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ADU Rules in Kirkland, Washington

Complete guide to building an Accessory Dwelling Unit in Kirkland — zoning, setbacks, permits, costs, and more.

Max Size: 1,200 sq ft of gross floor area (KZC 115.07(4)), above the 1,000 sq ft floor in RCW 36.70A.681(1)(f). Not counted: area under 5 ft of ceiling, uncovered rooftop decks or at-grade patios, and up to 200 sq ft of other exterior elements. Ordinance 4905 took ADUs out of the KZC 115.08 accessory-structure cap. Floor area ratio still bites: only the first 500 sq ft (lot under 8,500 sq ft) or 800 sq ft (8,500 sq ft and up) of a detached ADU behind the house is exempt from F.A.R. (KZC 115.42(1)(c)-(d)). Setbacks: 10 ft, the house standard (KZC 15.30.060), relaxed by KZC 115.115(3)(o): a detached ADU without alley access may sit 5 ft from the rear line if the part inside the required rear yard is no taller than 15 ft above ABE and the rear yard does not abut an access easement treated as a rear line; a detached ADU may extend to a rear line abutting an alley if its eaves stay on the lot and sight distance (KZC 115.135) is met (RCW 36.70A.681(1)(i)). A converted garage keeps its setbacks (KZC 115.07(6)). Parking: Varies Verified: 2026-09-20

Researched by ADU Zoning Hub · verified 2026-09-20 against Kirkland planning code and Washington ADU law · methodology · 28 sources cited ↓

ADU Score: 9/10
Very ADU-friendly · how we score

Are ADUs allowed in Kirkland, WA? [1][2][3][4][5][6][7][8][9]

Yes. Kirkland allows ADUs on most residential lots. A detached unit can be up to 1,200 sq ft, set 10 ft back from the rear line. Parking varies by lot and unit size. Owner-occupancy is not required, so the unit can be rented out. A building permit is required and applications are reviewed through the standard permit process.

Maximum size1,200 sq ft of gross floor area (KZC 115.07(4)), above the 1,000 sq ft floor in RCW 36.70A.681(1)(f). Not counted: area under 5 ft of ceiling, uncovered rooftop decks or at-grade patios, and up to 200 sq ft of other exterior elements. Ordinance 4905 took ADUs out of the KZC 115.08 accessory-structure cap. Floor area ratio still bites: only the first 500 sq ft (lot under 8,500 sq ft) or 800 sq ft (8,500 sq ft and up) of a detached ADU behind the house is exempt from F.A.R. (KZC 115.42(1)(c)-(d)).
SetbacksRear 10 ft, the house standard (KZC 15.30.060), relaxed by KZC 115.115(3)(o): a detached ADU without alley access may sit 5 ft from the rear line if the part inside the required rear yard is no taller than 15 ft above ABE and the rear yard does not abut an access easement treated as a rear line; a detached ADU may extend to a rear line abutting an alley if its eaves stay on the lot and sight distance (KZC 115.135) is met (RCW 36.70A.681(1)(i)). A converted garage keeps its setbacks (KZC 115.07(6)). · Side Same as the house: 5 ft in the RS zones, with the two side yards totalling at least 15 ft (KZC 15.30.060, DD-9); a flat 5 ft in RSX and RSA. A detached ADU closer than 10 ft to another dwelling needs a fire-rated wall (City pre-approved DADU guide). State law bars ADU setbacks stricter than the principal unit's (RCW 36.70A.681(1)(h)).
ParkingNone. Ordinance O-4948 (passed Sept. 15, 2026, effective Sept. 26, 2026) rewrites KZC 115.07(7): ADUs are exempt from any minimum vehicle parking requirement, citywide, implementing SB 5184 (RCW 35A.21.445, no parking minimums for homes under 1,200 sq ft). Until then the rule was none within a half mile of a major transit stop (the STRIDE I-405 station) and one space only for a second ADU elsewhere; the city's ADU Regulations page still shows that older text, so cite O-4948 if asked for a space.
Owner-occupancyNot required; RCW 36.70A.681(1)(b) forbids it. An ADU may be segregated in ownership from the house (KZC 115.07(2)) and, except stacked units, placed on its own unit lot through a unit lot subdivision under KMC Title 22 (KZC 115.07(3); Ordinance 4907, June 2025). Exceptions: no separate ownership in the Residential-L shoreline environment; in the M/H shoreline environment it needs a Substantial Development Permit and a pedestrian pathway under KZC 83.420 (City ADU Regulations page).

