Plat Maps and Legal Descriptions, Explained for Buyers
Your deed doesn't say '123 Maple St' — it cites a lot, block, and plat, or runs metes and bounds. How to read the documents that define what you own.
The address on the listing is for mail carriers. What you actually buy is defined by the legal description on the deed — and in the Seattle area that’s usually a citation like “Lot 7, Block 3, Maple Grove Addition, according to the plat thereof recorded in Volume…, records of King County.” Understanding that one sentence — and the plat map it points to — turns several mysteries of your transaction into plain reading.
What a plat is
When land is subdivided, the developer records a plat: a surveyed map dividing the parcel into numbered lots and blocks, fixing street layouts, and frequently dedicating easements and tracts in the same stroke. Once recorded, the plat becomes the reference document — every later deed just points at it. Seattle’s older neighborhoods are quilts of these “Additions,” many platted a century-plus ago, which is why your legal description may name a developer who died before your grandparents were born.
The plat is worth actually looking at (county records make this reasonably easy online, and your title officer will happily pull it), because it shows things the listing never will: platted easements along the rear lot line, alley dedications, odd lot shapes hidden by fences, and the original lot pattern under what’s now a single yard.
Lot-and-block vs. metes and bounds
City lots mostly enjoy the tidy lot-and-block form above. Outside platted areas — acreage, older rural parcels, odd remainders — descriptions run metes and bounds: a written walking tour of the boundary (“thence north 200 feet…”), often anchored to the federal section-township-range grid. Metes-and-bounds parcels aren’t worse, but they’re where description errors and ambiguities live, and where a survey earns its keep — the prose has to be translated to the ground by a professional, not by pacing the fence line.
Why buyers should care, concretely
- The “unit lot” pattern. Much of Seattle’s townhome stock sits on unit lot subdivisions — small platted lots under each home. The plat explains what’s exclusively yours versus shared access tracts, which is half the answer to the townhome-HOA question.
- Easements appear here first. Platted utility and access easements show up as dashed lines on the map years before they show up as Schedule B exceptions.
- “What the seller owns” surprises. Two original lots sold as one yard (tax and development implications), or a tract letter that turns out to be a shared driveway the HOA owns — plat reading catches both.
- Errors propagate. A digit wrong in the volume number, a lot transposed — description typos are classic clouds on title, usually fixed by corrective deed, occasionally by worse. The title commitment’s description should match the purchase agreement’s; thirty seconds of comparison is free insurance.
The honest take
Nobody falls in love with a plat map. But it’s the rare transaction document that’s a picture, and five minutes with it answers questions buyers otherwise carry as vague anxieties: where the lot really ends, what that gravel strip is, why the neighbor parks there. Read the legal description, glance at the plat, ask the title officer about anything dashed, lettered, or weird. That’s the whole skill.
It’s also a fair test of an agent: the ones who can walk you through a plat without bluffing are showing you what their fee buys. Compare those fees side by side when Manaky Homes launches — free, on the waitlist now.