Olympia is the first big city north of our usual southwest Washington area, and the I-5 drive there is easy compared with the rest of Puget Sound. The permit still takes planning. City of Olympia Community Planning and Development reviews lots inside city limits, and Thurston County reviews unincorporated parcels. Lacey and Tumwater have their own city halls. Wolf takes Olympia projects by arrangement: the freeway is easier than Seattle’s, but the job still needs a crane plan and a clean submittal through the city portal.
Each property still gets its own evaluation. For Thurston County, the statewide Washington ADU laws guide covers the statute, and we confirm the requirements with the office that reviews your property. Shelton is nearby, but it’s in Mason County with a different guide and reviewer.
City of Olympia or Thurston County
A South Capitol address, a Cooper Point lot, and an unincorporated Johnson Point parcel can all have an Olympia mailing address, so pull the parcel first. County ADU applications use county forms (Property Information Sheet, residential building, impervious worksheet, and, if you’re on septic, Health). City applications go through the city’s Online Permit Center (SmartGov). Mixing up those packets can cost a month. A lot south of the freeway toward Tumwater is the most common place people guess wrong about the city line.
Washington law allows two ADUs on qualifying properties in urban growth areas. The available space, utility capacity, and any protected areas still affect what you can build. Olympia still sets the site plan rules. Portland’s 800-square-foot cap and Vancouver ePlans don’t apply here.
The city strongly encourages talking with a permit specialist or planner early. Community Planning and Development is at 360-753-8314, cpdinfo@ci.olympia.wa.us. After you submit through the portal, city materials have said to allow 48–72 hours for a status email. Unpaid plan-review fees can cancel an application, and incomplete applications stay in “not submitted” status and can be cancelled too. Have the checklist PDFs ready before you apply, or let us handle the submittal so that 48–72 hour window is just a completeness check.
City stock plans or a Wolf module
Olympia publishes pre-approved ADU stock plans and a stock-plan checklist. With a stock plan, you pick a city drawing, roof, slope, and window package, and you still provide photos of the existing house, a detailed site plan, and drainage documentation when you cross the hard-surface thresholds. That program works well for people who want those designs.
A Wolf home is a factory-built modular dwelling with a Washington L&I insignia, so it goes through a different application. You apply for an Accessory Dwelling Unit building permit with the factory plan set instead of the city PDF. Both paths are legal, and they go to the same CPD staff. If you already requested a stock-plan set and now want a factory module, tell us.
In the Infill Design District, the city requires an ADU to reflect the main house’s architectural style through related roof form and pitch, window patterns, or compatible façade materials and colors. That can affect roof pitch and window layout even though HB 1337 generally limits how much stricter ADU design rules can be than the main house’s. Historic district rules apply in some parts of the city, so we ask which overlay you’re in. Every residential unit, including an ADU, also needs a clearly defined entrance reachable from the street, sidewalk, or driveway by a well-lit paved walkway at least 3 feet wide, kept separate from the driveway unless it’s clearly differentiated. Reviewers look for that walkway, so we draw it from the start.
How Olympia takes a permit
- Confirm whether the lot is in Olympia, Thurston County, Lacey, or Tumwater.
- Talk to CPD if the lot isn’t straightforward (zone, coverage, height, historic district, infill design).
- Register on the SmartGov portal, then apply, upload, and pay.
- Submit a site plan showing the main house, the proposed cottage, utilities, and the walkway.
- Address drainage. The city stock-plan checklist requires extra documentation once hard surface crosses published thresholds, including a full drainage control plan at higher numbers, so check the current checklist for the trigger.
- Schedule inspections and get occupancy through the portal.
Electrical, mechanical, and plumbing may be separate permits.
Lots and neighborhoods
South Capitol and the older east side can be tight, with alleys, trees, and houses close to the property line. The west side and Cooper Point mix woods, slope, and lots that look rural but are still in the city. East Olympia toward Lacey tends to be the most suburban and the easiest to access. Downtown and the isthmus usually aren’t a fit for a backyard cottage.
Thurston soils hold water. Olympia rain on glacial till turns winter excavation into a mud problem, and a simple slab can become a winter project, so budget for erosion control and a dry window for the pour. That’s why the house is built indoors at the factory and why the foundation crew watches the forecast. Lakes, wetlands, and shoreline overlays are common, so tell us if you know your lot has one.
