Seaside is the Promenade, the Necanicum River, and a street grid that fills with visitors in July. Building here isn’t like building on Astoria’s hills or under Cannon Beach’s design overlay. Lots are often small and close to the neighbors. Many are sandy or sit on a high water table, which means groundwater close to the surface.
A detached cottage can be family housing, a long-term rental, or a guest space behind a house that already sees summer traffic. Short-term rentals are regulated locally. So we start with a simpler question: can the lot take a dwelling at all?
We build the home in our factory. Delivery to Seaside runs on US-26, the Sunset Highway west from the Portland metro. For Astoria, we use the US-30 river route instead. It’s a long haul over the Coast Range, though shorter than the run to Florence. Set day is the day the home is placed on its foundation, and on the coast the weather still decides when it happens.
Who reviews your lot: Seaside or Clatsop County
Depending on the site, you file with the City of Seaside Building Department. If the property is outside city limits, you file with Clatsop County instead. A Gearhart or unincorporated address with a Seaside mailing city doesn’t go through City Hall. (Unincorporated means it’s outside any city.) That’s why we pull the parcel record before anyone sketches a backyard.
Inside the city, the planning department handles zoning, height, lot coverage, and ADU rules. Seaside’s zoning map and ADU information run through planning. Each district has its own setbacks, which are the distances a building has to sit from the property lines. We check the zone on your lot.
Outside the city, Clatsop County building and land-use rules apply. Our Clatsop County ADU guide explains what to check: zoning designation, septic vs sewer, slope, and access.
Statewide, Oregon requires cities over 2,500 people inside a UGB to allow at least one ADU on lots zoned for detached single-family homes (ORS 197A.425). A UGB, or urban growth boundary, is the line that marks where a city can grow. HB 2001 bars owner-occupancy and extra off-street parking mandates for long-term units in the cities it covers. Seaside still sets siting and design standards. Our Oregon ADU rules guide covers the statewide rules.
A second building may be classified as an accessory dwelling unit, a guest house, or a detached residential unit. The classification affects setbacks, utilities, and design standards. Tell us whether the home is for family, guests, or a renter, so the permit application matches how it will be used.
HUD (the federal standard for manufactured homes) manufactured homes fall under a different code. Wolf builds modular homes, inspected by the state under Oregon’s prefabricated-structures program. The Seaside Building Department won’t approve a park model or a trailer as an ADU.
How a Seaside permit works
The city path usually looks like this:
- Confirm who reviews it: the City of Seaside Building Department or Clatsop County Building Codes.
- Review the zone and the city’s current ADU handout. Lot coverage and height are set locally.
- Prepare a site plan. It shows property lines, the planned foundation, utilities, and the access route for installation. Modular units must meet Oregon’s residential code and carry the state insignia, and the city still reviews placement.
- Submit through the Seaside Building Department’s online portal, or in person at City Hall. County applications follow the county’s process.
- Pass inspections for the foundation, utilities, and final placement. Occupancy follows once inspections pass.
Several permits come up on these jobs. They include attached or detached ADU, guest house, accessory structure, mechanical, electrical, plumbing, septic, propane, critical areas, and engineered stormwater. Many also need water adequacy verification (WAVE). WAVE matters on the coast, where you have to show an adequate water supply instead of assuming one.
Our team handles engineering and permitting support. That way, you don’t have to coordinate a designer in Portland with a setter who has never worked on Broadway in August. Incomplete drawings, stormwater comments, and critical-area comments all add review cycles. Each extra cycle adds time, and that’s how a simple cottage slides into a winter project.
Seaside lots we see
- West of US-101, toward the Promenade. Tight lots, often with older cottages. Parking competes with a crane, and you’ll find sand and a high water table. A 12-foot-wide Model K is much easier to place here than a 14-foot Model F.
- East of the highway, toward the hills and the golf-course side of town. Lots can be larger, with more trees, more grade, and less sand. The truck path can be better. It can also be worse, if the street is a dead end with no turnaround.
- Near the Necanicum. Expect river, drainage, and flood overlay questions. The river’s forks and side channels create flood-overlay pockets that don’t follow a simple west-is-wet, east-is-dry pattern. We check the flood map for your parcel.
- South toward Gearhart, and north toward the estuary. Jurisdiction lines shift here, so we confirm the city limit. A “Seaside” real-estate listing doesn’t tell you who reviews the lot, and unincorporated county land is close by.
Coastal wind and salt are constant. The factory keeps the house out of the rain while it’s built. On the lot, drainage is the issue people tend to underestimate. Sandy soil can look like it drains well until the winter water table rises into the excavation. Erosion control and a legal stormwater path are real cost items.
