If you have a finished basement, a suite, or a bathroom below street level, this is the highest-value item on the autumn list.
What actually happens
During heavy rain the municipal sewer can fill faster than it drains. When it surcharges, the water in the main has to go somewhere, and it finds the lowest opening connected to it. If that is your basement floor drain, shower or laundry standpipe, it comes up there.
A backwater valve is a one-way gate installed on your building drain. Under normal flow it stays open. When flow reverses, a flap closes and holds it back.
Who needs one
- Any home with a finished basement
- Any home with a basement suite, which in Port Coquitlam and parts of Surrey is a large share of the housing stock
- Any fixture below street level — a floor drain, a basement bathroom, a laundry
- Older neighbourhoods on combined sewers, which Vancouver is still progressively separating
If your basement has flooded before and nobody could find a blockage, a surcharging main is the first thing to rule out.
Rebates and insurance
Several Lower Mainland municipalities have offered rebates toward retrofitting a backwater valve, and some insurers treat sewer backup coverage differently once one is fitted. Both change from year to year, so confirm the current position with your city and your broker before you book — it is worth the two phone calls.
What it costs you to wait
A sewer backup is not a water leak. It is contaminated water through finished space, and the remediation is correspondingly worse. The average basement flood runs about $43,000, and a backup claim typically sits at the higher end of that.
Booking it
We work across Langley, Surrey, Vancouver, Burnaby, Richmond, the North Shore, the Tri-Cities and the Fraser Valley. Licensed and insured, with a written workmanship warranty set out in our Service Guarantee.
This is one of eight jobs we cover in the autumn plumbing guide for the Lower Mainland.
Related guides
- Perimeter Drainage: Why Basements Get Damp in November, Not August
- Outdoor Taps and the Lower Mainland Freeze Nobody Plans For
- Boiler and Hydronic Heating Service: Book It Before the Heating Season
- Leak Detection and Automatic Shut-Off: For the House That Sits Empty at Christmas