Models that fit Olympia
Wolf doesn’t sell HUD (the federal standard for manufactured homes) manufactured homes.
- Model K (~432 sq ft). A one-bedroom layout to explore for family, guests or a rental. A tight in-town lot still needs review of its buildable area and delivery route before we know which homes could work.
- Model E (~616 sq ft). A flexible two-bedroom on a 14×44 footprint when coverage and delivery work. Model F is the open-plan version.
- Model L (~984 sq ft). A larger cottage with two bedrooms, two baths, a porch, and dining space, when the zone and the truck allow a wider home. It’s under the 1,000-square-foot size allowance protected by state law, but confirm how Olympia measures.
Setbacks follow the zone, and zones differ. Infill Design District compatibility can affect siding and roof choices even when the size is fine.
Utilities: city sewer or county septic
Inside the city, you’re usually on sewer, which still means checking lateral length and cleanout location. Cross into Thurston County and septic capacity often decides the project. County Health review, drainfield expansion, and whether a second dwelling is feasible at all are first-week questions. Thurston County writes its own rural ADU rules, so we confirm them against current code for county parcels.
Lacey and Tumwater have different stormwater requirements and different portals.
Delivery and set day
Delivery runs north on I-5 from our factory in Battle Ground, near Vancouver, WA, past Centralia and into the capital. Compared with Everett or Bellingham, the freeway is the easy part. A wooded west-side driveway with a fir in the only swing path is harder. A 12-foot Model K and a 28-foot-wide Model L need very different trucks and access. The L is a dual-wide, full small house, and we only recommend it when the lot and the street can take it. On a 50-foot lot, that takes careful measuring.
Set day still depends on the forecast. We take Olympia projects when the jurisdiction is clear and the truck has room to work. Olympia is closer than Bellingham for warranty visits and farther than Vancouver. See our warranty page for details.
How people use these homes
Olympia owners build for family space without leaving a neighborhood they like, a separate home for parents, housing for adult children, long-term rentals, or guests. We hear from a lot of state workers who want a parent close by, owners near Evergreen who want a rental, and South Capitol owners who want to downsize without moving. Owner-occupancy requirements are gone inside the UGA under HB 1337. Short-term rental near the capitol is a local, and sometimes political, question, so confirm it before you plan around it.
If it has a kitchen and bath, a “tiny home” and an ADU are the same dwelling for permit purposes.
What comes up in Olympia evaluations
The question is rarely whether ADUs are allowed; inside the UGA, they are, with local rules on top. The real questions are whether the west-side trees have to come down, whether the Infill Design District will accept a shed roof, whether a Model L fits on a 50-foot lot, and whether the county line is 400 feet north of the mailbox. We’d rather sort that out on the evaluation than in week eight of SmartGov comments.
Nearby cities
Lacey and Tumwater border Olympia and each run their own permit counters, stormwater rules, and portals, so a lot that’s “greater Olympia” on a real-estate map may file somewhere else entirely. Centralia is farther down I-5 in Lewis County. Shelton and Harstine Island are in Mason County, with a different ADU guide and a different reviewer. If your lot turns out to be in one of those places, we evaluate it under that jurisdiction’s rules instead.
What to send
An address is enough to start. It helps to include a survey if you have one, the square footage of the existing house, photos of the backyard and the street approach (especially a wooded driveway on the west side), and whether the use is family, long-term rental, or guests. If you’ve already talked to a CPD planner or pulled a stock-plan checklist, send your notes, since they tell us which overlay and drainage questions have already come up.
Cost and time
Permit review, site conditions, and inspection availability set the schedule. Factory production can overlap with site work, but site preparation and utilities still have a big effect on the total. Start with a property evaluation, and see financing if you plan to use a loan or home equity.
What the evaluation looks at
- City of Olympia, Thurston County, Lacey, or Tumwater.
- Zone, Infill Design District, and historic overlay.
- Wetlands, shoreline, and drainage.
- Water and sewer, or septic (county Health if septic).
- The truck route from I-5 to the curb, the crane path, and the 3-foot walkway.
- Your intended use and which model can be delivered.
Send the address. Tell us if you think you’re in the county or if you have a wooded driveway, and we’ll flag any crane problems early, before you commit to a Model L that can’t make the turn.