Do I need a permit to build an ADU in Kirkland? [10][11][12][13][14][15][16][17][18]

Yes. Every ADU in Kirkland needs a building permit. Review process: Apply through MyBuildingPermit.com (Kirkland > Building > New Construction; a pre-approved plan has its own scope line). The building permit carries the ADU Registration Application, an owner affidavit under KZC 115.07(9), a site plan, the Supplemental Building Information Form, a plumbing worksheet, a survey in most cases and a geotechnical report on soft, landslide or seismic soils. The registration covenant is recorded with the King County Recorder; the recording fee is added to the permit and paid before the certificate of occupancy. A separate Planning Official ADU decision ($634 in 2026) is not needed when the ADU is reviewed with the building permit. Fire checks fire flow, hydrant distance and access on every application; Public Works handles utility connections and drainage. State law bars street improvements as a permit condition (RCW 36.70A.681(1)(l))..

Permit fees2026 building permit on valuation (KMC Table 3: $1,620 plus $8.22 per $1,000 over $100,000), plan review at 65% of it, a $101 + $0.01/sq ft energy-code fee and a 3.5% technology fee: about $5,700 on a $300,000 detached ADU before plumbing, fire and utility charges. Plan licence up to $1,000.
Typical timelineAbout 3 months for a standard ADU permit, plus design and construction time (City Planning Your ADU page, 2026). A registered pre-approved DADU that qualifies for expedited review can be approved in as little as a few weeks; shoreline, geohazard and critical-area sites do not qualify.
Official Kirkland links:

Three things to know before you build in Kirkland

  • Size to 800 sq ft if the impact fee matters: since July 1, 2026 an ADU of 800 sq ft or less pays no park, transportation or fire impact fee, while an 801 sq ft unit pays about $4,189 and a 1,200 sq ft unit about $6,276 on the July-December 2026 schedule
  • Parking is off the table from Sept. 26, 2026 under Ordinance O-4948; if your site plan still shows a required space, cite KZC 115.07(7) as amended. Before that date the half-mile STRIDE (I-405) transit radius was the test
  • Convert before you build where you can: KZC 115.07(6) exempts a permitted conversion of an existing structure, detached garages included, from current setback and lot coverage requirements, provided you do not make an existing nonconformity worse

Last verified 2026-09-20 against Kirkland planning code. How we verify

Yes: Kirkland allows two ADUs on every single-family lot, each up to 1,200 sq ft of gross floor area, with no owner-occupancy requirement and, from September 26, 2026, no parking requirement anywhere in the city (Kirkland Zoning Code 115.07, as amended by Ordinances 4905, 4913 and 4948). A detached unit takes the same 20-ft front and 5-ft side yards as the house and may sit 5 ft from the rear line, or on the line where the lot backs an alley (KZC 115.115(3)(o)); an existing garage may be converted even if it breaks today's setbacks. Expect roughly three months for a standard permit, or a few weeks with one of the city's four pre-approved detached plans, and budget about $5,700 in 2026 building fees on a $300,000 project. Two things changed in 2026: ADUs larger than 800 sq ft now pay park, transportation and fire impact fees (about $6,300 for a 1,200 sq ft unit since July 1, 2026), and lots with mapped critical areas or buffers fall outside the state protections in RCW 36.70A.681.

In Kirkland you will also hear an ADU called a DADU — short for detached accessory dwelling unit, the usual term across Washington. The rules on this page apply either way.

Outside city limits? If your property is in unincorporated King County (not within Kirkland's boundaries), different rules apply — see our King County (unincorporated) ADU rules.

Zoning & Size Requirements [1][2][3][4][5][6][7][8][9]

Yes — Kirkland allows ADUs. A detached ADU can typically be up to 1,200 sq ft under current Washington and Kirkland zoning rules.

