How Kirkland Handles Accessory Structures: A Practical Guide

Kirkland maintains 139 local ordinances across all categories, and 4 of those deal specifically with accessory structures. Here is a breakdown of what the city actually requires, what is prohibited, and where Kirkland falls on the strict-to-permissive spectrum compared to other cities.

ADU Impact Fees

Kirkland caps the transportation impact fee on a new accessory dwelling unit at fifty percent of the fee that would apply to the principal house on the same lot. The cap, set by KMC 27.04.030(m) to comply with the state ADU statute, applies once an ADU exceeds 800 square feet, the point where the city's separate small-ADU exemption stops covering it.

Key details: ADU fee cap: 50% of principal-unit impact fee. Small-ADU exemption: 800 sq ft or less pays no fee. Deferral admin fee: $240 per building permit. Independent fee study fee: $100 per calculation. Deferral deadline: 18 months after permit issuance.

No building permit for an ADU is issued until the capped or exempted fee is paid in full, per KMC 27.04.030(h); permits placed on the deferred-payment track must have the outstanding fee, less credits, paid before final inspection, final occupancy, or eighteen months after issuance, whichever is first. Missing the deferred deadline stops final inspection and occupancy sign-off. Applicants using the deferral option owe a nonrefundable $240 administration fee regardless of when the underlying impact fee is ultimately paid.

ADU Rules

Kirkland allows up to two accessory dwelling units per single-family lot, attached or detached, each capped at 1,200 square feet, permitted through the Planning and Building Department with a recorded covenant and reduced parking near transit.

Key details: ADUs allowed per lot: 2 (one attached + one detached, or two of either). Max ADU size: 1,200 sq ft gross floor area. Parking near transit: None required within 1/2 mile of major transit stop. Parking elsewhere: 1 space if more than one ADU on lot. Permitting body: Planning and Building Department.

Building or operating an ADU without the required City permit, covenant, or inspection is a zoning code violation subject to Planning and Building Department code enforcement, which can require the unit be brought into compliance, registered, or removed; the property covenant itself runs with the land as long as the ADU exists.

Shed & Carport Rules

Kirkland caps detached accessory structures like sheds, garages and barns at 1,200 square feet, plus 10 percent of any lot area over 7,200 square feet, and limits their height under KZC 115.08. A shed stays permit-exempt under KMC 21.06.215(1)(A) only if it's 200 square feet or less, 120 for IBC structures, and no taller than 12 feet.

Key details: Max accessory floor area: 1,200 sq ft plus 10% over 7,200 sq ft lot. Height cap: Zone max or 15 ft above house roof, lower controls. Permit-exempt shed (IRC): 200 sq ft or less, 12 ft max. Permit-exempt shed (IBC): 120 sq ft or less, 12 ft max. Governing codes: KZC 115.08 and KMC 21.06.215(1)(A).

Building an oversized or permit-triggering shed without applying for a permit is an unlawful act under KMC 21.06.590, enforceable under Chapter 1.12 KMC, and exceeding KZC 115.08's floor area or height cap is a zoning code violation the Planning and Building Department can require to be corrected or removed. The building official can issue a stop work order under KMC 21.06.610 and assess an investigation fee under 21.06.620.

Garage Conversions

Converting a detached garage into an accessory dwelling unit in Kirkland is exempt from the zone's current setback and lot coverage rules under KZC 115.07(6), so long as the conversion doesn't increase any existing nonconformity. The resulting ADU is capped at 1,200 square feet of gross floor area and must meet applicable building and fire code standards.

Key details: Max ADUs per lot: 2 per single-family lot. Garage conversion: exempt from setback/lot coverage. Size cap: 1,200 sq ft gross floor area. Registration: covenant recorded with King County. Parking: waived within 0.5 mi of transit.

An ADU created or converted without the required permit, registration or recorded covenant is a code violation handled by the Planning and Building Department under KMC Chapter 1.12. The city can order corrections through a notice and order, and unresolved violations accrue civil fines of $100 to $500 per day depending on how long noncompliance continues, capped at $50,000 per violation under KMC 1.12.045.

The Bottom Line

Kirkland's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Kirkland is broadly strict or permissive.

This guide is based on Kirkland's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.