Puget Sound & San Juan Islands

ADUs, cabins, and small homes on the islands

We build on Vashon, Bainbridge, Whidbey, Camano, the San Juans, and the smaller South Sound islands. We file the county permit, build your home in our factory in Battle Ground, in Southwest Washington, and get it over the bridge or onto the ferry. On an island, the first thing we figure out is how the house gets to your lot.

Free Property Evaluation Find your island

Where Wolf works

In Washington and Oregon, Wolf employees handle your project from property review and permits through construction, site work, delivery, and installation. Some projects require third-party services, such as surveys or septic design and installation, depending on the property and jurisdiction. Beyond Washington and Oregon, local contractors complete site work and utility connections.

Navy Wolf Model I home with a metal roof, cedar-shake gable, and wood porch stairs beside the water and tall evergreens near Shelton, Washington — A Wolf Model I on the water near Shelton, in Mason County.

Getting there

How the home gets to the island

The first thing we ask on any island job is whether a module can get from our factory to your lot. That comes down to whether your island has a bridge, a state ferry, or just a county boat.

Bridge islands

We drive the home on like any rural delivery. It’s still an oversize load, but planning it feels like a mainland job: the route, the trees, overhead lines, and where the crane sets up.

Bainbridge, Camano, Fox, Marrowstone, Harstine, and north Whidbey

Washington State Ferries

On a state ferry, your home counts as an oversize vehicle. We request the crossing with the home’s dimensions, work around commuter sailings and the tides, and line up a backup sailing. If the weather turns or we miss the boat, the schedule slides.

Vashon, the San Juans, and south Whidbey

County ferries and barges

County boats have smaller decks and their own rules. If your island has no car ferry, we need a barge landing and a crane plan. We look at each of these one at a time, and if a module can’t realistically get there, we’ll tell you.

Anderson, Guemes, Lummi, and islands without car-ferry service

Island by island

Who permits it and how the home gets there

Every island falls under a county, and a few have their own city or town. Find yours below, then open the county guide for the full ADU rules.

Vashon and Maury Island

Washington State Ferry

Burton, Dockton, Portage, Quartermaster Harbor

Permits:: Unincorporated King County (Department of Local Services) (King County)
Delivery:: Washington State Ferries from Fauntleroy (West Seattle), Point Defiance–Tahlequah (Tacoma), or Southworth.

There’s no City of Vashon, so King County issues the permit and Public Health signs off on your septic or sewer. Most lots are on septic. If you’re in the town core, you probably have sewer and Water District 19 water, which makes life easier. The house rides over on a state ferry as an oversize load, so we book the sailing and look at the tides and island roads before we get into floor plans. We’ve done it before: the crew housing we built for Vashon Fire and Rescue went over on the boat.

Bainbridge Island

Bridge — drive-on

Winslow, Rolling Bay, Port Blakely, Fletcher Bay

Permits:: City of Bainbridge Island (Kitsap County)
Delivery:: Trucks drive on over the Agate Pass Bridge (SR 305) from the Kitsap Peninsula. The home doesn’t need a ferry.

The whole island is one city, so your permit goes to the City of Bainbridge Island rather than Kitsap County, and the city writes its own ADU rules. Because we can drive over the Agate Pass Bridge, Bainbridge can take wider plans that would be a headache on a ferry. We recently set a two-bedroom, two-bath Model J on a wooded lot there.

Whidbey Island

Bridge or state ferry

Oak Harbor, Coupeville, Langley, Freeland, Clinton, Greenbank

Permits:: Island County, or the City of Oak Harbor, Town of Coupeville, or City of Langley inside their limits (Island County)
Delivery:: Drive on from the north over the Deception Pass Bridge (SR 20), or cross on the Mukilteo–Clinton or Port Townsend–Coupeville ferries.

Island County updated its ADU rules in June 2026. You can now build up to 1,296 gross square feet, a detached unit generally has to sit within 150 feet of the main house, and the rural zones still have a yearly cap on detached ADU permits. Most rural lots are on a well and septic, and the county wants the septic design and water availability when you apply. If your lot is on the south end, we’ll weigh the long drive around through Deception Pass against a ferry crossing.

Island County ADU rules

Camano Island

Bridge — drive-on

Camano, Utsalady, Juniper Beach

Permits:: Unincorporated Island County (Island County)
Delivery:: Drive on over the SR 532 bridge from Stanwood. No ferry.

Camano is part of Island County, so the same ADU code and detached-permit cap apply as on rural Whidbey. Getting there is easy, just a short drive off I-5. The work usually goes into bluffs, shoreline setbacks, and septic.

Island County ADU rules

San Juan Islands

Washington State Ferry

San Juan Island, Friday Harbor, Orcas Island, Eastsound, Lopez Island, Shaw Island

Permits:: San Juan County, or the Town of Friday Harbor inside town limits (San Juan County)
Delivery:: Washington State Ferries from Anacortes to Lopez, Shaw, Orcas, and Friday Harbor. Islands without car-ferry service need a barge.

