DADU feasibility · Fremont
Building a DADU in Fremont
Fremont has more small lots and more multifamily zoning mixed into the residential fabric than almost anywhere else on this list.
This profile is measured from City of Seattle open data across 4,979 parcels in Fremont — not estimated, and not the same numbers as any other neighborhood on this site.
Lot sizes in Fremont
A third of Fremont's parcels are under 3,200 sq ft — the smallest median lot in this set. It also has an unusually large Lowrise share, which changes the calculation entirely: on LR-zoned land the question shifts from 'does a cottage fit' to 'is a cottage the best use of the FAR you have.'
Parcel counts by lot size, Fremont. Source: King County parcels via Seattle's ADUniverse dataset.
70% of parcels here are under 5,000 sq ft and 30% are 5,000 sq ft or larger — a low 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 Seattle repealed the old 3,200 sq ft minimum lot area for a DADU, so small lots are no longer excluded; they are simply governed by the floor-area budget instead.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
The ground is mostly stable, with steep slope confined to the hillside edges running up toward Phinney and down toward the ship canal. Liquefaction appears in the low ground near the water.
Fremont 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
Physical fit on a small lot
70% 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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02
Side sewer, water and electrical capacity
38% of buildings here predate 1940 and 12% 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
Protected trees
Tree canopy covers 26.6% of Fremont (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.
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04
Liquefaction and soil conditions
4.9% of Fremont 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
Slope and landslide-prone ground
3.9% of Fremont is mapped as steep slope (40% or greater) and 0.1% 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.
Zoning and utilities
Zoning mix
- SF 50002,212 parcels
- LR1872 parcels
- LR3749 parcels
- LR2484 parcels
- IB U/4599 parcels
45.3% of parcels are Neighborhood Residential or Residential Small Lot; 42.9% 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 194038%
- 1940 – 197512%
- After 197546%
Mixed vintages. The bigger Fremont-specific issue is construction access — narrow lots with buildings close to the line often leave no route for equipment to reach a rear yard.
Fremont DADU questions
Can I build a DADU in Fremont?
In almost all cases the zoning allows it. 45.3% of parcels in Fremont 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 Fremont?
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. With 70% of Fremont parcels under 5,000 sq ft, the cap is usually academic here — the lot-wide budget runs out first, and a 600–800 sq ft cottage is the realistic target.
What is most likely to block a DADU in Fremont?
Physical fit on a small lot — 70% 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.
Do I need a feasibility study before designing a DADU in Fremont?
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 Fremont 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 Fremont lot.
This page tells you what Fremont 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.