See what this means for your lot — ask Kirkland ADU builders for a quote →

Allowed ZonesAccessory use wherever a Detached Dwelling Unit is permitted in the low density zones RS, RSX, RSA, PLA 3C, PLA 6E and PLA 16 (KZC 15.20.060, Special Regulation PU-23). The WD II waterfront row does not carry PU-23, and PU-21 limits RSA 4 lots in the Goat Hill Overlay to one attached ADU. Middle-housing sites may add two attached ADUs (Chapter 113 KZC). Residential-L shoreline lots get one ADU; lots with designated critical areas or buffers lose the state floor (RCW 36.70A.681(4)).
Max Size (Detached)1,200 sq ft of gross floor area (KZC 115.07(4)), above the 1,000 sq ft floor in RCW 36.70A.681(1)(f). Not counted: area under 5 ft of ceiling, uncovered rooftop decks or at-grade patios, and up to 200 sq ft of other exterior elements. Ordinance 4905 took ADUs out of the KZC 115.08 accessory-structure cap. Floor area ratio still bites: only the first 500 sq ft (lot under 8,500 sq ft) or 800 sq ft (8,500 sq ft and up) of a detached ADU behind the house is exempt from F.A.R. (KZC 115.42(1)(c)-(d)).
Max Size (Attached)Same 1,200 sq ft gross floor area cap. Where the attached ADU sits entirely within existing gross floor area on a single floor, the Planning and Building Director may allow more so the whole floor is used (KZC 115.07(4)). Space that was legally built as habitable space need not meet current IBC ceiling heights when converted (KZC 115.07(8)).
Max Size (JADU)Not a category in Washington; Kirkland's code has no junior ADU. The nearest equivalent is an attached ADU carved out of the existing house, which under KZC 115.07(6) may reuse an existing structure even if it violates current setbacks or lot coverage, so long as the nonconformity is not made worse.
Max HeightThe single-family limit of your zone (KZC 115.07(5)): 25 ft above average building elevation in RS, PLA 3C and PLA 6E; 30 ft in RSX, RSA and PLA 16 (KZC 15.30.060). Ordinance 4905 removed ADUs from KZC 115.08, so the old accessory-structure cap of 15 ft above the house no longer applies. If you use the 5-ft rear setback, the part of the structure inside the required rear yard may be no taller than 15 ft above ABE (KZC 115.115(3)(o)(3)). State floor: 24 ft (RCW 36.70A.681(1)(g)).
Max UnitsTwo ADUs per single-family dwelling: one attached and one detached, or two of either type (KZC 115.07). The section says an ADU shall not be considered a dwelling unit for the one-house-per-lot rules in Chapters 15 through 56 KZC, matching RCW 36.70A.681(1)(c). Middle-housing projects may also include up to two attached ADUs (Chapter 113 KZC). Residential-L shoreline properties are limited to one ADU, and Goat Hill RSA 4 lots to one attached ADU (PU-21).

Setback Requirements [1][2][3][4][5][6][7][8][9]

Kirkland requires a rear setback of about 10 ft for a detached ADU, and parking requirements vary by unit size or location. Owner-occupancy is not required — you can rent it out without living on the property.

Rear Setback10 ft, the house standard (KZC 15.30.060), relaxed by KZC 115.115(3)(o): a detached ADU without alley access may sit 5 ft from the rear line if the part inside the required rear yard is no taller than 15 ft above ABE and the rear yard does not abut an access easement treated as a rear line; a detached ADU may extend to a rear line abutting an alley if its eaves stay on the lot and sight distance (KZC 115.135) is met (RCW 36.70A.681(1)(i)). A converted garage keeps its setbacks (KZC 115.07(6)).
Side SetbackSame as the house: 5 ft in the RS zones, with the two side yards totalling at least 15 ft (KZC 15.30.060, DD-9); a flat 5 ft in RSX and RSA. A detached ADU closer than 10 ft to another dwelling needs a fire-rated wall (City pre-approved DADU guide). State law bars ADU setbacks stricter than the principal unit's (RCW 36.70A.681(1)(h)).
Front Setback20 ft, the same front yard as the house, in RS, RSX, RSA, PLA 3C, PLA 6E and PLA 16 (KZC 15.30.060). On a corner lot only one front yard must be 20 ft; the other is treated as a side yard of 5 ft (DD-15) or, where the two fronts are essentially parallel, as a rear yard of 10 ft (DD-16).
Parking RequiredNone. Ordinance O-4948 (passed Sept. 15, 2026, effective Sept. 26, 2026) rewrites KZC 115.07(7): ADUs are exempt from any minimum vehicle parking requirement, citywide, implementing SB 5184 (RCW 35A.21.445, no parking minimums for homes under 1,200 sq ft). Until then the rule was none within a half mile of a major transit stop (the STRIDE I-405 station) and one space only for a second ADU elsewhere; the city's ADU Regulations page still shows that older text, so cite O-4948 if asked for a space.
Owner OccupancyNot required; RCW 36.70A.681(1)(b) forbids it. An ADU may be segregated in ownership from the house (KZC 115.07(2)) and, except stacked units, placed on its own unit lot through a unit lot subdivision under KMC Title 22 (KZC 115.07(3); Ordinance 4907, June 2025). Exceptions: no separate ownership in the Residential-L shoreline environment; in the M/H shoreline environment it needs a Substantial Development Permit and a pedestrian pathway under KZC 83.420 (City ADU Regulations page).
Min Lot SizeNo ADU-specific minimum: any lot that can hold a house can hold two ADUs (RCW 36.70A.681(1)(e); KZC 115.07 sets none). District minimums for the lot itself run from 3,800 sq ft in RSA 8 and 5,000 sq ft in RS 5.0 and RSX 5.0 to 35,000 sq ft in RS 35 and RSX 35 (KZC 15.30.060, DD-7 and DD-11). Floor area ratio, not lot size, is what usually squeezes a detached ADU on lots under 8,500 sq ft (KZC 115.42).

