A land survey is a scaled drawing, signed and sealed by a licensed land surveyor, that shows a property's legal boundary and what sits on and around it. To read one, start with the legal description, then check the bearing and distance on each boundary line, the monument at each corner, and every easement, setback, and encroachment shown on the sheet.

You do not need to be a surveyor to read one well enough to spot a problem. Most of the surprises that cost money later, like a fence over the line or an easement under the spot where you planned a garage, are on the drawing if you know where to look.

Diagram of a boundary survey A rectangular lot with a bearing and distance on each line, iron rod monuments at the corners, a 10-foot utility easement along the north line, building setback lines, a fence that encroaches over the east line, a north arrow, and a scale bar. 10' utility easement (Doc. No. 123456) Building setback lines Fence 1.4' over line Iron rod found Iron rod set N 89°45'12" E 150.00' S 89°45'12" W 150.00' (M) 150.10' (R) N 00°14'48" W 100.00' S 00°14'48" E 100.00' N 040 ft Illustration, not a real survey

Swipe to see the whole drawing.

The parts of a boundary survey covered below. Real surveys add a title block, legend, legal description, and the surveyor's seal.

Which kind of survey do you have?

The word "survey" covers several documents. Check the title before you read anything else, because each one answers a different question.

  • Boundary survey. Locates the property lines and corners on the ground. This is the one to use before placing a fence, an addition, or a new building.
  • ALTA/NSPS land title survey. The most detailed type, built to a national standard. Common on commercial purchases and loans, and it ties every easement to the title report.
  • Topographic survey. Shows existing ground elevations, contours, trees, and utilities. It is the base layer an engineer builds a site plan and grading plan on.
  • Plat. A drawing recorded with the county that creates lots, like a subdivision plat. A survey usually cites the plat your lot came from.
  • Lighter lender documents. Some lenders accept less than a full survey. In Colorado this is often an Improvement Location Certificate, which says on its face that it cannot be used to set property lines. Do not place a fence or building off one.

The title block and legal description

The title block names the surveyor, their license number, the date of the fieldwork, and the county. A boundary survey is not complete without the surveyor's signature and seal.

The legal description is the written version of the boundary. It comes in one of three forms:

  • Lot and block. "Lot 4, Block 2, Prairie View Addition." The lot is defined by a recorded plat.
  • Metes and bounds. A walk around the boundary, line by line, using bearings and distances from a starting point.
  • Section, township, and range. The federal grid used across most of Minnesota, Colorado, North Dakota, and Utah, common on rural land.

Boundary lines: bearings and distances

Each boundary line carries two labels: a bearing (its direction) and a distance (its length).

A bearing like N 89°45'12" E reads as: face north, then turn 89 degrees, 45 minutes, 12 seconds toward east. That line points almost due east. The first letter is always N or S. The last is always E or W. The distance, like 150.00', is in feet to the hundredth.

Curved lines list a radius, an arc length, and a central angle (often marked Δ or "delta") instead of one bearing.

Watch for (M) and (R). M is what the surveyor measured. R is the record value from the deed or plat. A small difference is normal. A large one deserves a question to the surveyor before you build near that line.

Monuments: the corners on the ground

Monuments are the physical markers at each corner, usually an iron rod or pipe, often with a plastic cap stamped with a surveyor's license number.

  • Found means the surveyor located a marker that was already there.
  • Set means the surveyor placed a new one.

Symbols vary by surveyor, so read the legend. A filled circle for found and an open circle for set is common but not universal.

Easements, setbacks, and encroachments

These three are where most problems hide.

  • Easements give someone else a right to use part of your land: utility lines, drainage, or access. They show as dashed strips with a width and a recording reference, like a document number. You generally cannot build a structure inside one.
  • Setbacks are the minimum distances from each line that zoning requires. Some surveys draw them; others do not, so confirm with the city's zoning code.
  • Encroachments are things that cross a line: a fence, a shed, a driveway, or a roof overhang. The survey notes them with a distance, like "fence 1.4' over line." They run both ways, so check for your improvements on the neighbor's land too.

Elevations and flood information

A topographic survey adds contours, spot elevations, and a benchmark. The benchmark note names the vertical datum, usually NAVD 88, so every elevation on the sheet ties to the same reference.

Most surveys also carry a flood note: the FEMA flood zone, the map panel number, and its effective date. Zone X is generally outside the 1% annual chance floodplain. Zones A and AE are inside it, which brings insurance requirements and extra permit review.

Six checks before you buy or build

  1. The date. Anything built after the fieldwork date will not be on it.
  2. The seal and signature. No seal, no boundary survey.
  3. Measured vs record. Look for large gaps between (M) and (R).
  4. Easements under your plans. Sketch where the house, garage, or addition would go and see what it lands on.
  5. Encroachments. In both directions.
  6. The flood note. Zone and panel date.

When an engineer needs your survey

Before a site plan or grading plan can start, the engineer needs a boundary survey and usually a topographic survey. Every line on the design is drawn on top of it.

Land Pro Civil does not do surveying. We work alongside licensed land surveyors and can recommend ones we have worked with. If you have a survey and are planning to build, send it over and Paul will tell you what it means for the project.