Telltale signs: backwater valve installation
During a heavy summer storm, the municipal sewer can fill faster than it empties. When that happens, water looks for the lowest opening it can find, which in most houses means the round grate in the basement slab. The valve is, in effect, a non-return flap fitted into the main drain: wastewater flows out normally, but a flap closes if flow reverses.
The device is worth considering if any of the following apply:
- Your basement has flooded through the floor drain before
- Neighbours on the street have experienced sewer backup
- A finished rec room or new washroom is planned for the lower level
- Your home sits low relative to the road
What we bring
- Submersible pump, check valve and union
- Pit liner, discharge pipe and ABS fittings
- Bucket and hose for the fill test
Tested before we leave
- Pit filled until the float trips the pump
- Check valve confirmed shut on the reverse
- Discharge traced to the outside outlet
On the job: what we open, clear and test
A proper mainline valve goes into the main drain inside the house, usually close to the front foundation wall. The work involves cutting the concrete floor, excavating around the pipe, setting the valve body at the correct slope, and installing an access cover so the valve can be inspected later. Concrete is then restored around the cover.
A permit from the City of Toronto is required, and the work must pass inspection. We camera the line first so that we are not setting a new valve onto a cracked or root-filled pipe.
What can change the job
- Floor finishes. Tile, carpet or a finished room over the drain adds removal and restoration time.
- Pipe depth and condition. Deep or deteriorated pipe makes excavation larger.
- Weeping tile connection. Some older homes have foundation drains tied into the sanitary line, which changes the design.
- Sump arrangements. Valves often pair with a sump pump installation where foundation water must be pumped out instead of drained.
Etobicoke homes and this job
Low-lying pockets near the Humber, Mimico Creek and Etobicoke Creek have seen backups during intense rainfall. Older homes in areas such as Princess Gardens often have finished basements worth protecting, while some lakeshore houses sit close to the water table. Mature trees can also complicate things, and our article on tree roots in sewer lines explains why we inspect before installing.
Toronto has for some years helped pay for qualifying flood devices through a city programme. Program details change, so we encourage you to read the current terms before work begins and keep your permit and invoice paperwork together.
Before you call
Gather any history you have: dates of past flooding, whether water came through the floor drain or through walls, and what the basement floor is finished with. Clear the area around the front wall where the main drain exits. If you already have a sump pump that sometimes fails, mention it, since sump pump repair may be part of the same visit.