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Causes of basement flooding:

• A leak in your home’s foundation, basement walls, or basement windows or door.
• Poor lot drainage.
• Failure of the weeping tile system (foundation drains).
• Overflowing eavestroughs.
• Leaking/plugged downspouts.
• A blocked connection between your home and the main sewer in the street.
• A back-up of wastewater in the sewer system (or a combination of wastewater and rainwater. from the sanitary or combined sewer system).
• Failure of a sump pump (in some areas) used to pump weeping tile water.

There are three types of sewers in Toronto

• Sanitary sewer: The sanitary sewer, which carries wastewater (sewage) is connected to your home’s plumbing fixtures (toilets, sinks, laundry, etc.) and leads to a sewage treatment plant.
  • Partially Separated Sanitary Sewers: In the past, foundation drains (e.g. weeping tiles) from houses were allowed to connect to sanitary sewers under previous municipal sewer bylaws. In areas originally serviced by combined sewers, foundation drains are still connected to the combined sewers after the City installed storm sewers along the streets as part of the combined sewer separation program. The foundation drains contribute significant stormwater, and are often the cause of basement flooding. As City building codes have changed over the years, foundation drains for newly construction/renovated homes must no longer be connected to the sanitary sewer system.

• Storm sewer: The storm sewer collects stormwater from catchbasins (street drains), eavestroughs, weeping tiles (in many areas of the city) and carries these flows into nearby streams or Lake Ontario.
• Combined sewer: In older parts of the city, stormwater and sewage are collected in the same pipe known as a combined sewer. Similar to the sanitary sewer, this type of sewer is connected to your home’s plumbing fixtures (toilets, sinks, laundry, etc.), but also conveys stormwater from weeping tiles and roof downspouts of buildings, as well as from catch basins, street drains, etc. (similar to storm sewers). During normal weather conditions, all the wastewater in the combined sewer is treated at the sewage treatment plant. However, in a heavy rainfall or spring thaw, the stormwater and the sewage mixture may overload the combined sewer system. Basement flooding may happen because the overloaded sewer forces wastewater back through the sewer pipes where it escapes through floor drains or any other low-lying plumbing fixtures in the basement.

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City acts to stop flooding

The City of Toronto has taken steps to stop the overloading of the sewers and basement flooding. Some of these initiatives have also improved storm water quality. Action taken to date includes:

• An engineering review in 2008 addressing basement flooding.
• Increased public education about the importance of isolating your home from the sewer system.
• Financial incentives (Basement Flooding Protection Subsidy Program) for property owners to help protect their property from flooding.
• Improvements to local sewer systems (sanitary and storm.)
• Stormwater detention ponds and constructed wetlands – these initiatives keep stormwater out of the sewers and use natural systems to remove pollutants, which leads to a higher quality of storm water ultimately being released into Lake Ontario.
• Water-efficiency programs to reduce wastewater volume.

Solutions to wet basements

One of the major factors contributing to the basement flooding is the lack of overland flow routes for storm drainage during extreme storms. In addition, the lack of proper controls on your property, such as downspout disconnection and proper lot grading are also contributing factors.

There are some simple steps you can take to reduce the likelihood of basement flooding.

• Check for and fix leaks in walls, floors, windows and foundations.
• Clear overflowing eavestroughs and downspouts of leaves and other debris that prevent proper drainage.
• Make sure your disconnected downspouts are draining properly, ideally 1.8 meters (six feet) from your basement walls.
• Install flood-proofing devices, such as back-water valves, sump pumps, floor drains or caps, and check these items routinely to ensure they’re working properly. The City offers subsidies for the installation of these items through the Basement Flooding Protection Subsidy Program.
• Plant trees and other native species.
• Consider soft-surface landscaping that allows storm water to soak into the ground rather than run directly into the local sewer systems (i.e. increased sodded areas, porous pavement).
• Check with your insurance provider to make sure you are covered.

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Action list for a basement flood

Call 311 immediately, 24 hours a day, seven days a week. City staff will inspect the problem, assess the flooding and attempt to determine the source(s). If the problem is a City responsibility, we will immediately fix it. If the problem is the homeowner’s responsibility, we will advise you of a possible course of action you should take.

Call your insurance provider as soon as possible and report property damage caused by the flooding:

• Take photos of damage caused by flooding for your insurance claim.
• Keep receipts from emergency repair work or clean-ups done to prevent or reduce further damage.
• If the flooding is a result of a blocked drain pipe, leaking foundation walls or poor lot drainage on your property, the property owner is responsible for repairs and any subsequent damage caused by flooding for your insurance claim. Make sure your disconnected downspouts are draining properly, ideally 1.8 meters (six feet) from your basement walls. Learn how to Disconnect your Downspout with our "Do it yourself" instructions.
• The City of Toronto will make all repairs to City pipes.
• Frequently, sewers or drains are blocked by tree roots – the City will help clear the blockage if the tree is on City property and a grant is available for repairs on private property. Call 311.
• You may submit a claim in writing with your name, telephone number, home address, date, location and details of incident and send it to:

City Clerk’s Office
City of Toronto
City Hall, 100 Queen Street West
Toronto, M5H 2N2

Fax: 416-392-1867
Email clerk@toronto.ca.

Your claim will be forwarded to the City’s insurance adjustors for evaluation. A letter of acknowledgement will be sent to you.

Be mindful of health and safety when cleaning up your flooded basement. Exposure to contaminants carried by flood water or sewer back-ups into basements can be dangerous. Homeowners may be exposed to waterborne diseases, including diarrhea illnesses, corrosive cleaning agents and irritants found in leftover sludge from a flooded basement. Electrical accidents may occur because of contact with water and electricity.

• Dress appropriately - wear overalls, gloves, protective eyeglasses, rubber boots and a mask.
• Open windows to let fresh air in.
• Stay away from electrical equipment and do not attempt to change any fuses if standing in water or on damp ground.
• If you can, shut-off the electrical power.
• Minor debris can be put out for regular garbage pick-up (See your Garbage and Recycling Collection Calendar for information).
• Scrub furniture affected by flood water with soap and clean water and place it outside in sunny area to dry (weather permitting) or steam clean.
• Clean and deodorize carpets, or have them professionally cleaned.
• Disinfect walls and floors using a chlorine bleach and water solution (one part bleach to 10 parts water) - make sure the area is thoroughly aired-out and dry before reoccupying it.
• Wash clothing following manufacturer's instructions.
• Throw out canned foods, home-prepared food in jars, meats and dairy products and any packaged foods that may have been affected by the flood waters - check for damaged packaging, leaks, and corrosion at seams and joints of cans.
• If your freezer's power is off, move the frozen food to another freezer or throw it out if you can't keep it frozen.
• Consider getting help with flooding clean-up - look in the Yellow Pages under "Water Damage Restoration".

For information, call 311.

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