"We hired MNBE to build our ADU in Bellevue, and the entire experience was amazing. They handled everything from foundations and framing to kitchen, siding, windows and HVAC."
Zena Heywood
Bellevue, WA · Attached ADU
FIVE-STAR RATEDRATED ON GOOGLE
LICENSED · BONDED& FULLY INSURED
Tukwila ADU & DADU rules, in plain English
What Tukwila's code allows for attached and detached ADUs today, rule by rule, with the code section behind each one. Written by MNBE founder Aharon Ben Elisha. Checked October 28, 2026.
TMC 18.50.220 1,400 sq ft ADUs No ADU parking
The Update
What changed in Tukwila.
Tukwila rewrote its ADU rules with its middle housing update, Ordinance 2765, effective June 24, 2025. Ordinance 2792, effective July 28, 2026, added design review for ADUs. The rules sit in TMC 18.50.220.
Water and sewer in Tukwila come from several providers depending on the street, so we confirm the provider on the city's map early.
What we are building in Tukwila
We are designing three new homes at The Court at 44th in Tukwila, and have taken that lot through the city's water and sewer availability steps.
Rules for other cities are in our ADU rules by city guide.
Tukwila · TMC 18.50.220
Tukwila's ADU rules, by the numbers.
The four numbers homeowners ask about first. Check them against your lot with a feasibility study →
2
ADUs per lot
Attached, detached or one of each.
1,400sq ft
Size cap
A detached garage under the ADU doesn't count.
28feet
DADU height
Two-story DADUs fit.
0
Parking spaces
No parking is required for an ADU.
The Code
Tukwila ADU rules, line by line.
The main single-family zones. Zone-specific numbers vary, so we confirm them for each lot.
| Rule | What Tukwila allows | Source |
|---|---|---|
| ADUs per lot | Two: attached, detached, or one of each. In the CR zone ADUs count toward the lot's maximum density. | TMC 18.50.220 |
| Size | 1,400 sq ft. A detached garage under the ADU is not counted. | TMC 18.50.220 |
| Height | 28 feet for a detached ADU. An attached ADU follows the zone's limit. | TMC 18.50.220 |
| Setbacks | In the CR zone: front 15 feet, side 5 feet, rear 5 feet, and 0 feet at the rear on an alley. | Ordinance 2792 |
| Coverage | In the CR zone: building footprint up to 50% and development area up to 75%. | Ordinance 2792 |
| Minimum lot size | None. An ADU is allowed on any parcel regardless of lot size. | City ADU handout |
| Parking | None required. | Ordinance 2765 |
| Owner occupancy | Not required. | City ADU handout |
| Selling separately | Through a unit lot short plat or a condominium. | TMC 17.12.080 |
| Existing structures | Existing nonconforming structures are exempt from setbacks and the development-area maximum. | TMC 18.50.220 |
| Design | Since July 2026, new ADUs follow residential design criteria: street-facing facades meet entry, covered-entry (at least 25 sq ft) and window (at least 20%) standards, facades screened from the street by another building are exempt, and articulation depends on facade width. | Ordinance 2792 |
| Rentals | No rentals under 30 days. Tukwila's rental license and inspection program applies. | TMC 18.50.220 |
| Utilities | Water and sewer providers vary by area. A fire flow certificate comes from the water provider, and a detached ADU needs its own sewer connection split from the house. | Water and sewer handout |
| Trees | A tree permit is needed to remove, or work in the root zone of, significant trees (6 inches and up) and exceptional trees (18 inches and up). | TMC 18.54 |
Checked October 28, 2026. Sources: TMC 18.50.220, Ordinance 2765, Ordinance 2792, the city ADU handout, the water and sewer handout, TMC 18.54 and RCW 36.70A.681. Ordinance 2792 is not yet in the online code, and Ordinance 2800 (October 5, 2026) amends the same chapters, so we confirm the current CR standards for each lot. A plain-English summary, not legal advice. The code governs, and we confirm it for your lot.
Your Lot
How we check a Tukwila lot for an ADU.
The code sets the outer limits. Your lot sets the real ones. This is the order we work in during the free site visit and feasibility.
01
Zone and overlays
We confirm your zone and check Tukwila's maps for critical areas, shoreline and slopes, which can move or shrink the buildable area.
Zoning
02
Trees
We locate the trees the code protects and their root zones before we place the ADU.
Tree code
03
Fit the footprint
We test size, height, setbacks, coverage and floor area against your house, and whether an existing building can be converted.
Footprint
04
Utilities
We check whether water, sewer and power can come from the house or need their own connections.
Utilities
05
Design and permit
We draw the plans in house, submit to Tukwila, answer corrections and carry the project through inspections.
City review
Reviews
What Seattle homeowners say about building with MNBE.
Verified five star reviews from owners we guided through ADU feasibility, permitting, and construction.
"We hired MNBE for a full renovation of our 100 year old home and the results exceeded expectations, structural upgrades, new insulation, a luxury bathroom, a high end kitchen, a new roof and mini split AC."
Dave Gierok
Redmond, WA · DADU
"My mom hired MNBE Construction for her two-bedroom DADU in Seattle, and watching the process up close was impressive. They did it all: design, architectural plans, the building permit, and the full construction. … The communication was excellent and there were never any surprises."
Maryam Z.
White Center, WA · ADU
Schedule Free Estimate
FIVE-STAR RATEDRATED ON GOOGLE
LICENSED · BONDED& FULLY INSURED
FAQs · Tukwila ADU rules
Tukwila ADU questions we hear on site visits.
Short answers from the code. For your exact lot, call us or book the free site visit.
Up to 1,400 square feet, one of the larger limits in the area. A detached garage under the ADU doesn't count.
28 feet, which fits a two-story DADU.
No. Since the June 2025 update, no parking is required for an ADU.
No. Tukwila doesn't allow rentals under 30 days in an ADU, and its rental license program applies to long-term rentals.
It depends on the street: the city or one of several districts. We confirm the provider early, since the fire flow certificate and sewer forms come from them.
Contact Us · Free Estimate
Tell us about your project.
We'll check your address against Tukwila's ADU code and get back to you within one business day with a clear next step.
Contact information
Thank you for considering MNBE. Thank you for considering MNBE. Tell us your address and we will tell you, in writing, what Tukwila's code allows on your lot. We respond within one business day, Monday through Saturday.
(206) 637 0044
info@mnbe-wa.com
2014 Fairview Ave Unit 2308, Seattle, WA 98121