Permit Process & Fees [10][11][12][13][14][15][16][17][18]

An ADU permit in Kirkland goes through a standard permit review. Typical timeline: About 3 months for a standard ADU permit, plus design and construction time (City Planning Your ADU page, 2026). A registered pre-approved DADU that qualifies for expedited review can be approved in as little as a few weeks; shoreline, geohazard and critical-area sites do not qualify. Permit fees: 2026 building permit on valuation (KMC Table 3: $1,620 plus $8.22 per $1,000 over $100,000), plan review at 65% of it, a $101 + $0.01/sq ft energy-code fee and a 3.5% technology fee: about $5,700 on a $300,000 detached ADU before plumbing, fire and utility charges. Plan licence up to $1,000.

Approval ProcessApply through MyBuildingPermit.com (Kirkland > Building > New Construction; a pre-approved plan has its own scope line). The building permit carries the ADU Registration Application, an owner affidavit under KZC 115.07(9), a site plan, the Supplemental Building Information Form, a plumbing worksheet, a survey in most cases and a geotechnical report on soft, landslide or seismic soils. The registration covenant is recorded with the King County Recorder; the recording fee is added to the permit and paid before the certificate of occupancy. A separate Planning Official ADU decision ($634 in 2026) is not needed when the ADU is reviewed with the building permit. Fire checks fire flow, hydrant distance and access on every application; Public Works handles utility connections and drainage. State law bars street improvements as a permit condition (RCW 36.70A.681(1)(l)).
Review TimelineAbout 3 months for a standard ADU permit, plus design and construction time (City Planning Your ADU page, 2026). A registered pre-approved DADU that qualifies for expedited review can be approved in as little as a few weeks; shoreline, geohazard and critical-area sites do not qualify.
Permit Fees2026 building permit on valuation (KMC Table 3: $1,620 plus $8.22 per $1,000 over $100,000), plan review at 65% of it, a $101 + $0.01/sq ft energy-code fee and a 3.5% technology fee: about $5,700 on a $300,000 detached ADU before plumbing, fire and utility charges. Plan licence up to $1,000.
Impact FeesCharged since July 1, 2026 on ADUs larger than 800 sq ft (Ordinances O-4901 and O-4904, phased in): park $2.59, transportation $2.26 and fire $0.38 per sq ft of the whole unit. The city's own example is $4,189 for an 801 sq ft ADU; a 1,200 sq ft unit pays about $6,276. ADUs of 800 sq ft or less pay nothing, and there is no school impact fee on an ADU (O-4910). Rates step up again on Jan. 1 and July 1, 2027; RCW 36.70A.681(1)(a) caps ADU impact fees at half the single-family rate, which is where the current rates sit.
Plan CheckStandard building plan review; intake covers the first review and one resubmittal, and each further review is billed at $179 an hour. The portion of a house converted to an ADU must meet current health and safety codes except that legally built habitable space need not meet IBC ceiling heights (KZC 115.07(8)). An ADU created without a finaled building permit needs an ADU inspection before a permit issues (KZC 115.07(9)(a)(3)). A detached unit closer than 10 ft to another dwelling needs a fire-rated wall detail, and fire sprinklers may be required after the Fire Department's fire-flow and access check.
Pre-Approved PlansYes. The city's Pre-Approved Detached ADU Plans gallery lists four registered plan families from three local design firms, from a 476-636 sq ft one- or two-bedroom cottage to 1,000-1,132 sq ft two- and three-bedroom units, including a single-level no-stairs layout and mirrored versions. You license the plan from its designer (up to $1,000), staff attach the registered set to your permit so you submit no construction drawings, and a qualifying site gets expedited review. Custom plans remain allowed.

