From LF Builders, the renovation company behind this forum. Figures checked against City of Toronto, Ontario Building Code and Insurance Bureau of Canada pages on October 30, 2026. If something here has changed, reply and we’ll correct it.
Short answer: Cut the power and stay out of the water, report the flooding to 311, and call your insurer the same day, with photos and receipts kept. Sewer backup coverage is an optional add-on to most home policies, so check yours. For prevention work completed on or after November 12, 2025, the City of Toronto pays 80% of the cost of a backwater valve, sump pump, battery backup, foundation-drain disconnection and a plumbing assessment, up to $6,650 per property. The contractor needs a City licence, and a backwater valve needs a permit and inspection.
In the first 24 hours
These steps come from the City’s own basement flooding page:
- Power first. Call Toronto Hydro to have the power shut off, and stay away from electrical equipment. Have a licensed electrical contractor check the area before you go back in.
- If it’s a sewer backup, avoid using toilets and sinks until it’s resolved.
- Report it to the City through 311 (phone or 311 online). City staff investigate.
- Call your insurer as soon as possible. Take photos, and keep every receipt from emergency repair or clean-up.
- Clean up safely. Keep children and pets out, and wear gloves, boots, eye protection and a mask. Wash with hot water and detergent, sanitize with a bleach solution, and throw out what can’t be cleaned, including any food that touched flood water. For sewage, the City suggests considering a professional clean-up company with that experience.
- If you smell gas, leave the house and call the gas company.
Already flooded and not sure what to do next? Ask in My basement flooded in the Toronto storm, what do I do first?
What insurance covers
Sewer backup and overland flood are optional coverages in Canada, not part of a standard home policy. Insurers often sell them together, and availability depends on your area’s risk (Insurance Bureau of Canada). Read your policy for the words “sewer backup” and “overland water” before the next storm, not after.
What the City pays (2026)
The Basement Flooding Protection Subsidy pays 80% of the invoiced cost, up to these limits, for work completed on or after November 12, 2025:
| Item | Maximum |
|---|---|
| Backwater valve (up to two) | $1,600 each |
| Sump pump | $2,250 |
| Sump pump battery backup | $300 |
| Foundation drain severance and capping | $400 |
| Home plumbing assessment | $500 |
| Total per property | $6,650 |
The expanded program took effect May 1, 2026, but it covers work completed back to November 12, 2025. The old limits were $1,250 for a valve, $1,750 for a sump pump and $400 for severance, $3,400 in total. Reaching $6,650 takes two valves plus every other item.
To qualify:
- You’re the registered owner of a single-family home, duplex, triplex or fourplex.
- Your contractor holds a valid City of Toronto business licence: Plumbing (T94), Plumbing & Heating (T92) or Drain (T87). Check the licence before work starts.
- The backwater valve has a building permit and passes inspection before it’s covered up.
- Your downspouts are disconnected, or you have an exemption.
- You have no overdue taxes or debts with the City.
- You apply within 2 years of installation.
Backwater valves: when the code requires one
The 2024 Ontario Building Code (Article 7.4.6.4) requires a backwater valve where a building drain or branch may be subject to backflow. That doesn’t mean every house. In Toronto, installing one takes a standalone drain permit. No drawings are needed for a one- or two-unit house, and the fee is $38.67 (from January 1, 2026). The inspection has to happen before the valve is covered.
Code questions about full-port valves are discussed in this thread, and real costs and sizing in GTA backwater valve installation 2026.
Downspouts
Connecting downspouts to the sewer is banned under Toronto Municipal Code Chapter 681. An exemption exists where disconnecting would be hazardous or isn’t technically feasible. After disconnecting, the water can’t run onto a neighbour’s property, a sidewalk or a driveway. The City suggests draining it about 2 m from the foundation, and in winter, don’t run extensions across walkways. Eligible low-income seniors and people with disabilities can get up to $500 toward the work. See Toronto downspout disconnection 2026.
Sump pump and battery backup
A sump pump only helps while it runs, and storms knock out power. The battery backup is its own $300 line in the subsidy. See GTA sump pump battery backup.
Interior vs. exterior waterproofing
Interior systems manage water that’s already in; exterior membranes stop it at the wall. Which one fits depends on where the water comes from. The full comparison, and what a good quote should spell out, is in Basement waterproofing in Ontario: interior vs. exterior.
Help us make this better
Real experiences make this page more useful than any guide. If you went through it this year, tell us:
- How long did the City take to pay your subsidy, and was any item refused?
- What did your plumber charge for a backwater valve, with the permit and inspection included?
- Did your sewer backup coverage pay out, and what did the adjuster ask for?
Sources
- City of Toronto, Basement Flooding (modified June 30, 2026)
- City of Toronto, Basement Flooding Protection Subsidy Program (modified June 18, 2026)
- City of Toronto, Backwater valve permit guide (modified July 14, 2026)
- City of Toronto, Mandatory downspout disconnection and Municipal Code Ch. 681
- Government of Ontario, 2024 Building Code Compendium, Part 7
- Insurance Bureau of Canada, Flood and water
