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Phase 1 · Site facts · Step 1.1

Boundary + topographic survey

A WA-licensed surveyor sets the legal lot lines, captures grade, marks visible utilities, and inventories every regulated tree with its drip line. Everything downstream lives on top of these lines.

Who
Surveyor
How long
2-3 weeks
Cost
$3,500-$6,000
You end up with
Stamped survey accepted by SDCI and SPU

If you skip this: SDCI and SPU only accept stamped surveys. Assessor maps and title sketches won't substitute — and fences in Seattle are commonly two to three feet off the real line.

If this is your first time hiring a land surveyor, the price tag can feel steep for what looks like a tripod and a couple of stakes. Here's what you're actually buying — and why almost every downstream step depends on it.

What you're paying for

Two deliverables, usually bundled:

  • Boundary survey — the legal lot lines with monumentation (the brass caps or rebar that mark the corners). The Seattle Department of Construction and Inspections (SDCI) and Seattle Public Utilities (SPU) won't accept assessor maps, title-company sketches, or "old plat" data. Only a stamped survey by a Washington-licensed land surveyor (a PLS — Professional Land Surveyor).
  • Topographic survey — grade contours, visible utilities, easements, and (per Seattle's tree code) every regulated tree with species, diameter, and drip line.

Combined cost in Seattle: $3,500 – $6,000 for a typical SF lot.

Why this comes first

Almost everything downstream depends on the survey:

  • The architect can't draw a real site plan without grade and the legal property line.
  • The arborist's tree inventory gets recorded onto the survey.
  • The geotechnical engineer needs grade contours.
  • SDCI plan review requires it on the permit submittal.

Skip topo and just do boundary, you save maybe $1,500 — and pay it back twice when the foundation has to get redesigned around grade reality.

Where to find a land surveyor

Three reliable channels, in order of how the founder would actually shop:

  1. Your designer's referrals. Designers carry 2–3 surveyors they've worked with on similar projects. Ask first — the existing relationship smooths scheduling and saves you from explaining the SDCI tree-code requirement to a new firm.
  2. WA DOL professional license search. Verify a license lets you filter by Professional Land Surveyor (PLS) and search by city.
  3. Recent permit history. The SDCI Permit and Site History Research Tool — the surveyor of record on recent DADU permits in your neighborhood is a local specialist who already knows the SMC 25.11 tree-inventory format.

What to look for: active PLS license; recent Seattle DADU work (commercial-only firms charge more and don't always include the tree inventory); written quote with deliverables clearly enumerated.

How to hire a surveyor

  1. Verify the PLS license at WA DOL — Engineer & Land Surveyor Search.
  2. Get two or three quotes. Pricing in Seattle is fairly tight.
  3. Confirm in writing that the deliverable includes the regulated trees per current SMC 25.11 (species, DSH at 4.5 ft, drip line for each tree ≥ 6 inches DSH).

What the deliverable looks like

You'll get a stamped PDF (and usually CAD files for the architect) showing the legal lot, monumentation found or set, contours at typically 1-ft intervals, visible utilities, easements of record, and the regulated tree inventory.

Hand it to the architect, the arborist, and the geotech together. From here on, every decision lives on top of these lines.

Where this information came from

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