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Lot Grading Requirements

Minimum recommended slopes

A sloped surface is required to effectively drain water away from the foundation walls, including areas under steps and decks.

  • Soft surfaces (including pervious gravel, clay, topsoil, sod, crushed rock or wood chips) should have a minimum five percent positive slope in the area 3m (10 ft) around your foundation
  • For soft surfaced areas with less than 3m (10ft) between foundation and property line (side yards), a minimum drop of 15cm (six inches) is recommended
  • Hard surfaces (including impervious concrete, asphalt, or brick pavers) should have a minimum 0.75 percent positive slope in the area 3m (10 ft) around your foundation
  • For hard surfaced areas with less than 3m (10ft) between foundation and property line (side yards), a minimum drop of 2.5cm (one inch) is recommended

Use a carpenter’s level and a tape measure to quickly and easily determine the slope around your foundation

 

Drainage swales

Drainage swales are shallow, sloped, linear depressions which convey surface water runoff toward a city street or lane, and are constructed along rear and side property lines.

Shared Drainage Swale

  • Side property line swales should have a minimum slope of two percent for grass, clay or decorative rock surface, or 0.75 percent for a hard surface such as concrete, asphalt or paving stones
  • Shared drainage swales are located between adjacent properties along the shared property line and should be a minimum of 30 cm (12 inches) in width with a minimum of 15 cm (six inches) on each side of the shared property line

See examples of a Side Property Line Swale and a Shared Side Property Line Swale

  • Rear property line swales must be sloped to match the rear property line design elevations indicated on the lot grading plan

See examples of a Standard Rear Property Line Swale and a 'Back to Front Drainage' Rear Property Line Swale
 

Concrete swales

Some lots have concrete swales that were constructed by the developer located along side or rear property lines to facilitate drainage to the street or the storm sewer catch basin. Rear property line concrete swales are located in utility easements located along the rear property line. It is the homebuilder’s or homeowner’s responsibility to ensure that concrete drainage swales are not damaged during construction and are not buried or impeded in any way.

See examples of a Side Property Line Concrete Swale and a Rear Property Line Concrete Swale
 

Downspouts

When planning downspout locations and the direction of discharge, consideration must be given to lot drainage styles and neighbouring properties. It is recommended that homebuilders and homeowners consult with their neighbours to determine downspout locations and direction of discharge.

Downspouts should be:

  • Extended at least 2 m (six feet) from any foundation
  • No higher than 0.6 m (two feet) from the ground
  • Extended no closer than 3 m (10 feet) from any property line
  • Discharged onto drainage swales which drain to the street or rear property line
  • Discharged onto a permeable surface such as a lawn or garden area
  • Discharged to an area that will not adversely affect their property or any neighbouring property

Downspouts SHOULD NOT discharge or drain directly onto neighbouring properties, city sidewalks, walkways, streets, back lanes or parks

 

Sump discharge

When planning sump discharge locations and direction of discharge, consideration must be given to the drainage style of the lot. For example, it is recommended to discharge in front of the home when the lot drainage style is back to front (Type A). It is recommended that homebuilders and homeowners consult with their neighbours to determine discharge locations and the direction of discharge to help avoid adverse impacts to their property or their neighbour’s property.

See an example of a sump discharge assembly

Sump discharge should be:

  • Extended at least 2 m (six feet) away from any foundation
  • Extended no closer than 3 m (10 feet) from any property line
  • Discharged onto a permeable surface such as a lawn or garden area
  • Discharged to an area that will not adversely affect their property or any neighbouring property

Sump pumps SHOULD NOT discharge or drain directly onto neighbouring properties, city sidewalks, walkways, streets, back lanes or parks