Municipality
Guide to Lot Drainage
City of Calgary
2019 edition, read by the research. A cold-climate Canadian city guide used for comparison.
Open the source- Consulted
- October 10, 2026
- Region
- CA
- Language
- en
Cited by
Guides
What we take from it
- Downspouts extend 1.2 to 1.8 m and discharge onto lawn, not onto driveways or walks.
- The Calgary guide asks for at least 4% over 1.2 m next to the foundation and at least 2% for lawns and swales.
- The Calgary guide keeps downspout outlets at least 2 m from public infrastructure.
- Calgary recommends consulting a professional before building a dry well, because topography and soil decide how well it works.
- At least 2% of fall for lawns and swales.
- The Calgary guide extends downspouts 1.2 to 1.8 m, with a splash pad, and discharges onto lawn rather than driveways and walks.
- At least 4% over 1.2 m next to the foundation.
- Outlets at least 2 m from public infrastructure.
- Maximum 33% slope without a wall.
- Slopes, downspouts and swales.
- Calgary requires at least 4% over the first 1.2 m along a foundation, at least 2% in lawns and grassed swales, and no more than 33% without a retaining wall.
- Calgary asks that a swale be deep and wide enough to hold the lot's runoff, with at least a 2% slope when grassed, and notes that neighbours share upkeep of a swale on the property line.
- Lawns typically have 100 to 150 mm of topsoil; a layer of 300 mm or more holds rainwater better.
- Calgary recommends extending downspouts 1.2 to 1.8 m, placing a splash pad at the outlet, discharging onto lawn or planting rather than a driveway or sidewalk, and staying at least 2 m from sidewalks and streets.
- Calgary requires at least 4% over the first 1.2 m along a foundation, at least 2% in lawns, and no more than 33% without a retaining wall.