"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
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Shoreline ADU & DADU rules, in plain English
What Shoreline'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.
SMC 20.40.210 No parking minimums since Aug 2025 2 ADUs per lot, any mix
The Update
What changed in Shoreline.
Shoreline adopted its HB 1337 and middle housing rules in Ordinance 1027 in January 2025, and in August 2025 repealed all parking minimums. The ADU rules sit in SMC 20.40.210, with the city's Neighborhood Residential handbook explaining them (city code updates page).
Some older city pages still mention owner occupancy. The code removed it.
Rules for other cities are in our ADU rules by city guide.
Shoreline · SMC 20.40.210
Shoreline'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.
1,200sq ft
Size cap
An interior ADU on its own floor can be larger.
23–35feet
Height
The zone's limit: NR3 to NR1, plus pitched-roof allowances.
0
Parking spaces
Shoreline repealed all parking minimums.
The Code
Shoreline ADU rules, line by line.
The main single-family zones. Zone-specific numbers vary, so we confirm them for each lot.
| Rule | What Shoreline allows | Source |
|---|---|---|
| ADUs per lot | Two, attached or detached, in any combination. They count toward the zone's maximum density. | SMC 20.40.210 |
| Size | 1,200 sq ft. An ADU on a separate floor inside the house can be larger. | SMC 20.40.210 |
| Height | The zone's limit: 23 feet in NR3 (28 feet to a pitched ridge), 30 to 35 feet in NR2, 35 to 40 feet in NR1. Two-story DADUs fit. | SMC Table 20.50.020(1) |
| Setbacks | Front 10 feet, side 5 feet, rear 10 feet in NR3 and NR2 (5 feet in NR1). A DADU's side or rear setback can be 0 next to an alley. | SMC Table 20.50.020(1) |
| Hardscape | Up to 50% in NR3, with higher limits in NR2 and NR1 when a lot has two or more units. | SMC Table 20.50.020(1) |
| Minimum lot size | No ADU-specific minimum. | SMC Table 20.50.020(1) |
| Parking | None. Shoreline repealed its parking minimums in August 2025. | City parking update |
| Owner occupancy | Not required. | SMC 20.40.210 |
| Selling separately | The city's handbook says an ADU can be sold separately as a condominium. | City handbook page |
| Design | Certain building design standards don't apply to buildings more than 60 feet from the street or behind another building. We check whether the exception applies to each DADU. | SMC 20.50.090 |
| Trees | Significant trees are 6 inches and up. Development keeps 35% of significant trees, and removing a tree 24 inches or larger adds replacement and a tree-fund fee. | SMC 20.50.350 |
| Street improvements | ADUs are exempt from frontage improvements. | SMC 20.70.320 |
| Fire | Shoreline's fire code requires sprinklers in new one- and two-family dwellings, and a driveway may need widening for fire access. We confirm what applies to each DADU. | SMC 15.05.040 |
Checked October 28, 2026. Sources: SMC 20.40.210, SMC Table 20.50.020(1), SMC 20.50.350, the city parking update, the Neighborhood Residential handbook page and RCW 36.70A.681. A plain-English summary, not legal advice. The code governs, and we confirm it for your lot.
Your Lot
How we check a Shoreline 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 Shoreline'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 Shoreline, 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
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FAQs · Shoreline ADU rules
Shoreline ADU questions we hear on site visits.
Short answers from the code. For your exact lot, call us or book the free site visit.
Two, attached or detached, in any combination. They count toward the zone's maximum density.
1,200 square feet. An ADU on a separate floor inside the house can be larger.
The zone's limit: 23 feet in NR3, or 28 feet to a pitched ridge, and more in NR2 and NR1.
No. Shoreline repealed all parking minimums in August 2025.
Shoreline's fire code requires sprinklers in new one- and two-family dwellings. We confirm with the city what applies to each DADU design.
Contact Us · Free Estimate
Tell us about your project.
We'll check your address against Shoreline'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 Shoreline'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