Backwater valves around Edmonton: who needs one and the rebates available

A backwater valve lets sewage flow out of your house but closes when the city sewer backs up, so the water doesn't come up through your basement drains. If you're about to spend money finishing a basement, it's one of the cheapest ways to protect it.

Does your home have one?

Backwater valves weren't required in homes built before 1989, in Edmonton or Fort Saskatchewan. If your home is older and was never updated, it probably doesn't have one.

Rebates and subsidies

• Edmonton: EPCOR offers up to $800 toward an interior or exterior backwater valve for single-family homes and duplexes built before 1989 that have had sewer backup or are in a flood-prone area. A professional plumber must install it under a City permit. Funding is first come, first served.
• Sherwood Park and Strathcona County: the County refunds up to 50% of supply and installation, to a maximum of $1,200, for eligible single-family homes and duplexes built before 1989 on County sewer. Permits and inspection approval are needed before the rebate is paid.

Why do it during a basement project

Installing an interior valve usually means breaking the basement floor to reach the main drain. When the basement is still unfinished, or already being opened up for a bathroom, that work is much simpler than cutting into new flooring later.

Permits

Installing a backwater valve needs a plumbing permit, and EPCOR's subsidy requires a professional plumber and a City permit.

While the valve is closed

The flap closes automatically when sewage flows back from the main line. Until it reopens, wastewater from your own home has nowhere to go, so don't use the toilet, sink, shower, washer or dishwasher. Otherwise the water can rise through the floor drain into your basement.

Looking after it

Fort Saskatchewan recommends flushing, cleaning and exercising the valve at least once a year. EPCOR notes that debris around the gate is a common cause of malfunction, and suggests these steps:

• Wear safety glasses and rubber gloves, and have a flashlight ready.
• Remove the plug or panel, keeping the O-ring with the plug or cap.
• Check above and below the gate for debris, then clean the area and flush it with a bucket of water.
• Move the gate back and forth to confirm it moves freely. If it's stiff or rusty, oil it lightly.
• Replace the O-ring if it's cracked or damaged, then put the plug or panel back.

If cleaning doesn't solve the problem on an exterior valve, it may take a qualified contractor to fix.