DADU feasibility · Ballard
Building a DADU in Ballard
Ballard's north-of-Market blocks are classic 1920s–40s platting: long, narrow lots laid out before anyone imagined a second house behind the first.
This profile is measured from City of Seattle open data across 5,133 parcels in Sunset Hill/Loyal Heights — not estimated, and not the same numbers as any other neighborhood on this site.
Lot sizes in Ballard
Most Ballard lots fall in the 3,200–7,200 sq ft band, and the narrowness matters more than the total. On a 40-foot-wide lot, a 5 ft average side setback on both sides leaves roughly 30 feet of buildable width — workable for a cottage, but it forces the design before you ever draw it.
Parcel counts by lot size, Sunset Hill/Loyal Heights. Source: King County parcels via Seattle's ADUniverse dataset.
54% of parcels here are under 5,000 sq ft and 46% are 5,000 sq ft or larger — a middling share among the 18 areas profiled here. Seattle repealed the old 3,200 sq ft minimum lot area for a DADU, so small lots are no longer excluded; they are simply governed by the floor-area budget instead.
What the ground looks like
Ballard sits low and close to the water, and the alley grid is unusually complete for Seattle. A rear yard that abuts a platted alley gets a 0 ft rear setback, which is the single biggest siting advantage available anywhere in the city — it is worth confirming your alley status before anything else.
Ballard against the median of the 18 Seattle areas profiled here. Hazard layers clipped to the neighborhood boundary; canopy is area-weighted by census block group.
What decides feasibility here, in order
Ranked by what this neighborhood's own measurements say — not a generic checklist.
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01
Slope and landslide-prone ground
7.8% of Ballard is mapped as steep slope (40% or greater) and 7.7% as potential landslide area, against Seattle medians of 7.7% and 4.4% across the areas profiled here. Land inside an Environmentally Critical Area under SMC 25.09 triggers additional review and, in practice, a geotechnical report before design.
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02
Side sewer, water and electrical capacity
41% of buildings here predate 1940 and 28% were built between 1940 and 1975. Older stock means older side sewers and smaller electrical services — the two utility findings that most often reset a DADU budget.
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03
Physical fit on a small lot
54% of parcels here are under 5,000 sq ft. Lot size no longer disqualifies a DADU, but on a tight lot the lot-wide FAR and lot-coverage budget — which ADU floor area now counts toward — usually binds before setbacks do.
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04
Liquefaction and soil conditions
8.8% of Ballard sits on mapped liquefaction-prone soils (Seattle median here: 8.7%). This rarely stops a project, but it changes foundation design and belongs in the budget before you price a build.
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05
Protected trees
Tree canopy covers 26.9% of Ballard (Seattle median here: 26.9%). Seattle's tree code (SMC 25.11) protects trees by tier, and a Tier 2 tree with its root protection area falling across your rear yard can move or shrink a cottage even on a large lot.
Zoning and utilities
Zoning mix
- SF 50003,945 parcels
- LR2365 parcels
- LR1302 parcels
- LR3240 parcels
- NC1-4042 parcels
77.9% of parcels are Neighborhood Residential or Residential Small Lot; 17.9% are Lowrise. Zone labels reflect the parcel dataset's legacy single-family categories, which map into today's Neighborhood Residential zone under Ordinance 127376.
Housing age
- Before 194041%
- 1940 – 197528%
- After 197529%
The older housing stock means older side sewers. Ballard has a high share of pre-1940 homes, which is exactly the vintage where clay side sewers with root intrusion show up on a camera inspection.
Ballard DADU questions
Can I build a DADU in Ballard?
In almost all cases the zoning allows it. 77.9% of parcels in Ballard sit in Neighborhood Residential or Residential Small Lot zoning, where detached accessory dwelling units are permitted, and Seattle removed both the old minimum-lot-size test and the owner-occupancy requirement. The real question is whether a compliant cottage physically fits your lot and whether utilities can serve it.
How big can a DADU be in Ballard?
The citywide caps apply: 1,000 sq ft of gross floor area for an ADU with up to two bedrooms, or 1,200 sq ft with three or more. On top of that, your lot has a single FAR and lot-coverage budget shared with the existing house — which is what actually limits most projects. 46% of Ballard parcels are 5,000 sq ft or larger, so whether you reach the cap depends heavily on which block you are on.
What is most likely to block a DADU in Ballard?
Slope and landslide-prone ground — 7.8% of Ballard is mapped as steep slope (40% or greater) and 7.7% as potential landslide area, against Seattle medians of 7.7% and 4.4% across the areas profiled here. Land inside an Environmentally Critical Area under SMC 25.09 triggers additional review and, in practice, a geotechnical report before design.
Do I need a feasibility study before designing a DADU in Ballard?
You are not required to have one. But the checks that decide feasibility — setbacks against the existing house, FAR headroom, tree tiers, mapped critical areas, side sewer condition, and construction access — are all cheaper to answer before you commit to an architect or a plan set than after. In Ballard specifically, start with the side sewer and the panel — on flat, stable ground like this, utilities are what most often reset the budget.
Next step
Run these checks on your own Ballard lot.
This page tells you what Ballard looks like as a whole. The Seattle DADU Pro Guide walks your specific address through the same review — setbacks and FAR headroom, tree tiers, mapped critical areas, side sewer and panel capacity, the permit roadmap, and a scoring template you fill in yourself.