What a Boundary Survey Actually Is
A boundary survey is a professional determination of a parcel's legal boundaries on the ground. A licensed land surveyor researches the chain of title, examines historical surveys, and uses precision instruments to locate or set property corners. The result is a plat map — a scaled drawing showing the parcel boundaries with exact measurements, bearings, and any encroachments or easements found during the process.
In Washington State, only a licensed Professional Land Surveyor (PLS) can legally establish and certify property boundaries. This isn't a GPS exercise you can do yourself — it requires legal research, field work, and professional judgment to reconcile conflicts between historical records and physical evidence on the ground.
Washington State Law: RCW 58.09 governs surveying practice in Washington. Any survey that establishes or reestablishes property lines must be prepared by a licensed PLS and filed with the county auditor.
When Do You Actually Need a Boundary Survey?
Before Any Construction Near a Property Line
If you're building a fence, addition, outbuilding, or anything that will be within 5–10 feet of where you believe your property line to be, get a survey first. Construction over a property line creates legal liability and can require costly removal. In Washington, encroachment disputes can escalate into adverse possession claims if not resolved promptly.
When Buying or Selling Rural Property
Most residential property transactions in urban areas don't require a new survey — the lender relies on title insurance and existing plat records. But for rural parcels, particularly those described by metes and bounds (rather than a recorded subdivision plat), a current survey is often warranted. Rural parcels in eastern Washington, in particular, may have had no professional survey in decades.
Before Subdividing
Any subdivision — splitting one parcel into two or more — requires a survey as part of the short plat or long plat process. The surveyor prepares both the preliminary and final plat drawings. If you're pursuing subdivision, budget for surveying from the start.
When You Have a Boundary Dispute
If you and a neighbor disagree about where the line runs, a survey by a neutral licensed professional is the authoritative resolution. The survey record becomes the legal document. Note: having "always used" a piece of land, or having a fence in a particular location, doesn't establish legal ownership — but documented adverse possession can, after 10 years in Washington. Don't wait on a boundary dispute.
When Encroachments Are Discovered
A title search sometimes reveals recorded encroachments — situations where a structure from a neighboring parcel sits on your land, or vice versa. Lenders often require a survey to quantify the encroachment before approving financing.
Before Timber Harvest or Large-Scale Excavation
Logging or excavating over a property line onto a neighbor's land is a serious legal matter. Timber trespass in Washington (RCW 64.12.030) allows for treble damages. Know your line before you cut.
What the Survey Process Looks Like
A typical boundary survey in Washington proceeds through these stages:
- Title and record research: The surveyor reviews the deed, plat records, previous surveys, easements, and any available county GIS data. For rural metes-and-bounds parcels, this can take several hours of research.
- Field work: The crew goes to the property to search for existing monuments (iron pins, rebar, concrete markers) and take measurements. GPS and total station instruments are used to establish precise coordinates.
- Calculation and boundary determination: The surveyor synthesizes the field data with the record research to determine the legal boundary. Where conflicts exist between monuments and record descriptions, professional judgment governs — with legal rules of priority (calls to monuments over courses and distances, etc.).
- Setting corners: If corners are missing, the surveyor sets new monuments — typically iron rebar with a plastic cap stamped with the surveyor's license number.
- Plat preparation and filing: The surveyor prepares the final plat drawing and files a Record of Survey with the county auditor. This becomes the official record of the boundary determination.
How to Read a Survey Plat
A boundary survey plat contains more information than most people realize. Here's what to look for:
- Bearings and distances: Each line of the boundary has a bearing (compass direction) and length. "N 45°30' E, 210.00'" means travel north-northeast for 210 feet.
- Monuments: Symbols distinguish found monuments (existing) from set monuments (placed by this surveyor). A circle with a dot typically indicates a found monument; a filled circle indicates set.
- Easements: Recorded easements for utilities, access, or drainage are shown as dashed lines with notes identifying the recording number.
- Encroachments: If a fence, building, or improvement crosses the boundary, it's shown on the plat with a note — often a key finding for buyers or dispute resolution.
- Acreage: Total parcel area, computed from the surveyed dimensions — which may differ slightly from the recorded deed description.
| Parcel Type | Typical Survey Cost (WA) | Typical Timeline |
|---|---|---|
| Residential lot (urban/suburban) | $1,000–$2,500 | 1–3 weeks |
| Rural parcel (5–40 acres) | $2,500–$6,000 | 2–6 weeks |
| Large rural parcel (40+ acres) | $5,000–$15,000+ | 4–12 weeks |
| Complex/dispute resolution | $8,000–$30,000+ | Variable |
What Affects Survey Cost?
Several factors drive variation in survey costs:
- Parcel size and terrain: Larger parcels and rough terrain require more field time.
- Record complexity: Old metes-and-bounds descriptions with ambiguous language require more research and professional judgment to resolve.
- Availability of existing monuments: When previous surveyors have set monuments and they're still in place, the current survey goes faster. When they're missing or disturbed, more work is required.
- Neighboring parcel complexity: A boundary adjoining another complex parcel may require researching that parcel's chain of title too.
- County filing requirements: Some counties have specific plat format requirements that add preparation time.
Practical tip: Get at least two quotes from licensed surveyors. Rates vary significantly across Washington counties, and a surveyor already familiar with neighboring parcels may be substantially faster than one starting fresh.
Boundary Survey vs. ALTA/NSPS Survey
An ALTA/NSPS Land Title Survey is a higher-specification survey typically required for commercial real estate transactions. It includes everything in a boundary survey plus utility locations, zoning setbacks, flood zone determination, and a Table A checklist of optional items requested by the lender or title company. For residential and rural Washington properties, a standard boundary survey is almost always what's needed.
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Explore Boundary Survey Services →Frequently Asked Questions
Can I just use the county GIS parcel layer?
No. County GIS parcel data is approximate — it's compiled from deeds, old surveys, and administrative records with varying accuracy. It's useful for reference, but it has no legal standing and can be off by 10–100+ feet in rural areas. A licensed survey establishes the legal boundary.
Do I need a survey to get a building permit?
Often yes, particularly for structures near setback lines. Most Washington counties require a site plan showing building location relative to property lines. For anything close to the line, the county may require a setback certification from a licensed surveyor.
How long is a survey valid?
A survey establishes boundaries at a point in time based on the legal record. The underlying legal description doesn't change, but conditions on the ground do — neighbors build, fence lines shift, monuments get disturbed. For any significant decision — construction, sale, subdivision — a survey more than 10–15 years old should be reviewed for continued accuracy.