Topographic survey: the base plan for building, grading and drainage

A topographic survey records the shape of your land and what stands on it: elevations, slopes, buildings, trees, driveways, utilities and drainage features. Architects, designers, engineers and builders use it as the base plan for their work.

What it includes

• Elevations and contour lines, tied to a geodetic datum or a local benchmark;
• existing buildings, decks, retaining walls, fences and paved areas;
• trees, often with their trunk diameter where a tree protection by-law applies;
• visible utilities and drainage features: catch basins, ditches, culverts, swales;
• the property lines, when the topographic survey is combined with a boundary survey.

When it is needed

• Designing a new house, an addition, a garden suite or a laneway home, especially on a sloped or irregular lot.
• Applying for a building or site plan permit: many municipalities ask for existing and proposed grades.
• Planning grading, a driveway, a retaining wall or a pool.
• Solving drainage problems, such as water flowing towards the house or to a neighbour's lot.

How to brief the surveyor

1. Ask your designer or engineer for the list of items they need and share it with the surveyor.
2. Say how far to survey beyond your lot: the street, the boulevard, the neighbouring grades.
3. Decide whether the boundaries must be shown: a topographic survey alone does not re-establish property lines.
4. Ask for the file format your designer uses (PDF, CAD drawing).

Describe your project in the form: commissioned land surveyors near you get back to you with a written quote for your topographic survey.