If you've never heard of a backwater valve, you're in the majority. It's one of the least glamorous and most important devices a house can have — and both the City of Mississauga and the Region of Peel will pay you to install one.
The problem it solves
Your home's drains connect to the municipal sewer under your street. During an intense storm, that sewer can fill beyond capacity. When it does, the sewage has to go somewhere — and it flows backwards up the pipes, into the lowest drains it can find. That's your basement floor drain, your basement toilet, your laundry standpipe.
This is a sewer backup, and it's the nastiest kind of basement flood: it isn't rainwater, it's sewage. Insurance claims routinely run into tens of thousands of dollars, and many insurers now cap or refuse sewer-backup coverage in flood-prone neighbourhoods.
How the valve works
A backwater valve is a simple one-way gate installed in the sewer pipe where it leaves your home. Water flowing out (the normal direction) pushes the gate open. Water trying to flow in pushes it shut. No electricity, no moving parts to speak of, nothing for you to operate — it just sits in the line and does its job when the storm hits.
Why your home probably has two sewer pipes (and can get two rebates)
Most Mississauga homes have two separate laterals: a sanitary line that carries sewage, and a storm line that carries rain and groundwater. Each can back up. Each can get its own valve. And each valve has its own rebate, from a different government:
- Sanitary backwater valve — Region of Peel rebates 60% of your invoice, up to $1,500.
- Storm lateral backwater valve — City of Mississauga rebates up to $1,500 under the Basement Flooding Prevention program.
Because they're different pipes and different programs, both rebates can be claimed on the same home.
What installation actually involves
The valve is installed by opening a small section of the basement floor near where the sewer line exits the house, cutting the valve into the line, and restoring the concrete. A permit is required before the work (the rebate programs insist on it), and a municipal inspector verifies the installation afterwards. Done by a licensed plumber, it's typically a one-day job.
What it costs after rebates
This is the part that surprises people: between the Peel rebate (60% of the sanitary valve) and the City rebate (up to $1,500 on the storm valve), the out-of-pocket cost of protecting both lines is a fraction of the sticker price. Run your address through our 2-minute estimate tool and you'll see the exact numbers for your home — price, rebates, and net cost, itemized.