Plat of survey: cost, how to get one, and licensed surveyors near me

A plat of survey is the drawing that comes out of an actual field survey of your individual lot. The Village of Villa Park, Illinois puts it about as plainly as any government office does: a plat of survey is "a drawing that represents a property that has been surveyed in the field and certified by an Illinois licensed land surveyor." The two halves of that sentence are what you are paying for. Someone physically went to the property, found or set the corner monuments, and measured. Then a licensed professional put a seal and signature on the result, which is what makes it evidence rather than a sketch.

A typical plat shows the boundary lines with their record and measured dimensions, the location of the house and any garage, shed, deck or pool, driveways and walks, fences and where they sit relative to the line, recorded easements crossing the parcel, building setback lines, and any encroachment either direction across the boundary. It carries the legal description, a north arrow, a scale, the surveyor's seal and the date of the field work. That date matters more than people expect, and it is covered further down this page.

The vocabulary is regional, and that trips people up when they move or when they read advice written for another state. "Plat of survey" is standard usage in Illinois, especially across Cook, DuPage, Lake, Will and Kane counties, where municipal permit desks ask for one by that exact name. In Texas, Florida or the Carolinas the same deliverable is usually ordered as a boundary survey; on the East Coast you may hear location survey or house location plat. If a permit counter, lender or attorney asks for a plat of survey and you are outside Illinois, ask a local surveyor for a boundary survey showing improvements, which is the same product under a different label.

In Illinois only a Professional Land Surveyor licensed in Illinois can certify a boundary and seal a plat of survey. Licensure does not cross state lines, so a seal from a surveyor registered elsewhere is not valid for an Illinois parcel, and the reverse is equally true. If you are not sure how to confirm a surveyor holds a current license in your state, our guide to verifying a land surveyor license walks through the state board lookups.

The most expensive assumption homeowners make is that a plat of survey never expires. As a piece of evidence it does not go stale on a schedule, but the permit counter is a different question entirely, and that is where people lose two weeks of a project timeline. Unincorporated Cook County, Illinois is the clearest published example. Its Department of Building and Zoning requires, for a fence permit, "a Plat of Survey signed and sealed by an Illinois registered surveyor that is not more than five (5) years old." A perfectly valid plat sealed six years ago is simply not accepted, no matter how accurate it still is.

The same requirement carries a second condition that surprises people even more: the plat has to be marked up to show the proposed work. Cook County asks the applicant to indicate on the survey the exact location of the fence, the height from grade to the top of the fence, its length, the material (cedar, chain-link, vinyl and so on), and the location, size and swing direction of any gate. It also asks for a statement that the finished side will face out, with poles, supports and braces on the owner's side, and a statement whether the fence encloses a swimming pool or any body of water deeper than 24 inches, in which case gates must be self-latching and swing out. Post holes must be dug to 42 inches. In residential districts the fence may reach 6 feet along a common lot line but only 3 feet in front yards and corner side yard setback zones; in commercial and industrial districts those figures are 10 feet and 3 feet.

So the practical test is not "do I have a plat" but "do I have a plat that is recent enough, and does it show what I am about to build." Both halves have to be true. Where the drawing is recent but does not depict the project, a surveyor can often add the proposed work to the existing plat cheaply rather than resurveying. Where the plat predates improvements that already exist, an addition, a new garage, a pool, a replaced fence, it no longer represents the property and a reviewer is entitled to reject it on those grounds alone.

Rules vary by jurisdiction, and the five year figure is Cook County's, not a national standard. Some municipalities accept any plat that accurately reflects current conditions; others set their own window. Call the permit desk and ask two questions before you order anything: how recent the plat must be, and what the plat must show. Ten minutes on the phone routinely saves several hundred dollars and a rejected application. If your project is a fence specifically, our survey for a fence page covers what departments ask for, and for permit drawings generally see the site plan survey for a building permit.