A backwater valve sits in the basement floor doing nothing for months. Then the sewer backs up and it has one job: close and seal. A greasy gate or a loose cap can stop that from happening, and that is what backwater valve maintenance is for. It takes a few minutes a few times a year. Here is how often to check the valve, what you can safely do yourself and when to call us. For the basics, including what a valve is and what installation costs, start with our backwater valve guide for Durham Region homeowners.
How often to check your backwater valve
The Government of Canada says to clean the valve at least twice a year to remove dirt and grease. It also highly recommends having a plumber inspect and maintain it. Depending on the valve type, that may mean at least once a year, in the spring.
Other Canadian guidance lands in the same place. The Intact Centre on Climate Adaptation at the University of Waterloo puts "Clean out backwater valve" on its spring and fall checklist, beside testing the sump pump and its backup power. The Insurance Bureau of Canada, writing with the Institute for Catastrophic Loss Reduction, says to maintain it at least once a year. The City of Toronto's basement flooding program page tells its residents to maintain and regularly inspect the valve according to the manufacturer's directions. That is Toronto's advice, but it holds anywhere.
Our suggestion: a quick check of your own in spring and fall, plus one professional inspection and cleaning a year. Your valve's manual still comes first, because models differ.
Time it for the thaw and storm season
The Region of Durham notes that basement flooding happens especially during heavy rain storms or during snow melt. So do the spring check in late winter, before the snow starts to go. Do the fall check once the leaves are down. The IBC points out that heavy precipitation can happen at any time of year, so a look after a big storm makes sense too.
Test the sump pump while you are at it. Our spring sump pump maintenance guide walks through it.
A homeowner's backwater valve maintenance checklist
These steps follow the Government of Canada's cleaning instructions and the published maintenance steps from one Canadian valve manufacturer. Check them against the manual for your own valve.
- Put on rubber gloves and safety glasses. Ask everyone in the house not to run water while you work.
- Lift the lid of the access box (the inspection chamber) in the basement floor. Many valves have a clear top, so you can see inside before you take anything apart.
- Remove the cleanout cap and shine a flashlight inside. Look for debris and grease on the valve body and the flap or gate, including underneath it.
- If you find buildup, flush it clean. The federal guide suggests hot, soapy water for stubborn grease.
- Make sure the flap or gate moves freely. Look at the seals and gaskets for cracks or wear. On some valves the gate seals against an O-ring.
- Put the cap back and tighten it securely. The Government of Canada warns that backwater valves can fail if the cleanout cap is not secure.
- Close the access lid and keep the spot clear. No storage boxes on top, and no flooring laid over it.
Then jot down the date and what you saw, and snap a photo. It takes a minute, and you will have a record if anyone asks.
What not to do
Never remove the flap or gate, and never prop or tie it open. A valve that cannot close gives you no protection, and you may not find out until sewage is on the floor. If you think the valve is slowing your drains, call us instead.
Do not leave the cap loose, for the reason above. And go easy on water while the valve is closed. In a storm, a closed valve also stops your own wastewater from leaving. The federal guide advises against showers, baths, the dishwasher and laundry during heavy rain, and Toronto's page warns that water from fixtures used while the valve is closed will back up into the home. A valve alarm tells you when it has closed.
Finally, keep fat, oil and grease out of the drain. The Region of Durham lists this as a way to lower your risk of sewer backup, and grease is exactly what you end up flushing out of the valve.
Signs the valve needs professional attention
Book a visit if you notice any of these:
- The flap or gate sticks, or will not close flat against its seat.
- A seal or gasket is cracked or worn, or a float looks damaged.
- Buildup will not flush clean, or keeps coming back.
- The cap will not tighten, or the clear lid is cracked.
- Sewage came up through a floor drain even though you have a valve.
- Several drains are slow at once. The Region of Durham says slow drains can be caused by root infiltration, a damaged connection pipe or a sewer main backup, and should be inspected and repaired.
- You cannot find the valve, or the access box is buried under a finished floor.
That is what our annual backwater valve inspection and cleaning is for. Our notes on basement flood prevention valve checks list what to tell the office when you call. If sewage is coming up through a floor drain right now, the City of Oshawa directs residents to the Region of Durham Works Department depot at 905-655-3344. The Region's after-hours emergency line is 905-576-9991. Our own line, (905) 576-3043, has a live operator 24/7.
Upkeep, the Region's loan program and your insurance
The Region of Durham runs a Basement Flooding Loan Program for owners whose basement flooded from a sanitary sewer backup. It offers an interest-free loan of up to $3,000 toward an approved backwater valve and sump pump, repaid on the quarterly water and sewer bill. The program notice is blunt about upkeep. It states that "homeowners are responsible for the ongoing care and maintenance of the backwater valve and sump pump, as well as the initial purchase cost." Applicants also sign this declaration: "That I will maintain the backwater valve and sump pump to ensure that it remains functional at all times."
So if you used the loan, backwater valve maintenance is part of the deal you signed. Program terms change, so confirm them with the Region. Our guide to plumbing rebates and subsidies in Durham Region covers where else to look.
On insurance, the IBC says damage from sewer and drain backups is typically not covered by a standard policy. Most insurers offer it as optional coverage, and the IBC adds that some insurers offer incentives for backwater valves or sump pumps. Ask your broker if your policy includes sewer backup coverage, and if your insurer asks about a backwater valve. Keep your installation paperwork with your dated notes so you can answer questions quickly.
Next step: book your annual inspection
If you would rather hand off backwater valve maintenance, Hayes Plumbing offers annual backwater valve inspection and cleaning across Oshawa and Durham Region. No valve yet? Our backwater valve installation service covers existing homes, and we handle the permit and municipal inspection. You get the invoice and inspection record that loan or insurance paperwork may ask for. We can also pair the valve with a sump pump and battery backup. Call (905) 576-3043 or book a visit online.