up on the official viewers:

Primary sources

Other Washington cities

Bellevue · Bothell · Burien · Edmonds · Everett · Issaquah · Kent · Lynnwood · Olympia · Redmond · Renton · Sammamish · Seattle · Shoreline · Tacoma

Not legal advice. Every fact above cites the code section it comes from — check the cite, or ask your city’s planning department to confirm your specific lot. Spotted an error or a new ordinance? See about to reach us; corrections are logged in the changelog.