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Construction Costs [19][20][21][22]

Building an ADU in Kirkland typically costs $325,000-$550,000 ($400-$650 per sq ft); a garage conversion runs $100,000-$225,000.

See what this means for your lot — ask Kirkland ADU builders for a quote →

Average Build Cost$325,000-$550,000
Cost per Sq Ft$400-$650
Garage Conversion$100,000-$225,000
Prefab ADU (Installed)$300,000-$450,000

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Rental Income Potential [23][24][25][26]

A 2-bedroom ADU in Kirkland rents for around $2,850-$3,350/mo, an estimated 6-9% gross rental yield on a $350,000-$550,000 detached build renting at $2,500-$3,300/mo, before vacancy, taxes, the new impact fee and financing; a conversion of existing space at $100,000-$225,000 yields roughly twice.

Avg Rent (1 Bedroom)$2,450-$2,850/mo
Avg Rent (2 Bedroom)$2,850-$3,350/mo
Short-Term RentalYes, with a Washington state and a City of Kirkland business licence, and the city's short-term rental page answers the ADU question directly: a registered detached ADU may be rented short-term (under 30 days) without li.
Est. Annual ROI6-9% gross rental yield on a $350,000-$550,000 detached build renting at $2,500-$3,300/mo, before vacancy, taxes, the new impact fee and financing; a conversion of existing space at $100,000-$225,000 yields roughly twice.

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Recent Law Changes

What's Changed Recently

  • Ordinance O-4948 (passed Sept. 15, 2026; published Sept. 21, 2026; effective Sept. 26, 2026) rewrote KZC 115.07(7): accessory dwelling units are exempt from the requirement to provide a minimum number of vehicle parking spaces anywhere in Kirkland, replacing the half-mile-from-transit rule. It implements SB 5184 (RCW 35A.21.445), which bars parking minimums for homes under 1,200 sq ft
  • Impact fees reached ADUs on July 1, 2026: complete permit applications on or after that date for an ADU over 800 sq ft pay park ($2.59/sq ft), transportation ($2.26/sq ft) and fire ($0.38/sq ft) impact fees on the whole unit under Ordinances O-4901 and O-4904, phased in with further steps on Jan. 1 and July 1, 2027; ADUs of 800 sq ft or less stay exempt and the school impact fee (O-4910) does not apply to ADUs
  • Development Services fees rose 2.7% (CPI-W) on Jan. 1, 2026: building permits on the KMC Table 3 valuation scale, plan review at 65%, hourly reviews $179, and a $634 Planning Official ADU decision fee that is waived when the ADU is reviewed with a building permit
  • Ordinance O-4938 (June 16, 2026) added a new KMC Chapter 22.10 to enable residential lot splitting, alongside the unit lot subdivision rules Ordinance O-4907 created in June 2025; KZC 115.07(3) lets one or more ADUs, other than stacked units, be subdivided within a unit lot subdivision
  • Ordinance O-4905 (adopted June 17, 2025, published June 27, effective July 2, 2025) rewrote KZC 115.07 for HB 1337 and HB 1110: no size limit on a second ADU, no location or entrance rules, conversions of existing structures exempt from setbacks and lot coverage, ADUs removed from the KZC 115.08 accessory-structure size and height caps, and the F.A.R. distance-between-structures test dropped from KZC 115.42. Ordinance O-4913 (Sept. 16, 2025) made further amendments to Chapter 115
  • Ordinance O-4918 (Dec. 9, 2025) updated Kirkland's Critical Areas Ordinance (KZC Chapters 85, 90 and 95); lots designated with critical areas or their buffers are outside the protections of RCW 36.70A.681 (subsection (4)), so a mapped stream, wetland or steep-slope buffer is the most common reason a Kirkland lot gets less than the statute promises
  • Washington HB 1337 (2023 c 334), codified at RCW 36.70A.681 and unchanged as of September 2026, sets the floor: two ADUs on every lot in an urban-growth-area zone that allows single-family homes, no owner occupancy, no size cap under 1,000 sq ft, no roof-height limit under 24 ft, no stricter setbacks than the house, garage conversions allowed, alley lot-line siting, impact fees capped at 50% of the principal unit, no street improvements, and no parking within a half mile of major transit. EHB 1345 (2026, effective June 11, 2026) only reaches county land outside urban growth areas and does not touch Kirkland

