Basement Flooding & Sewer Backup

Water and electricity: stay out if water could reach outlets, cords, appliances or the panel.If the panel is in or near the water, call your electric utility before anyone enters the basement.

SOURCE

Where is the water coming from?

SOURCE A

A supply leak

Clean water from a burst pipe, fitting or appliance hose.

First: close the main shut-off.

SOURCE B

Groundwater

Water seeping in during rain or snowmelt — often a sump pump that failed or lost power.

First: check the sump pump has power and is running.

SOURCE C

Sewer backup

Dirty water rising through floor drains or toilets when city sewers are overloaded.

First: stop using all water in the home.

PROTECTION

The two devices that stop most basement floods

BACKWATER VALVE

Stops sewer water flowing back in

A one-way valve on the main sewer line that lets wastewater leave but closes when city sewers surcharge in a heavy storm. When it’s closed, don’t use fixtures — the water has nowhere to go.

Installation usually needs a plumbing permit, a licensed contractor and a municipal inspection.

Sump pit with a submersible pump, float switch and white discharge pipe

SUMP PUMP

Removes groundwater from the weeping tile

It pumps water collected around the foundation to the outside. Storms can knock out power, so a battery backup keeps it running when it’s needed most.

Discharge should drain onto a permeable surface away from the foundation.

SUBSIDIES

Your city may help pay for flood protection

Several Canadian municipalities run basement flooding protection programs that subsidise backwater valves, sump pumps and related work. Toronto’s program, for example, reimburses a percentage of eligible invoiced costs up to set limits per device.

Programs usually require permits, a licensed contractor and itemised invoices.
Eligibility, amounts and deadlines differ by city and change over time.
Check your municipality’s current program before work starts.

INSURANCE

Sewer backup often isn’t covered by default

Many basic home insurance policies exclude sewer backup unless a specific endorsement has been added. Some insurers look at whether protective devices are installed.

After the emergency

Basement floor drain with sewer water backing up around it — SEWAGESewer water is contaminated: gloves and boots, keep children and pets away, and plan on professional cleanup.

NEXT STEP

Water rising right now?

Request emergency service and tell us which source you think it is.

Request Emergency Service Open The Triage Guide