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Water and Wastewater


Beware of High-Pressure Door-to-Door Sales Agents.

Residents are reminded that the Region of Peel and the City of Mississauga do not employ or authorize other companies to install backwater valves or sump pumps on their behalf.

Basement Flooding

In the unfortunate case that you experience basement flooding, call your insurance company right away. They can help assess the damage and give you advice on how to minimize ongoing damage.

Interested in learning more about downspout disconnection and managing stormwater effectively on your property? Register for upcoming “Greening Your Grounds – Getting Started” workshops from the Toronto and Region Conservation Authority (TRCA) here.

Types of Basement Flooding

Overland flooding

Overland flooding is water that flows over land and is usually generated by rainfall or snowmelt. Your home’s proximity to any water features, channel restrictions and the slope of the terrain contribute to overland flow. Water from overland flooding can enter through your home’s doors, windows, reverse sloping driveways and/or holes in the walls of the foundation.

This type of basement flooding is generally not covered by insurance and is a homeowners’ responsibility to fix the deficiencies, as it pertains to general maintenance of your home.

When landscaping or gardening, soil may to settle in a way that slopes toward the house. If not corrected, it can lead to rainwater or snow melt flowing toward the house. This is also considered overland flow.

Overland flow is often managed by the local municipality’s storm sewer system. You are responsible for the proper grading of your lot to direct overland flow away from your home and to the storm sewer system where appropriate.

Understanding storms

Storms are classified in different ways. There are storms that are classified as 10 year storms, 20 year storms, 50 year storms and 100 year storms. These are all mixed in with the regularly occurring rain showers that we normally experience. Being called a 10 year storm doesn’t necessarily mean it happens once in 10 years. It relates to the probability of having a storm of that size in one year.

A 100 year storm is an event that statistically has a one per cent chance of occurring in any given year. More accurately, it should be called a "1-in-100 chance storm.”

During storms of this size, you will see rainwater reaching levels and flowing in ways not normally seen in regular rainfalls.

Seepage or pressure leaks

Water can leak into your basement through holes and cracks in foundation walls, floors and from your rooftop. Particularly in older homes (15 years or older), cracks may have developed in the foundation or floor slab, which allows water to enter the basement.

This type of basement flooding is generally not covered by insurance and is a homeowners’ responsibility to fix the deficiencies, as it pertains to general maintenance of your home.

Sewer surcharge

Basement surcharge or basement flooding, where the water enters your home through the sanitary sewer floor drains, sinks or toilets are mainly caused by blockages or pipe capacity.

  1. A blockage in the homeowners pipe
  2. A common cause of sewer surcharge is a blockage in the pipe that runs between your home and the Region's main sanitary sewer pipe. Blockages in sewers can be caused by soil settlement, misaligned joints, root infiltration or pipe collapses. Sewer blockages can also be caused by items such as cooking grease, rags, or pieces of solid debris that have been flushed down a household drain or toilet.

    The sewer pipe that runs from your home to the property line is owned and maintained by the homeowner.

    If you suspect a problem with your sanitary sewer pipe, call the Region of Peel at 905-791-7800. Our 24 hour sewer back up service helps diagnose sewer problems.

  3. A blockage in the Region’s pipe
  4. Sewer surcharges may also be caused when there is a blockage in the Region's main sanitary sewer pipe. The Region of Peel maintains the sanitary system by regularly flushing water through it and running a TV camera in to check the condition of the pipe. The Region also schedules and performs maintenance when appropriate.

  5. Too much water in the sanitary sewer (inflow and infiltration)
  6. Inflow
    Sources of water flowing into the sanitary sewer system, other than wastewater, are called inflow sources. Inflow enters a sanitary sewer from sources such as roof drains, land drains and manhole covers.

    Overland flow may also cause a sanitary sewer surcharge. In the event of a storm where there is a significant amount of storm water pooling on the streets or significant runoff from roof structures, storm water can enter the sanitary sewer system in several ways:

    • If the storm water runoff is pooling the streets, it might enter the sanitary sewer system through manhole cover holes or cracks.
    • Downspouts may be directly connected with the sanitary sewer system. In this case, all storm runoff from the roof area drains directly into the sanitary sewer. This reduces the sanitary pipe capacity and when the capacity is completely used, the system backs up, potentially flooding basements.
    • Drainage area of weeping tiles may be directly connected with the sanitary drainage system. In this case, all storm runoff from the drainage area of weeping tiles drains directly into the sanitary sewer. This reduces the sanitary pipe capacity and when the capacity is completely used, the system backs up, potentially flooding basements.

Downspouts and weeping tiles should be diverting water back onto the property or to the larger storm sewer and not the sanitary sewer.

Sources of indirect flow of water into the sanitary sewer system are called infiltration sources. Infiltration is water that enters a sanitary sewer from cracks, joints, broken pipe and defects in the sanitary pipes or defective connections between pipes. Infiltration is usually based on the height of the groundwater table at a given time.

The sanitary pipe on your private property may allow excessive infiltration of water due to poor maintenance or collapse. If you suspect this is the case, call the Region of Peel immediately.

What can you do to protect your property?

There are steps which should be taken everyday to protect your home and the sanitary system.