Tips for Building an ADU in Kirkland

  • Size to 800 sq ft if the impact fee matters: since July 1, 2026 an ADU of 800 sq ft or less pays no park, transportation or fire impact fee, while an 801 sq ft unit pays about $4,189 and a 1,200 sq ft unit about $6,276 on the July-December 2026 schedule
  • Parking is off the table from Sept. 26, 2026 under Ordinance O-4948; if your site plan still shows a required space, cite KZC 115.07(7) as amended. Before that date the half-mile STRIDE (I-405) transit radius was the test
  • Convert before you build where you can: KZC 115.07(6) exempts a permitted conversion of an existing structure, detached garages included, from current setback and lot coverage requirements, provided you do not make an existing nonconformity worse
  • If your lot backs an alley, a detached ADU may go right to the rear property line (KZC 115.115(3)(o)(4); RCW 36.70A.681(1)(i)); otherwise 5 ft, with anything inside the required rear yard held to 15 ft above ABE
  • Start with the pre-approved DADU gallery: four registered plans, a designer licence of up to $1,000, no construction drawings to submit, and expedited review if you stay off shoreline, geohazard and critical-area sites and reuse the existing water meter and sewer
  • Do the floor area ratio maths early. Only the first 500 sq ft (lots under 8,500 sq ft) or 800 sq ft (8,500 sq ft and up) of a detached ADU behind the house is exempt from F.A.R., and F.A.R. is only 20% of lot size in RS 35 (KZC 15.30.060, DD-12)
  • You can sell it: KZC 115.07(2)-(3) allows an ADU to be segregated in ownership and, outside stacked units, put on its own unit lot; shoreline lots are the exception (one ADU and no separate ownership in Residential-L, a Substantial Development Permit in M/H)
  • Check the Property Search map for streams, wetlands and slopes first, not last: RCW 36.70A.681(4) switches off every state protection on a lot designated with critical areas or their buffers, and Kirkland updated its Critical Areas Ordinance in December 2025
  • Cost basis: $325,000-$550,000 and $400-$650 per sq ft are the Seattle-Eastside 2025-26 industry guides used for Seattle and Bellevue (no Kirkland-specific survey is published); rents are HUD FY2026-FY2027 small-area fair market rents for ZIPs 98033 and 98034
  • Cost basis (2026-09-20 re-verification): short term allowed: Yes, with a Washington state and a City of Kirkland business licence, and the city's short-term rental page answers the ADU question directly: a registered detached ADU may be rented short-term (under 30 days) without limit if the owner or an authorised agent lives on the property continuously as a primary residence, with no more than two short-term rentals at once; if the owner lives there at least 245 days a year but not continuously, short-term rentals are capped at 120 days a year and a property manager within 15 miles must be named; a property that is nobody's primary residence may only be rented long-term (Ordinance O-4607, 2017; KMC 7.02.300). Lodging tax is paid to the state. | roi estimate: 6-9% gross rental yield on a $350,000-$550,000 detached build renting at $2,500-$3,300/mo, before vacancy, taxes, the new impact fee and financing; a conversion of existing space at $100,000-$225,000 yields roughly twice that

ADU Builders in Kirkland

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Sources & References

All data on this page is sourced from official government records and verified market data. View our full methodology.

