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How ADUs are Regulated in Kirkland, WA

In this article (click on hashtag to read):


Accessory Dwelling Units (ADUs) are also known as in-law units, backyard cottages, secondary units and more. More specifically, an ADU is a subordinate residence either attached or detached to a single-family home.

ADUs offer housing opportunity for our community by:

  • Increasing housing affordability

  • Creating a wider range of housing options

  • Adding housing flexibility as families grow or change

  • Adding an income stream when families need it

  • Allowing seniors to stay near their families

  • Preserving neighborhood character

ADU market neighborhood

Let's answer common ADU questions.

1.Can I build an ADU on my property?

You may be able to build up to two ADUs on your property. ADUs must meet zoning rules like setbacks, lot coverage, height, and floor area ratio. ADUs must also meet Building and Fire Codes.

2. What is my zone?

You may find your property’s zoning two ways:

  1. Kirkland’s Zoning Map: This is a citywide map that describes the zoning classifications within Kirkland.

  2. Property Search: View through a map browser your property and get information such as permit history, King County Assessor’s information, zoning information, and more. You can also get a property report that includes information important when developing your property such as:

  • Zoning

  • Property Size

  • Sewer District, Water District

  • Stream, wetland, slopes and their buffers impacting your property.

3. How do I apply for ADU permit?

Application forms, instructions, and fees are found at the City’s Single Family & Duplex Permits webpage.

All permits can be applied for through MyBuildingPermit.

4. What are useful resources for designing an ADU?

If you are considering developing an ADU here are some useful links to resources outside of the City. Some information on these websites may not be consistent with Kirkland codes. Be familiar with Kirkland's regulations before submitting for a permit.

  • A Step by Step Guide to Design Development

  • Links to videos, articles, and other web resources.

  • Information on how to select an architect and contractor

  • An overview on lending assistance.

City of Seattle’s ADUniverse provides:

  • Links to over 160 DADU designs and designers

  • A step-by-step guide for creating an ADU.

Now let's go into ADU regulations.


  • Attached ADU (AADU) - Accessory dwelling units that are added to or included within the principal unit.

  • Detached ADU (DADU) - Accessory dwelling units that are located in a detached structure.

Size/Scale: Maximum size of 1,200 square feet.

Number of ADUs: Two – both may be either attached or detached.

Location: Must conform to development standards, i.e. lot coverage, setbacks, etc., for single-family dwellings in the applicable use zone.

Owner Occupancy: Not required.

Parking: One ADU: none. Two ADUs: one required, with exceptions (available street parking within 600 feet or property is located within ½ mile of frequent transit).

Separate Ownership: Allowed.

Required yards (setbacks): Same as underlying zoning. DADUs may be located within 5 feet of an alley. DADUs without alley access may be located no closer than 5 feet from the rear property line as long as the portion of the DADU in the reduced setback is no taller than 15 feet.

Pre-Approved DADUs

The City of Kirkland offers a Pre-approved detached accessory dwelling unit (DADU) program. These plans offer a faster and cheaper way to create an accessory dwelling unit on your property. To use a pre-approved plan, a homeowner pays a royalty, set by the designer up to $1,000, for the use of their plan.

"The Family" by Ahouse Studio

If you have some more questions about ADUs, please do not hesitate to CONTACT ME.


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