ADU Builder in Bellevue, WA
Dream Dadu is Bellevue’s hometown ADU builder — our headquarters is right here in the city. We design, permit, and build accessory dwelling units, attached or detached, that add living space, rental income, and long-term value to your property.
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Backyard Cottages Are Finally Legal in Bellevue
Here’s the headline most Bellevue homeowners haven’t caught up with: detached ADUs (DADUs) only became legal in Bellevue on July 1, 2025, under the city’s middle-housing ordinance. If you looked into a backyard cottage a few years ago and were told no — the answer has changed. The current rules are genuinely homeowner-friendly:
- Two ADUs per lot on any lot that allows a single-family home — attached, detached, or both
- Up to 1,200 sq ft of floor area, plus up to 300 sq ft of exempt parking/storage space
- Up to 24 feet tall — 28 feet when built above an existing accessory structure
- No parking required if the ADU is under 1,000 sq ft or within a half-mile of major transit
- No owner-occupancy requirement — live on-site or don't
- ADUs can be sold separately as condominiums — a genuine equity asset
Verified July 2026 against Bellevue Land Use Code 20.20.120 (Ordinance 6851). Every lot is different — we confirm what current code allows on your property during a free feasibility visit.
Why Build an ADU in Bellevue?
An ADU (accessory dwelling unit) is a second, self-contained home on your lot — attached to or within your house, or a fully detached backyard cottage (a DADU). In Bellevue, where home values are among the strongest in the state, that extra unit works hard:
Rental income
A private unit in one of the Eastside's most in-demand rental markets.
Multigenerational living
Aging parents or adult children close by — with privacy on both sides.
Lasting property value
A permitted second dwelling is a durable asset, not a remodel.
Flexible space
Home office, studio, or guest suite that adapts as life changes.
Our Design-Build Process
One accountable team from first sketch to final inspection — no juggling separate architects, permit expeditors, and contractors.
- 1. Consultation & feasibility — we evaluate your lot and what Bellevue's code allows
- 2. Design — an ADU shaped to your property, budget, and goals
- 3. Permitting — we prepare and manage your MyBuildingPermit submittals with the City of Bellevue
- 4. Construction — one team, clear milestones, steady communication
- 5. Rental- or family-ready — inspections handled, ready to use
Bellevue ADU Questions, Answered
Can I build a detached ADU (DADU) in Bellevue now?
Yes — and this is news to most Bellevue homeowners: detached ADUs were prohibited in Bellevue until July 1, 2025, when the city’s middle-housing ordinance legalized them citywide. If you looked into a backyard cottage a few years ago and were told no, the answer has changed.
How many ADUs does Bellevue allow on my lot?
Two, on any lot that allows a single-family home — attached, detached, or one of each. One wrinkle worth knowing: a lot can’t combine an ADU with a registered home-occupation business, so we check that during feasibility.
Do I need parking or to live on-site for a Bellevue ADU?
Owner-occupancy: no — Bellevue removed that requirement in 2023. Parking: none required if the ADU is under 1,000 square feet or within a half-mile of a major transit stop; otherwise one space. We confirm which case applies to your address.
What permits does a Bellevue DADU need?
A DADU is permitted as a "New One- or Two-Family structure" building permit, submitted through the regional MyBuildingPermit portal. We prepare and manage the whole submittal. Bellevue is also developing a pre-approved DADU plans program — ask us whether waiting for it makes sense for your project.
Can I sell my Bellevue ADU separately?
Yes. Since Bellevue’s 2023 ADU reform, an ADU can be sold separately as a condominium — which turns a backyard cottage into a genuine equity asset, not just a rental. Our financing team can walk you through how condo-izing works.
Start Your Bellevue ADU
Let’s talk through what’s possible on your lot. Schedule a free consultation and we’ll give you a clear, honest assessment.