Kirkland vs. Redmond ADU rules
Redmond builds taller, Kirkland builds bigger. Redmond exempts structures containing ADUs from its usual 22-ft accessory cap, letting a detached ADU rise to the zone maximum — 38 ft in Neighborhood Residential (RZC 21.04.1120.C.1) — while Kirkland holds DADUs to the zone's single-family height, 25–30 ft, and just 15 ft if sited in the reduced 5-ft rear setback. Kirkland's tradeoff is size: 1,200 sq ft per ADU against Redmond's 1,000 sq ft, which is exactly the state-law floor. Redmond also explicitly permits tiny homes on wheels as an ADU type (max 400 sq ft), an option Kirkland's code doesn't address. Both cities require zero parking for a single ADU.
✓ Verified against code · August 19, 2026
Kirkland rules run under KZC 115.07 (Kirkland Zoning Code), adopted by Ordinances O-4905 / O-4913, in effect since June 1, 2025.
✓ Verified against code · August 19, 2026
Redmond rules run under RZC 21.04.1110 (Redmond Zoning Code, post-Redmond 2050 restructure), adopted by Ordinance 3220 (recodification); Ord 3261 pending codification, in effect since June 28, 2025.
Rule by rule
| Rule | Kirkland | Redmond |
|---|---|---|
| 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) | Two ADUs or tiny homes per residential lot — attached (within or added to the primary home) or detached, in any mix.RZC 21.04.1110.C.1, C.2.a |
| 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) | 1,000 sq ft total (the state-law floor, exactly). The Administrator may allow more if the ADU occupies an entire single floor of the primary unit, or on lots over 10,000 sq ft where the ADU is affordable or provides a public benefit. Tiny homes max 400 sq ft.RZC 21.04.1110.C.3.a–d |
| 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) | Structures containing ADUs may go to the underlying zone maximum — 38 ft base in Neighborhood Residential — rather than the 22-ft cap that applies to other accessory structures.RZC 21.04.1120.C.1; Table 21.08.200.B |
| 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) | Zone setbacks apply (NR: front 10 ft, street side 10 ft, interior side 3 ft, rear 5 ft, alley 2 ft) — and a detached ADU may sit immediately on a lot line that abuts a public alley or right-of-way. No accessory structures in the front setback.Table 21.08.300.A; RZC 21.04.1120.C.4–5 |
| 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) | Zero. The parking table sets ADU minimums at 0 in all three location categories — near transit, in centers, and everywhere else. No transit-proximity condition needed.RZC 21.40.010 Table D |
| 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) | None. No owner-occupancy provision exists anywhere in the current chapter.RZC 21.04.1110 (absence verified) |
| 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 | The DADU and the primary unit must each meet zone lot coverage (NR 50%; 60% for lots ≤18,000 sq ft with 3+ units). NR also caps total gross floor area of all structures by unit count — 4,500 sq ft for one unit, 6,000 for two, 7,500 for three — which effectively binds the combined house-plus-ADU size.Table 21.08.200.B–.C; RZC 21.04.1120.C.2.a |
| 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) | Permitted outright in NR, NMF, NMU and mixed-use zones — a residential building permit only, no land-use permit. No city-published ADU timeline; secondary sources suggest roughly 4–8 weeks.RZC 21.04.0100; redmond.gov/469 |
Kirkland: 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.
Redmond: worth knowing
- Redmond is a rare explicit-yes city for tiny homes on wheels: they count as an ADU type (max 400 sq ft), with the trailer base landscape-screened if visible from public view.
- Fire sprinklers are required for new detached ADUs.
- A home business inside a detached ADU has no size restriction — unusual.
- The NR total-floor-area schedule (6,000 sq ft at two units) can bind before lot coverage does on large-house lots.
Redmond: on our watchlist
Ordinance 3261 (adopted June 2, 2026) — the 2025 Legislative Conformance package — amends RZC 21.04.1110/21.04.1125 (parking, permitting timelines, conversions) and is pending codification. We re-check each pass and will log the changes the day they publish.
Full detail: Kirkland · Redmond · back to the Washington hub. 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.