San Juan County has the toughest ADU rules of any county on this page. Outside urban growth areas and activity centers, a detached ADU goes through a yearly eligibility process, and if too many people apply, it’s a lottery. The unit tops out at 1,000 square feet of living area, and rural detached units need at least five acres. Detached ADUs permitted since 2007 can’t be vacation rentals. If your land is vacant, a small primary home or cabin is often the easier permit.

San Juan County ADU rules

Fox Island

Bridge — drive-on

Permits:: Unincorporated Pierce County (Pierce County)
Delivery:: Drive on over the Fox Island Bridge from the Gig Harbor peninsula.

Fox Island is unincorporated Pierce County, and you get there on a two-lane bridge instead of a boat. Shoreline, slopes, and septic are what usually come up. We check the bridge route and any load limits when we look at your site.

Anderson Island

County ferry

Ketron Island

Permits:: Unincorporated Pierce County (Pierce County)
Delivery:: Pierce County ferry from Steilacoom.

Anderson runs on a county ferry, not Washington State Ferries, so the county sets the deck space, the ramp, and the schedule. Before we quote a plan, we make sure the home will actually fit on that boat.

Pierce County ADU rules

Guemes Island

County ferry

Permits:: Unincorporated Skagit County (Skagit County)
Delivery:: Skagit County ferry from Anacortes.

It’s a short county-ferry ride from Anacortes. Between the wells, the septic, and the size of the county boat, we usually start with a compact single-wide here.

Skagit County ADU rules

Lummi Island

County ferry

Permits:: Unincorporated Whatcom County (Whatcom County)
Delivery:: Whatcom County ferry from Gooseberry Point.

Lummi is another county-run crossing with its own vessel limits. We look at the boat, the landing, and the road to your lot before we recommend a model.

Whatcom County ADU rules

Marrowstone Island

Bridge — drive-on

Nordland

Permits:: Unincorporated Jefferson County (Jefferson County)
Delivery:: Drive on via SR 116 from Port Hadlock.

You can drive onto Marrowstone from Port Hadlock, just outside Port Townsend, and it’s unincorporated Jefferson County. Shoreline setbacks, wind, and salt air are the main design questions. If you’re close to the water, ask us about the optional Coastal Package.

Harstine Island

Bridge — drive-on

Permits:: Unincorporated Mason County (Mason County)
Delivery:: Drive on over the Harstine Island bridge.

Harstine is a South Sound island in Mason County with a bridge, so delivery is a regular road trip. Most of the work is on the lot itself: long wooded driveways, wells, and septic.

Mason County ADU rules

Cabin, ADU, or guest house

What the county will call your island cabin

You might call it a cabin, a tiny home, a guest house, or an ADU. The county looks at what’s inside the building and what’s already on your lot, and that’s what decides which rules and caps you’re under.

A cabin behind the house is usually an ADU

If there’s already a house on the lot and the new building has a kitchen and bath, plan on an accessory dwelling unit permit. That brings the county’s size limit, the required distance from the main house, and any yearly cap.

A cabin on vacant land is often the main home

If your island parcel is empty, a small Wolf home can usually be permitted as the main house. That typically keeps you out of ADU lotteries and caps, and you can still build a bigger house later.

Vacation rentals are a separate license

Island counties limit short-term rentals, and San Juan County doesn’t allow them in detached ADUs permitted since 2007. Unless your parcel has a clear rental path, plan the cabin for family, guests, or a long-term tenant.

Vacation and getaway homes Guest homes Tiny homes

On the islands

Wolf homes already on the Sound

We’ve set a two-bedroom Model J on a wooded Bainbridge lot, built staff housing for Vashon’s fire and rescue crew that crossed on the ferry, and put a small house on Whidbey Island.

Wolf Model J on Bainbridge Island with a covered porch deck and board-and-batten siding

Kitchen island inside the Bainbridge Island Model J

Open living area with French doors inside the Bainbridge Island Model J

Vashon Fire and Rescue housing

Crew housing that had to cross on a Washington State Ferry and fit on island roads. Here’s how we pulled off the delivery.

“We worked with Wolf to put a small house on our property on Whidbey Island. All of the staff we interacted with were great. Excellent communications, service, & quality.”

Ed Hartin, Whidbey Island (Google review)

Models

Plans that suit an island lot

Single-section homes are the easiest to get on a ferry and down narrow island roads. Wider plans work better on islands you can drive onto. The prices below are for the home only. We quote island delivery and site work after we’ve looked at your lot.

Model K — 432 sq ft

A one-bedroom cabin or ADU in a single 12×36 section, from $85,500 for the home. It’s the easiest plan to get on a ferry and down a narrow island road.

