YTZ Basement Waterproofing Toronto

Backwater Valve Installation Toronto

A backwater valve lets sewage flow out but closes automatically when the city main backs up, protecting your basement.

Open 24/7 · Open 24 hours, 7 days a week

What is backwater valve installation?

A backwater valve is a one-way gate installed on your home's main sewer line. Under normal conditions it stays open so household sewage flows out to the city main. If the city sewer backs up — which happens in heavy Toronto storms — the rising water pushes the valve closed so sewage cannot flow back into your basement through your floor drain.

It is one of the most effective ways to protect a Toronto basement from sewer backup, and it is a key item covered by the City of Toronto Basement Flooding Protection Subsidy (up to $1,600 per device, maximum two). We install main-line backwater valves in the basement floor and make sure the rest of your plumbing is compatible.

Finished gravel drainage strip beside a foundation wall and basement window

Signs you need backwater valve

Sewer smell or backup in storms

Water coming up through the floor drain during heavy rain is the clearest sign of city sewer backup.

Older home, no valve

Most Toronto homes built before the 2000s have no backwater protection on the main line.

You live in a flood-prone area

Some Toronto neighborhoods are on the city's basement flooding priority list.

You want the rebate

A backwater valve is eligible for the Toronto subsidy — see our rebate page for the rules.

Our process

Step 1
Locate main line

We find where the main sewer exits the basement and confirm the right install point.
Step 2
Cut floor & pipe

We remove a section of concrete floor and cut into the main line to fit the valve.
Step 3
Install valve

We set the backwater valve, reconnect the line, and confirm it moves freely.
Step 4
Restore floor

We pour new concrete over the access box and clean up.

What does it cost?

A backwater valve installation in Toronto typically runs about $2,000–$4,500 depending on floor depth and the existing plumbing. Exact price after a free inspection.

Get my free quote

Backwater Valve FAQ

Is a backwater valve eligible for the Toronto subsidy?

A backwater valve is one of the items covered by the City of Toronto Basement Flooding Protection Subsidy. Program rules are set by the City and can change — see our rebate page for details.

Do I need to break the basement floor?

Most main-line backwater valves are installed in the floor drain area, which requires cutting and removing a section of concrete floor, then restoring it.

Will it stop all basement flooding?

A backwater valve stops sewer backup through the main line. It does not stop water coming through foundation walls or windows, which is a separate problem.

Wet basement? Book a free inspection

Call (647) 556-2391 Book a Free Inspection