  1. Ordinance O-4905 (adopted 6/17/2025, published 6/27/2025, effective 7/2/2025), Exhibit J: KZC 115.07, 115.08, 115.42, 115.115(3)(o) as amended; Exhibit B: KZC 15.20.060 PU-21/PU-23 Municipal Code — Accessed 2026-09-20
  2. Ordinance O-4948 (passed 9/15/2026, published 9/21/2026), Section 47 and Exhibit L: KZC 115.07(7) parking exemption for ADUs; full current text of KZC 115.07 and 115.115(3)(o) Municipal Code — Accessed 2026-09-20
  3. Kirkland Zoning Code 115.07 Accessory Dwelling Units (Ord. 4913 § 17, 2025; Ord. 4905 § 10, 2025) — current codification Municipal Code — Accessed 2026-09-01
  4. Kirkland Zoning Code 15.30.060 Density/Dimensions table and Special Regulations DD-7, DD-9, DD-11, DD-12, DD-15, DD-16 (Wayback capture of 5/29/2025) Municipal Code — Accessed 2026-09-20
  5. RCW 36.70A.681 Accessory dwelling units, limitations on local regulation (2023 c 334 s 4, HB 1337) state_statute — Accessed 2026-09-20
  6. RCW 35A.21.445 Minimum parking requirements (SB 5184, 2025) state_statute — Accessed 2026-09-20
  7. ADU Regulations — City of Kirkland ADU Toolkit (size, number, ownership, shoreline exceptions, major transit stop) Planning Department — Accessed 2026-09-20
  8. Middle Housing Code Amendments — City of Kirkland (Ordinance O-4905 summary of ADU changes) Planning Department — Accessed 2026-09-20
  9. City Ordinances 2025 and 2026 — Kirkland Content Manager WebDrawer register (O-4905, O-4907, O-4910, O-4913, O-4918, O-4938, O-4948 titles and dates) Municipal Code — Accessed 2026-09-20
  10. ADU Permitting Process — City of Kirkland ADU Toolkit (MyBuildingPermit, submittal list, expedited review) Planning Department — Accessed 2026-09-20
  11. Planning Your ADU — City of Kirkland ADU Toolkit (approximately 3 months for a standard ADU permit) Planning Department — Accessed 2026-09-20
  12. Explore Kirkland's Pre-Approved Plans and Gallery of Pre-Approved ADU Plans — City of Kirkland (four registered DADU plans; licence up to $1,000) Planning Department — Accessed 2026-09-20
  13. Pre-Approved Accessory Dwelling Unit Program: Using a Registered Pre-Approved Plan (submittal requirements, expedited review qualifications) — Kirkland Planning and Building Planning Department — Accessed 2026-09-20
  14. Building Services Fees effective January 1, 2026 — KMC Table 3 building permit fees, 65% plan review, energy code fee, SBCC, 3.5% technology fee, $179 hourly Planning Department — Accessed 2026-09-20
  15. Land Use Permit Fee Schedule 2026 — Planning Official Decisions: Accessory Dwelling Unit $634 (not required if reviewed concurrently with a building permit) Planning Department — Accessed 2026-09-20
  16. Impact Fee Changes Effective July 1, 2026 — notice (ADUs over 800 sq ft charged park, transportation and fire impact fees; worked examples) Planning Department — Accessed 2026-09-20
  17. Park, School, Fire and Transportation Impact Fee Schedules, July-December 2026 (KMC 27.04, 27.06, 27.08, 27.10; Ordinances O-4901, O-4904, O-4910) Planning Department — Accessed 2026-09-20
  18. Development Services Fee Changes Effective January 1, 2026 — notice (2.7% CPI-W; ADU impact-fee phase-in from July 1, 2026) Planning Department — Accessed 2026-09-20
  19. Cost to Build a DADU in Seattle (2025-2026 Update) | Ballard Backyard Cottages industry — Accessed 2026-09-19
  20. How Much Does It Cost to Build an ADU in Seattle? 2026 Guide (Jan. 8, 2026) | Kolmo industry — Accessed 2026-09-19
  21. Seattle ADU Cost 2026 by Type and Size (updated May 12, 2026) | ADU Glossary industry — Accessed 2026-09-19
  22. Prefab ADU 2026: Brands, True Costs (updated May 19, 2026) | OwnADU industry — Accessed 2026-09-19
  23. HUD FY 2026 and FY 2027 Small Area Fair Market Rents, Seattle-Bellevue, WA HUD Metro FMR Area, ZIP codes 98033 and 98034 Government Data — Accessed 2026-09-20
  24. Short-Term Rentals in Kirkland — City of Kirkland (Ordinance O-4607, 2017; licence, 245-day and 120-day rules; ADU FAQ) Planning Department — Accessed 2026-09-20
  25. Moving In or Renting Out — City of Kirkland ADU Toolkit (business licence required for any rental) Planning Department — Accessed 2026-09-20
  26. Kirkland Municipal Code 7.02.030 and 7.02.300 — Business licences; short-term rentals, special provisions Municipal Code — Accessed 2026-09-01
  27. The Kirkland ADU Toolkit — City of Kirkland Planning Department — Accessed 2026-09-20
  28. U.S. Census Bureau QuickFacts — Kirkland city, Washington Government Data — Accessed 2026-09-01

Frequently Asked Questions

Can I build an ADU in Kirkland?