Model E / F — 616 sq ft

Two bedrooms in a single 14×44 section, from $97,500 for the home. This is our usual family cabin or parent ADU, as long as the septic design allows two bedrooms.

Model J — 828 sq ft

Two bedrooms and two baths with vaulted ceilings, from $156,500 for the home. At 23 feet wide, it’s a better fit for islands you can drive onto, like the Bainbridge home in the photos.

Compare all models

Property evaluation

What we check first on an island lot

The free evaluation starts with your address. On an island, these are the questions we answer before we talk about finishes.

Who issues your permit: the county, or a city like Bainbridge, Oak Harbor, Langley, or Friday Harbor
What kind of home it is (ADU, main house, or guest house) and any yearly ADU cap
Your septic design or sewer certificate, and your well or water district
Shoreline, bluff, wetland, and critical-area rules on the lot
How we get there (bridge, state ferry, county ferry, or barge) and which sailing and tide work
The drive from the dock to your lot: island roads, trees, power lines, driveway grade, and room for the crane

Island jobs have some costs a mainland lot doesn’t: ferry fares for the truck and crew, oversize-transport permits, crew travel time, and warranty visits that also cross the water. You’ll see each of those as its own line in the proposal. See cost and financing.

Questions

Island ADU and cabin questions

Can you deliver a modular home to Vashon or the San Juan Islands by ferry?

Yes. Your home crosses on Washington State Ferries as an oversize load. We book the sailing with the home’s dimensions, time the foundation and crane around that date, and keep a backup sailing lined up. Our Vashon fire-crew housing project went over on the boat. Single-section plans like Model K and Model E are the easiest to ferry.

Which Puget Sound islands can you drive a house onto?

Bainbridge (Agate Pass Bridge), Whidbey from the north (Deception Pass Bridge), Camano (SR 532), Fox Island, Marrowstone, and Harstine all have bridges, so delivery there works a lot like a rural mainland job. Vashon, the San Juans, Anderson, Guemes, and Lummi need a ferry.

Is a cabin an ADU?

It depends on what’s already on the lot. If there’s a house and the cabin has a kitchen and bath, the county will usually call it an accessory dwelling unit. On vacant land, that same cabin is often permitted as your primary home, which gets you around ADU limits like the San Juan County lottery and the Island County detached-permit cap. A cabin without a kitchen might be a guest house or accessory structure, and those follow different rules. We’ll confirm which one your parcel falls under.

Do island counties limit how many ADUs they approve?

Some do. San Juan County runs a yearly eligibility process for detached ADUs outside urban growth areas, and it holds a lottery when more people apply than there are slots. Island County (Whidbey and Camano) caps detached ADU permits each year in its rural zones. Check the San Juan County and Island County guides, and get the current count from the county before you commit to a design.

Can I use an island ADU or cabin as a vacation rental?

Don’t count on it. San Juan County doesn’t allow detached ADUs permitted since 2007 to be vacation rentals, and short-term rental permits are limited across the islands. We build the home, and the lodging license is up to you as the owner. Read vacation rental ADUs before you plan around nightly income.

How much more does an island project cost?

The home costs the same. The site work costs more: ferry fares for the truck and crew, oversize-transport permits, crew travel time, crane access, septic design, and sometimes tree work or a longer utility run. Our published installation baseline covers sites within 20 miles of the factory, so we quote island delivery and setup after we’ve looked at your site. The cost page has the baseline.

Do you handle permits with King, Kitsap, Island, and San Juan counties?

Yes. We put together and file the local placement permit while Washington L&I inspects your home in our factory. The county, or the city if you’re on Bainbridge or in Oak Harbor, Langley, Coupeville, or Friday Harbor, reviews zoning, the foundation, septic or sewer, and the hookups.

What about salt air and island weather?

Every Wolf home is built to the Washington residential code for Northwest weather. If you’re on the waterfront or an exposed lot, ask about the optional Coastal Package for extra protection against salt air and marine weather.

Keep reading

Related Wolf pages

Vashon ADUs

King County permits, ferry routes, septic, and island roads.

Modular homes for remote sites

Why factory-built homes work well on ferry islands and hard-to-reach land.

ADUs in Washington

HB 1337, urban growth areas, and how rural lots differ.

How a project works

From the first evaluation to permits, the factory build, delivery, and warranty.

Tell us which island

Send us the address, let us know if there’s already a house on the lot, and tell us who the home is for: family, guests, a parent, or a long-term tenant. We’ll look at the permit, septic and water, and whether a module can make it over the bridge or onto the boat.

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Free Property Evaluation Call (360) 912-9519

Where on the property have you pictured it?

The spot you enjoy most is a good place to begin the conversation. Then we check the local rules, the delivery path and utility connections. A mailing address alone doesn’t tell us which jurisdiction reviews the project.

Tell us about the property →