Basement Flooding in Thunder Bay: What the 2012 Flood Taught the City and What to Do Now

Work out which kind of flooding you have

Sewer backup arrives from below, at the floor drain, a basement toilet or the laundry standpipe, during or just after heavy rain, and it smells like sewage; the older neighbourhoods on combined sewers and the low ground near the lake and the rivers are most exposed. Groundwater arrives at the wall-floor joint, through cracks and window wells, in the spring melt and after long rains; Thunder Bay’s clay soils hold water against foundations. Surface water comes over window wells and under doors where grading slopes toward the house.

Photograph where the water first appeared and when. That answer decides whether you need a plumber for a backwater valve, a waterproofer for drainage, a landscaper for grading, or a call to the City about the connection.

What the fixes do, and what the City has offered

A backwater valve is a one-way flap on the sanitary lateral that closes when the sewer surcharges so sewage cannot flow back into the house; while it is closed nothing in the house drains, which is why plumbers say not to run water during a storm. A sump pump with a pit collects groundwater from the foundation drain and pumps it outside; a battery backup keeps it running through the outages that arrive with the storms. Disconnecting the foundation drain from the sanitary sewer, where it is connected, takes groundwater out of the overloaded system.

After 2012 the City of Thunder Bay offered a subsidy program for backwater valves, sump pumps and related protective plumbing at eligible homes, with conditions that the work be done by a licensed plumber under a City permit. The programs change; read the City’s current page before signing a quote, and ask the plumber to quote the valve and the pump separately.

• City’s current subsidy program checked for eligibility
• Licensed plumber and City plumbing permit number
• Camera inspection recording and locate
• Sump pump tested and battery backup quoted
• Grading and downspouts checked around the foundation

Who owns which pipe

In Thunder Bay the owner is responsible for the sewer lateral on private property up to the property line, and the City for the section from the property line to the main. A camera inspection with a locate tells you which side a break or blockage is on; if it is the City’s side, contact the City, and if it is yours, the repair is yours. Keep the recording, because an insurer will want it for a sewer backup claim.

Sewer backup and overland water are usually separate add-ons on an Ontario home policy, and after 2012 some Thunder Bay insurers changed their terms. Check both coverages before the next storm, and ask whether a backwater valve changes the premium.

Spring melt and the north

Thunder Bay’s spring melt arrives fast after a long winter, and a sump pump that has not run since October is the most common failure. Lift the float in March, listen for the pump, and check that the discharge line outside is not frozen or buried in snow. Extend downspouts well away from the foundation and correct grading before spending on anything underground. Older houses in the north and south cores often have clay weeping tile that has silted up, which a camera inspection will show.