Basement Flooding in Lévis: Ice Jams on the Chaudière, Old Sewers in the Old Sectors, and the Fixes That Work

Ice jams, sewers and the melt

River flooding on the Chaudière is an ice-jam event: the City and the province watch the river in March and April, the jam forms, and the water behind it rises fast into the low streets of Charny and Saint-Nicolas, sometimes with ice pushed into yards. Sewer backup arrives at the floor drain, a basement toilet or the laundry standpipe during or just after heavy rain and smells like sewage; the old sectors on the oldest sewers are most exposed. Groundwater arrives clear at the wall-floor joint and through cracks in the melt, and the post-1970 bungalows across the plateau depend on a sump pump and a French drain that has not silted.

Photograph where the water first appeared and when. An ice-jam warning, a storm and a smell, or a melt and clear water each point to a different fix.

What the fixes do, and what Quebec requires

A backwater valve is a one-way flap on the drain that closes when the sewer surcharges so sewage cannot flow back into the house; Quebec’s plumbing code has required them on the below-grade fixtures of most homes for years, and many older Lévis houses have none or have one seized open. A sump pump with a pit collects groundwater from the French drain and pumps it outside; a battery backup keeps it running through the outages that come with the storms. Quebec insurers have held that a missing or unmaintained backwater valve can reduce a claim.

The City of Lévis requires a permit for the work and has offered protective plumbing programs at times; check the City’s current page before signing a quote. Gutters connected to the sanitary sewer must be disconnected under the City’s by-laws.

• City of Lévis permit and any current program checked
• RBQ-licensed plumbing contractor
• Camera inspection recording and locate
• Backwater valves present and tested on every below-grade fixture
• Sump pump tested in March, backup and alarm

Who owns which pipe, and the flood plain

The City of Lévis owns the sanitary and storm sewers beyond your property line and the water supply; the lateral on your property is yours, subject to the City’s by-laws. A camera inspection with a locate tells you which side a break or blockage is on. Keep the recording; an insurer will want it, and sewer backup and overland water are separate endorsements on a Quebec home policy. The provincial flood-plain maps along the Chaudière restrict rebuilding and major renovation in the zones near the river, and insurers use them; ask your broker what is available at your address.

Old sectors and the French drain

The old sectors of Lévis and Lauzon along the cliff have stone and brick foundations and clay or no French drains; a waterproofer digs the exterior, applies a membrane and a new French drain with a cleanout, and connects it to a sump or the storm sewer where the City allows. Where the lot does not allow excavation, interior drainage to a sump and repointed mortar are the alternative. Extend the gutters well away from the foundation and correct grading before spending on anything underground. Excavation and drainage work must be done by an RBQ-licensed contractor.