  • Ensure that lot grading directs water away from your foundation
  • Repair any cracks or holes in the basement walls or floors
  • Disconnect down spouts to direct water onto your lawn and away from your home
  • Consider using a rain barrel to collect rainwater
  • Keep your sewer pipe in good working order, free from collapse, tree roots, free of debris and fats, oils or greases that can lead to blockages
  • Be aware of what items are flushed or put down the sink. Seemingly small items can cause blockages when they accumulate

Protection of your building and contents should always involve insurance coverage which can reimburse the costs you incur when sewer water damages your building or contents, subject to limitations and conditions in your insurance policy. However home insurance policies do not automatically contain “Sewer Back up” coverage also known as “Broad Water” coverage and it is this coverage that will protect you. Don’t wait until after a sewer backs up or your property sustains damage to find out if you have coverage: speak with your Insurance representative today to ensure that your property is completely covered.

Visit the city of Mississauga’s website on drainage and flooding (external PDF)

Flood prevention devices

Backwater valves (also known as check valves and backflow prevention devices)

A backwater valve is placed at the exit point of the sanitary pipe under your home. Under normal conditions, the valve allows wastewater to flow from your property out to the main sanitary sewer at the street. In conditions when wastewater flows back toward your home, the valve closes and prevents it from re-entering.

This may seem like the perfect solution to a backflow event; however, there are limitations to the effectiveness and ease of use of the device.

Once the backwater valve is closed (or in check), wastewater cannot escape to the sewer system.

This means that you cannot bathe, shower, wash clothes, run the dishwasher, flush the toilet or put anything in the system until the conditions that have caused the backflow have been eliminated and the valve returns to its normal position.

Placement of the device is also critical. It must be placed outside of the last exit point of the sanitary sewer pipe from your home.

Backwater valves also need maintenance; they can be affected by grease build-up and debris that can cause them to not close when it needs to. Watch this video from the Institute for Catastrophic Loss Reduction outlining proper maintenance.

Sump pumps and weeping tiles

Around your home’s foundation is a perforated pipe called a weeping tile or foundation drain. The foundation drain collects and drains excess groundwater away from the foundation. Downspouts may also be connected to the weeping tile.

If your home frequently has an excess of groundwater, a sump pump can assist the foundation drain by moving the water up and away from the foundation.

A sump pump is a device that is placed into a sump pit (that collects water from your home’s foundation drain) and pumps it out of the pit onto your lawn, away from your home.

There are limitations to the effectiveness and ease of use of the device.

  • Sump pumps are designed to pump water at a slow rate and may not pump water fast enough if your basement is flooding
  • Sump pumps need maintenance
  • Sump pumps run on electricity and will not work during a power outage

Have a professional assess whether you need a sump pump and assist with selection and installation.

What to do if your basement floods

In the unfortunate event that your basement floods, immediately contact your insurance company or representative. Provided you have coverage, your Insurance Company can recommend the services of a qualified contractor experienced in mitigating and restoring the damage sustained

If you do not have insurance, consider safety and consider contacting an experienced restoration contractor to ensure the damage is mitigated and properly restored.

To report flooding on roads and in your neighbourhood please call 3-1-1. In Caledon call 905-584-2272, ext.4238. If you have water inside your home, please call the Region of Peel at 905-791-7800.

Claims for Damages

If you or your insurance company are of the opinion that The Region or local municipality ought to provide compensation for the damages, a written request for the same should be directed to the Risk Management or Clerks department at The Region or local municipality.

Unlike a claim under one’s home insurance policy, a claim against a municipality is usually founded upon an allegation of negligence. In order for a Municipality to compensate homeowners for damage resulting from the escape of water from a sanitary or storm sewer system, the Municipality must have done or failed to have done something that caused the back-up. The mere occurrence of a blockage or surcharge does not mean a Municipality is or will be found responsible to pay for the resulting damage: despite all prudent measures, blockages and back-ups will occur within a system that is so extensive.

Risk Management will consider the factors that caused the back-up including the design, operation and maintenance of the system. The investigation of these factors can take some time, dependant upon the scale of the back-up. Once the investigation is complete, Risk Management will communicate a decision to the homeowner or their insurer.

During this process, it is the responsibility of the homeowner to take all reasonable steps to mitigate their damage.

Clean up

If your basement has flooded, it’s important to take the proper care and maintenance when cleaning.

  1. Be aware of electrical hazards when you enter the affected area. Water conducts electricity.

  2. Be aware of health hazards when you enter the affected area. Water can carry bacteria that may affect health. Proper safety clothing should be used.

  3. It is important that:

    • The water is extracted/drained,
    • Building finishes and contents that have either been submerged or have absorbed water be inspected/removed and assessed for restoration or disposal. (It is advisable that an accredited restoration contractor be consulted)
    • Drying of the exposed structure takes place.

Mould can begin to grow within 48 hours of water exposure may cause adverse health conditions. Properly drying areas and objects that have water damage will help reduce further mould growth and damage to the premises.

  1. Photos of the affected area should be obtained and preserved, prior to the removal of the items/finishes.

More information on flooding:

Revised: Wednesday November 09 2016


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