Proper Collection of Storm Water and Sanitary Sewer Flows
Having a basic understanding of the plumbing and drainage system both inside and outside your home can help you to determine what steps you need to take to prevent basement flooding.
Your home has a separate storm water and wastewater (sanitary sewer) collection system. Halton Region is responsible for the wastewater collection system while your Local Municipality is responsible for storm water management. Any pipes or components of the plumbing system that are on the private property is the homeowner's responsibility and is referred to as private infrastructure.
The storm water system is designed to collect rain and snow melt (clear water) from streets and properties and direct this flow to a nearby pond, creek or lake. The sanitary sewer system is designed to collect water from toilets, sinks, showers and laundry facilities and direct it to wastewater treatment facilities where it receives a high level of treatment prior to being discharged back to the environment.
Until Building Code changes and subsequent by-laws were enacted in the mid to late 1970's, it was common practice to connect foundation drains and roof leaders directly to the sanitary sewer system. Although these connections are now no longer permitted as part of current construction practices, many areas in Halton Region constructed prior to 1978 continue to have direct storm water connections to the sanitary system which are now considered to be improper and are a major source of excessive inflow and infiltration (I & I). For more information on I&I please visit the web page.
Homes that have improper storm water connections in place can be more susceptible to basement flooding , due to the high volumes of storm water being directed to the sewer main in the street from sources such as downspouts and weeping tiles. Preventing basement flooding requires you to understand the source of the problem and to direct the storm drainage from your property appropriately.
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Possible Causes of Basement Flooding
There are several possible causes of basement flooding from sanitary sewer water, storm water , or a combination of both.
If your basement is flooded or wet from only storm water possible causes may be:
- Poor lot drainage resulting in water flowing toward the home rather than away from it.
- A leak in your home's foundation, basement walls, or basement windows and doors.
- Failure of the weeping tile system (foundation drains), resulting in water pressure building up around the foundation walls.
- Failure of a sump pump without battery backup used to pump water from the weeping tiles, which collect storm water from around the foundation of the home.
If your basement is flooded from a sewer backup, (or combined with storm water), possible causes may be:
- A blockage in the sanitary sewer lateral between your home and the sanitary sewer main in the street from paper, grease, tree roots or other material.
- A backup of wastewater in the sanitary sewer system through the floor drain or other fixtures in the basement, (possibly a combination of sanitary sewer water from the sanitary sewer system and storm water from the weeping tiles referred to as inflow and infiltration (I & I).
Most often basement flooding occurs after a heavy rainfall or snowmelt. Basement flooding from a sanitary sewer backup can occur when too much storm water enters the sanitary sewer system during wet weather events.
When this occurs, residences at lower elevations, especially those without adequate backflow protection, may experience a sewer backup into the basement from the floor drain or other plumbing fixtures. I & I is a significant contributor to basement flooding and is something that individual homeowners can effectively address by assessing your property drainage and making changes to remove improper storm water connections from the sanitary sewer system.
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How to Reduce the Risk of Basement Flooding
Storm Water
- Check for leaks in walls, floors, windows, or foundations and repair them.
- Improve your lot grading, making sure the ground slopes away from the exterior walls of your home.
- Ensure that borders around flower and shrub gardens do not create dams that retain water next to the house.
- Clean eaves troughs and downspouts of leaves and other debris. Make sure your downspouts are draining properly and directed at least two metres (six feet) from your basement walls.
Sewage / Storm Water
- Disconnect your downspouts if they are connected to the sanitary sewer system.
- Make sure your weeping tile drainage is not directed to the sanitary sewer system. Disconnect the weeping tile system of your home if improperly connected and install a sump pit with an automatic sump pump, with battery backup, that discharges to the surface to a suitable location approved by your Local Municipality.
- Install a backwater valve on the sanitary sewer lateral inside the basement to reduce the risk of sewage entering the basement. The weeping tiles must first be disconnected from the sanitary sewer system to avoid water collected from the weeping tiles from flooding the basement if the backwater valve is closed due to a sewer backup.
- Regularly inspect and maintain your home's flood-prevention devices such as backwater valves, sump pumps, floor drains, or caps to ensure they are working properly.
- Avoid pouring kitchen grease into your house drains as it will solidify in your plumbing system. Avoid putting objects into your plumbing system that were not meant to go down the toilet or drain.
Residents can also help by conserving water. In households without low-flow fixtures, up to 75% of water is used to flush toilets and take showers.
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What To Do If Your Basement Floods
If your basement floods and you suspect it is sanitary water call Halton Region at 905-825-6000 or toll-free at 1-866-442-5866 . Regional staff will inspect the problem, assess the flooding, attempt to determine the source and advise you of what actions you may take.
There is a flat rate charge for clearing a blockage that occurs on private property, should this be required. You should also call your insurance company as soon as possible and report any damage caused by the flooding. They will also advise you on how to proceed.
Be mindful of your health and safety when cleaning up your flooded basement. Floodwater may be unsanitary, contain irritants, corrosive cleaning agents and possibly sharp objects. Electrical accidents can occur if water is in contact with appliances. If concerned, stay out of the basement and contact a professional to assist in or conduct the cleanup and sanitization of your basement.
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Flood Prevention Assistance from Halton Region
Halton Region is now offering a one-time Basement Flood Prevention Subsidy, up to a maximum of $2,725.00, to assist:
- Halton residents who have a history of basement floods caused by a backup or surcharge of the sanitary sewer system.
- Halton residents who have not experienced flooding but would like to correct improper storm water connections and install a backwater valve.
Contact Information
For additional information on the Basement Flood Prevention Subsidy Program, or any other issues related to basement flooding, please contact the Program Coordinator Matt Stefanik at 905-825-6000 ext. 7918.
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