Tsunami inundation zones are mapped on this coast. These are the areas a tsunami could flood. A lot on the flats may sit in an overlay that doesn’t prevent a dwelling. It can still affect foundation design, utilities, and insurance. We check it for your lot.
Models that fit here
- Model K (~432 sq ft). One-bedroom coastal living for a guest, a parent, or a long-term renter.
- Model F (~616 sq ft). Two bedrooms, when the lot can take the width and the coverage.
Some local rules tie ADU size to the main house’s living area. If the house is small, that can cap you below the catalog size. Measure the house before you pick a model.
Family, long-term rental, or vacation rental
People add units in Seaside for aging parents and adult children. Some want a quieter guest cottage behind a house that already rents. Others want long-term housing in a town that doesn’t have enough of it.
Many inquiries start with vacation-rental income. Short-term rental licensing, parking, and any owner-occupancy rules for lodging are set locally, and they change over time. HB 2001’s parking and owner-occupancy protections apply to long-term ADUs. They don’t create a lodging license, and the ADU permit doesn’t include one.
Seaside also has people working in the hotels, the hospital, and the shops who can’t find a year-round place to live. Permitting treats a Model K rented to a 12-month tenant differently than a weekend short-term rental. The long-term file is usually simpler.
Browse our case studies for finished coastal projects, including a vacation home in Yachats.
Delivery on US-26, then the last few blocks
From our factory in Battle Ground, just north of Portland, the route runs through the Portland metro. Then it heads west on US-26 over the Coast Range to Seaside. Expect metro traffic first, then rain, fog, and a two-lane highway that backs up on nice beach days. Escorts and the set-day schedule have to account for all of it. Astoria’s US-30 route follows the Columbia and gets river wind. Route 26 runs through wet timber country.
Summer traffic on 26 and 101 is heavy. A set day on a street near the Promenade in August means parked cars, pedestrians, overhead lines, and sand in the crane mats. A crane on a Saturday in August also disrupts the whole block. We prefer a weekday in the shoulder season, and we schedule around weekends like Hood to Coast.
The last six blocks usually decide the model. A module that travels fine on the highway may not fit a 1920s street with a spruce tree and a low service drop. That’s the overhead power line into a house. That’s why we check access in the first week.
Once the module is on the pad, the site crew makes the tie-ins and seals the home against weather the same day. Then they connect mechanical and plumbing. A two-piece home adds a marriage day, when the crew joins the two halves. Sand getting into connections is a common problem in Seaside, and we plan for it.
Utilities and water adequacy
Most Seaside lots in town are on city water and sewer. That still leaves the length of the service line, finding the cleanout, and whether the electrical service can support a second dwelling. WAVE shows up in the permit list for a reason.
Outside city limits, you may be on a well and septic. Then Clatsop County’s onsite program controls part of the schedule. Septic capacity is often what rules out a second dwelling there.
Cost
Site work, drainage, electrical upgrades, and crane access on sandy ground can all change the total project cost. Building in the factory makes the home price more predictable than building on site in the rain. Local permit and utility charges still apply. If you plan to combine a HELOC (home equity line of credit) with a construction loan, see financing.
Warranty visits on the coast
Seaside is a long drive from the factory. That’s true for the delivery and for every punch-list and warranty visit after it. The same crews handle warranty work, and a January visit gets scheduled around coastal storms. Your home comes with a one-year warranty, and we stand behind our workmanship for years afterward.
The site work also follows the coastal weather. Foundations and trenches depend on how saturated the sand is, whatever the factory calendar says.
What the evaluation covers
Send the address, where the building would sit, and any survey. The free property evaluation is our first look. It covers:
- City vs Clatsop County.
- Zone, setbacks, coverage, and height under the city or county code.
- Flood and tsunami overlays on your parcel.
- How you plan to use it: family, long-term rental, or short-term.
As the project moves forward, we work through the site itself:
- Soils, drainage, and water table.
- Water, sewer or septic, WAVE if it applies, and electrical.
- The truck path off US-26 and US-101 to the curb, then to the pad.
Send the address. We’ll start with zoning, setbacks, and overlays, and point you to the model sizes that may fit. If you’re outside city limits, mention it. The county is a different reviewer than Seaside City Hall.
Nearby towns
Cannon Beach has its own design overlay. Astoria is a hillside river city with ePermitting and a Design Review Commission. Warrenton has its own city hall. Tillamook is a bay-and-dairy county seat an hour south on 101.
