During heavy rain, the sewers can become overloaded. This increases pressure on the sewer systems and overland drainage routes, such as roads, local rivers and streams, which can lead to lead to basement flooding.

The City’s Basement Flooding Protection Program is a multi-year program that is helping to reduce the risk of flooding by making improvements to the sewer system and overland drainage routes. Projects are taking place in basement flooding study areas across the city.

Enter your address in the interactive map to see what projects are taking place near you. View the Map

For each basement flooding study area, an Environmental Assessment (EA) study is conducted.  These are complex studies that can take two or more years to complete. EA studies:

  • Examine the  sewer system and above ground areas.
  • Make recommendations to reduce the risk of flooding.

Improvements may include building:

  • Storm sewer tunnels.
  • Underground and above ground storage facilities.
  • Additional or larger storm or sanitary sewers.
  • Inlet control devices (to slow the drain of rain into the sewer system).
  • Additional catch basins (square grates on the side of the road) in low lying areas.
  • Sealing sanitary manhole covers.
  • Once an EA study is complete, the recommended basement flooding projects are sequenced into a 5-year project list which is presented on an annual basis to City Council.
  • Projects are prioritized and scheduled to protect the greatest number of properties as soon as possible, within approved budgets and coordinated with other construction work — as per Council approved criteria.
  • The length and type of construction will vary depending on the type of projects being implemented.

There are several stages of work that must be undertaken before a construction project is completed:

  1. Preliminary Design: Preliminary engineering drawings are developed for review and input from City departments, utilities and regulatory authorities. The input is incorporated in the overall design.
  2. Detailed Design: Final detailed engineering drawings are developed and permits to proceed with the construction work are obtained. Prior to construction, Public Notices are delivered door-to-door about two months in advance to let the community know that a construction project will soon be taking place.
  3. Construction: Construction Notices are delivered door-to-door about two weeks in advance and road signage is placed in the community to provide residents with project details prior to the start of construction. Construction activities may include excavation of the roadway, sidewalks and/or boulevards, and may require protective fencing to be erected.
  4. Restoration: Restoration within construction areas varies by project, and typically involves restoration of road surfaces, sidewalks, grass and tree plantings, etc.

The City and its contractors are committed to communicating with local communities about basement flooding construction activities and anticipated disruptions in their neighbourhood.

The Basement Flooding Protection Program has a Field Ambassador who is dedicated to communicating with the local community and the on-site contractor, and responding to construction inquiries during the course of the project.

You may spot the Field Ambassador on your street in a brightly coloured blue vest.

Field Ambassador contact information is provided in the Construction Notice for each project – available on the City’s Construction Information website.

Rain and groundwater that improperly enters the sanitary sewer system is called inflow and infiltration (I/I) and can contribute to basement flooding. The City’s conducting a pilot study to help find and address I/I issues. Watch the video below to learn more.