05/09/2026
Hey everyone โ welcome to this week's episode of "How NOT to Call the Plumber!"
Over the past few weeks, we've been talking a lot about your sump pump and what's happening underground in your drains. This week, we want to tie it all together and talk about something that doesn't get nearly enough attention but could be one of the most important plumbing devices in your home: The backwater valve.
Here's the scenario that makes a backwater valve so important. During a heavy rainstorm, the city's sewer system can become completely overwhelmed. When that happens, the sewage that's supposed to be flowing away from your home has nowhere to go and can actually reverse direction, flowing back toward the lowest point it can find. In most cases, that's your basement floor drain or your basement toilet. The result is raw sewage backing up into your home (yuck). Not only is this gross, but itโs incredibly dangerous as well.
What exactly is a backwater valve you ask?
A backwater valve is a one-way gate valve installed on your main drain line. When water is flowing normally away from your house, the valve stays open. The moment it senses flow coming back in the wrong direction, a float in the device closes automatically, blocking the sewage from entering your home. It's a simple concept, but the protection it provides is enormous.
A few things worth knowing:
๐ ๐ผ๐๐ ๐ผ๐น๐ฑ๐ฒ๐ฟ ๐ง๐ผ๐ฟ๐ผ๐ป๐๐ผ ๐ต๐ผ๐บ๐ฒ๐ ๐ฑ๐ผ๐ป'๐ ๐ต๐ฎ๐๐ฒ ๐ผ๐ป๐ฒ. If your home was built before the mid-1980s, there's a reasonable chance a backwater valve was never installed.
๐ง๐ต๐ฒ๐ ๐ฟ๐ฒ๐พ๐๐ถ๐ฟ๐ฒ ๐บ๐ฎ๐ถ๐ป๐๐ฒ๐ป๐ฎ๐ป๐ฐ๐ฒ. A backwater valve that hasn't been checked in years can become stuck open, meaning it won't close when you need it most. We recommend having it inspected every couple of years to make sure it's working properly.
๐๐ป๐๐๐ฎ๐น๐น๐ฎ๐๐ถ๐ผ๐ป ๐ฑ๐ผ๐ฒ๐ ๐ฟ๐ฒ๐พ๐๐ถ๐ฟ๐ฒ ๐ผ๐ฝ๐ฒ๐ป๐ถ๐ป๐ด ๐๐ฝ ๐๐ต๐ฒ ๐ณ๐น๐ผ๐ผ๐ฟ ๐ผ๐ฟ ๐ฑ๐ถ๐ด๐ด๐ถ๐ป๐ด ๐ฎ ๐๐บ๐ฎ๐น๐น ๐ฝ๐ถ๐ ๐ผ๐๐๐๐ถ๐ฑ๐ฒ ๐๐ผ๐๐ฟ ๐ต๐ผ๐บ๐ฒ. We won't sugarcoat it. Installing a backwater valve means accessing your main drain line, which typically involves cutting into the concrete floor of your basement. It's not a weekend DIY project and it needs to be done by a licensed plumber. The good news is that while the plumberโs there, it's also a great opportunity to replace any other sections of underground pipes that are showing any issues at the same time. More on that kind of work in a future post as we head into the summer season!
As Iโve been mentioning in previous posts, the City of Toronto's updates to the Basement Flooding Protection Subsidy Program are now live, and backwater valve installation could be covered up to $๐ญ,๐ฒ๐ฌ๐ฌ, with the total subsidy cap across all eligible work rising to $๐ฒ,๐ฒ๐ฑ๐ฌ per property. These changes have just been implemented as of May 1st, which makes this the best time to look into it as a consideration!
That's it for this week! If you're not sure whether your home has a backwater valve or when it was last serviced, it's a great question to ask the next time you have a plumber in. Have a wonderful weekend and we'll see you next time! ๐