Basement Flooding: Who Should You Call?
Urgency: EmergencyUpdated 2026-08-31
Short answer
Cut power to the basement at the panel before entering standing water, then call a restoration company to extract and dry, and a plumber to diagnose the cause. Document everything with photos and call your insurer the same day — Ontario policies typically require prompt notice for sewer backup and overland water claims.
Who to call: A water-damage restoration company for extraction, and a licensed plumber for the drain, sump or backwater valve.
What to do right now
- 1Shut off electricity to the basement before stepping into any standing water.
- 2Do not use the toilets, sinks or washing machine if the backup came from the drain.
- 3Photograph and video everything before you move or discard anything.
- 4Call your insurance broker the same day and ask what your policy covers for sewer backup.
Most likely causes
- Sewer or storm backup
- Heavy summer storms overwhelm municipal lines and push water back through the floor drain.
- Sump pump failure
- A pump that has burned out, jammed, or lost power during the storm that needed it most.
- Foundation cracks and window wells
- Surface water entering through poor grading, blocked window wells, or hairline foundation cracks.
- Burst pipe or failed water heater
- Clean-water flooding that has nothing to do with the weather.
What it typically costs in the GTA
$1,500–$5,000 for professional extraction and drying of a finished basement. $400–$900 for a sump pump replacement, more with a battery backup. $2,000–$4,000 for a backwater valve — often partly rebated by GTA municipalities.
Ranges are typical market pricing for the Greater Toronto Area and vary with access, age of the home, and time of year. Always get the scope in writing before work starts.
First hour matters most
Water damage escalates on a clock. Drywall wicks water upward, insulation holds it, and mould begins within roughly 48 hours. Getting extraction started the same day is the difference between drying a basement and gutting it.
Preventing the next one
Most GTA municipalities — Toronto, Mississauga, Brampton and others — run subsidy programs for backwater valves, sump pumps and downspout disconnection. Combined with proper grading and clean eavestroughs, these address the great majority of repeat flooding.
- Install or service a backwater valve.
- Add a battery or water-powered backup to the sump pump.
- Extend downspouts at least two metres from the foundation.
- Regrade soil so it slopes away from the house.
Get the right pro on it
Describe the problem in your own words. We’ll work out which trade you need and connect you with suitable local pros. Free, no obligation.
Frequently asked questions
- Does home insurance cover basement flooding in Ontario?
- Sewer backup and overland water are usually optional endorsements rather than standard coverage. Check your policy before you need it.
- Can I dry the basement myself?
- For a small amount of clean water on a concrete floor, sometimes. For sewage, or anything that has soaked drywall, insulation or carpet, use a restoration company with proper drying equipment.
- How fast does mould grow after a flood?
- Typically within 24 to 48 hours on damp organic material such as drywall paper.