Backwater valves
A backwater valve is a one-way flap on the sanitary line that stops the municipal sewer backing up into your basement during a storm. It applies to houses on Peel sewers; a house on a septic system has no sewer to back up.
- Peel rebate60% up to $1,500
- NeedsTown of Caledon permit + inspection
- Seasonall year
Who needs one
Houses connected to the Region of Peel sanitary sewer: Bolton, Caledon East, Mayfield West and the other serviced areas of the Town. During a heavy storm the sewer can fill faster than it drains, and the water looks for the lowest opening, which is a basement floor drain, shower or toilet. A backwater valve closes when flow reverses and keeps it out.
If your house is on a septic system, which is the case for most of rural Caledon and many of the villages, there is no sewer to back up and a backwater valve has nothing to do. The assessment tells you which you have.
How it is installed
- The lateral is located where it leaves the house, usually under the basement floor near the front wall.
- A Town of Caledon building permit is obtained before the work. The Region’s rebate requires it.
- The floor is opened over the pipe, a section is cut out, and the valve is installed in line with its access cover at floor level.
- The Town inspects the installation before the floor is closed.
- The floor is re-poured. The valve’s clear cover stays accessible so the flap can be checked and cleaned.
The Region of Peel rebate
The Region reimburses 60% of the invoiced amount, up to $1,500 including tax, for a sanitary backwater valve installed after July 16, 2024 in a single, semi-detached or townhouse residence in Brampton, Mississauga or the Town of Caledon. The main conditions, as published by the Region:
- The applicant is an individual homeowner, not a business, and the valve serves one dwelling.
- A building permit from the Town of Caledon is obtained before installation, and a municipal inspector approves the work afterward.
- The installer is a licensed, qualified contractor.
- One rebate per residence every 10 years.
- Downspouts disconnected from the sewer are strongly recommended; if they are not, the Region asks for a signed acknowledgement.
Applications are reviewed within five business days and approved cheques are mailed in four to six weeks. The form and the current terms are on the Region of Peel’s rebate page; check it before you budget, since the Region sets and changes the amounts.
What we provide for the application: the permit, the inspection sign-off and an itemized invoice that shows the valve and its installation separately from any other work done the same day.
Questions about backwater valves
Does a backwater valve stop groundwater?
No. It only stops sewage from the municipal sewer flowing backward into the house. Groundwater through walls, cracks and the floor is a waterproofing problem and needs a drain, a membrane or an injection.
Does the valve need maintenance?
Yes. The flap should be checked once or twice a year through the access cover and cleaned if debris has collected. A flap that is stuck open protects nothing.
Can I still use water while it is closed?
No. While the valve is closed during a backup, nothing in the house can drain. It opens again on its own once the sewer level drops.
Is the rebate available for a house on septic?
No. The program is for houses connected to the Region’s sanitary sewer. A septic system does not back up from the street; its own problems are handled by a septic contractor.
Next step
Permit, valve, inspection, invoice
One visit confirms whether the house is on sewer or septic and whether a valve is worth installing.
Book a free assessment