Yes. ADUs are allowed in Accessory use wherever a Detached Dwelling Unit is permitted in the low density zones RS, RSX, RSA, PLA 3C, PLA 6E and PLA 16 (KZC 15.20.060, Special Regulation PU-23). The WD II waterfront row does not carry PU-23, and PU-21 limits RSA 4 lots in the Goat Hill Overlay to one attached ADU. Middle-housing sites may add two attached ADUs (Chapter 113 KZC). Residential-L shoreline lots get one ADU; lots with designated critical areas or buffers lose the state floor (RCW 36.70A.681(4)). in Kirkland. The maximum size for a detached ADU is 1,200 sq ft of gross floor area (KZC 115.07(4)), above the 1,000 sq ft floor in RCW 36.70A.681(1)(f). Not counted: area under 5 ft of ceiling, uncovered rooftop decks or at-grade patios, and up to 200 sq ft of other exterior elements. Ordinance 4905 took ADUs out of the KZC 115.08 accessory-structure cap. Floor area ratio still bites: only the first 500 sq ft (lot under 8,500 sq ft) or 800 sq ft (8,500 sq ft and up) of a detached ADU behind the house is exempt from F.A.R. (KZC 115.42(1)(c)-(d)).. Owner-occupancy is not required, so you can rent out the ADU.

How much does an ADU cost in Kirkland?

ADU construction in Kirkland typically costs $325,000-$550,000. Garage conversions run $100,000-$225,000, and prefab ADUs cost $300,000-$450,000.

How much can I rent an ADU for in Kirkland?

Average ADU rents in Kirkland are $2,450-$2,850/mo for a 1-bedroom and $2,850-$3,350/mo for a 2-bedroom unit.

Do I need parking for an ADU in Kirkland?

None. Ordinance O-4948 (passed Sept. 15, 2026, effective Sept. 26, 2026) rewrites KZC 115.07(7): ADUs are exempt from any minimum vehicle parking requirement, citywide, implementing SB 5184 (RCW 35A.21.445, no parking minimums for homes under 1,200 sq ft). Until then the rule was none within a half mile of a major transit stop (the STRIDE I-405 station) and one space only for a second ADU elsewhere; the city's ADU Regulations page still shows that older text, so cite O-4948 if asked for a space.. Check with Kirkland planning department for the latest Washington ADU parking rules, as many states have relaxed requirements in recent years.

How long does it take to get an ADU permit in Kirkland?

The permit review timeline in Kirkland is About 3 months for a standard ADU permit, plus design and construction time (City Planning Your ADU page, 2026). A registered pre-approved DADU that qualifies for expedited review can be approved in as little as a few weeks; shoreline, geohazard and critical-area sites do not qualify.. Permit fees: 2026 building permit on valuation (KMC Table 3: $1,620 plus $8.22 per $1,000 over $100,000), plan review at 65% of it, a $101 + $0.01/sq ft energy-code fee and a 3.5% technology fee: about $5,700 on a $300,000 detached ADU before plumbing, fire and utility charges. Plan licence up to $1,000.

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Kirkland ADU FAQ

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Kirkland ADU Costs

Detailed cost breakdown: construction $325,000-$550,000, garage conversion $100,000-$225,000, plus ROI analysis.

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Garage Conversion ADU Guide

Complete guide to costs ($80K-$180K), impact fee savings, and permits for garage-to-ADU conversions.

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ADU vs Mother-in-Law Suite

Legal differences that affect what you can build, how you can use it, and rental rights.

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About this information: This page is an informational summary of publicly available regulations - it is not legal, financial, or professional advice, and it is not a substitute for confirming requirements with your local planning department. Rules change frequently; always verify current requirements before designing, budgeting, or building. Last verified: 2026-09-20. Contractors we introduce are independent businesses - verify license and insurance directly before hiring. Spotted an error? Tell us - we verify against primary sources and correct quickly.

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