ADU Regulations

Definitions

Attached ADU (AADU)

An accessory dwelling unit that is added to or included within the primary dwelling unit on a lot.

Detached ADU (DADU)

An accessory dwelling unit located within a detached structure separate from the primary dwelling unit on a lot.

 

Regulations

Size/Scale

Maximum size of 1,200 square feet.1
Number of ADUs

Two – both may be either attached or detached.2

Applicants planning on two attached ADUs should contact the Planning and Building Department at 425-587-3600 for additional Building Code assistance.

Development Standards

Must conform to development standards, i.e. floor area ratio, lot coverage, setbacks, etc., that regulate the primary dwelling unit.3, 4

Ownership

An ADU may be segregated in ownership from the primary dwelling unit, except on properties within the Residential-L Shoreline Environment.5

Subdivision

A DADU may be placed on its own 'unit lot' through a unit lot subdivision.6

Parking

No off-street parking is required for property within one-half mile of a major transit stop.7

Outside of one-half mile of a major transit stop one off-street parking is required for the first ADU, except if on-street parking is available within 600 feet or the property is located within ½ mile of frequent transit.8

 

1 The Planning Director may approve additional square footage if an AADU is located on a single floor within the existing primary dwelling unit.

2 Any property within the Residential-L Shoreline Environment is only allowed one ADU.   

3 Except as modified by KZC 115.07.6, KZC 115.42, and KZC 115.115(3)(o). 

4 DADUs shall be located landward of the principal residence on any property located within the Residential-L and M/H Shoreline Environments pursuant to KZC 83.200.3.

5 ADUs within M/H Shoreline Environment may have separate ownership subject to a Substantial Development Permit. Any ADU created within the M/H Shoreline Environment under separate ownership will require a pedestrian pathway meeting the requirements of KZC 83.420.

6 Visit the Unit Lot Subdivision Code Amendment webpage for more information.

7 Kirkland's current Major Transit Stop is the STRIDE (I-405) bus rapid transit station. Future Major Transit Stops will include stops along King County Metro's RapidRide K Line once construction is underway.

8 Frequent transit is transit service with 15-minute headways during commute hours.

 

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