What are the surface grading requirements around a house in Ontario?
The ground around a building must be graded so surface water drains away from the foundation and does not accumulate against it or flow toward neighbouring buildings. Downspouts must discharge so water is carried away from the wall, without causing erosion or soil gas entry paths.
Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.
Grading is where good foundations get undermined, literally. A positive slope away from the wall, commonly around 2 percent or more for the first couple of metres in municipal lot grading standards, keeps roof and surface water from loading the weeping tile. Typical failures include settled backfill creating a moat at the foundation, landscaping or hardscape reversing the original grading plan, and downspouts dumping at the wall. Most Ontario municipalities enforce an approved lot grading plan on new builds, and final grading certification is often a condition of releasing security deposits.
Your yard should slope away from the house on all sides so rain runs off instead of pooling at the basement wall, and downspouts should shoot water well clear of the foundation. Watch for soil settling near the wall over the first few years and top it up.
Get answers like this for any code question
BUILDAiD Assist searches the building code and answers in plain English with exact citations — in seconds.
This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.