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Spring Sewer Backups

How a Backwater Valve Can Save You Tens of Thousands of Dollars

It will be spring in Calgary soon enough, and Calgary plumbers know what to expect — flooded basements. We’re not talking about leaky foundations. We specifically mean sewage backup from the main line, which happens when spring run-off overwhelms city sewer lines.

When the System is Overwhelmed

Those most at risk are residents of older communities in Calgary, but it can happen anywhere, even on an acreage. It goes like this: as snow melts around the city, and the weather turns rainy, the volume of water in the city’s sewage system swells drastically. Debris, such as fallen trees or branches may exacerbate the problem, causing blockages, but even without these added blockages the sheer volume of water can overwhelm the system.


What happens next isn’t pretty. With too much water in the pipes, the excess has to go somewhere. The outgoing pipes from homes along a street, which tie in to the sewer system, become escape routes for the extra sewage coming through the city drain systems. This mix of run-off and regular, everyday sewage is pushed back into the home via the drainage pipe that is meant to take your effluent out and into the city’s system.

Yes, this means a basement full of sewage. We can say with confidence that nobody wants that.

Waist-Deep Water in the Basement

A couple of years ago, one of our clients in the Fairview area of Calgary (an example of a neighbourhood just the right age to be vulnerable to this issue) experienced this unfortunate fate. They called us in the middle of the night for an emergency plumbing call. It had just stopped snowing and had started to rain. Fallen trees around the city had blocked the sewers, and the old pipes along the street couldn’t handle the swelling water levels and extra stress of the blockage.

When we arrived at the home, all the neighbours had their lights on as well — it seemed everyone was having the same issue. This is how it often goes with mainline sewer backup. By the time we got into the house, a 3-level split, the water in the basement was up to waist-level. Keep in mind, this was sewage!

The damage ruined their entire basement. We ended up replacing their furnace and hot water tank, and we did install a backwater valve for them in the end, as well.

Older Neighbourhoods at Risk

Though it’s possible for any neighbourhood to encounter this messy issue, older neighbourhoods are more vulnerable. This is because when the infrastructure was first put in place, it was designed to accommodate a certain number of homes. As more and more homes are built in Calgary, the system needs to serve this great number of residences. Lines in the older neighbourhoods become outdated and are less able to handle the input.

How a Backwater Valve Prevents Flooding

This isn’t an inevitable fate. For about 1/40th-1/50th of what it would cost you to clean up such a calamity (bills can run up to $50,000), you can have your qualified plumber install a backwater valve where your sewage line joins the main city line. This check valve will close in the event of a back-up, creating a dam and preventing expensive damage to your home.

Springtime should be about getting outdoors with your family, firing up the barbecue and enjoying your home and yard. Don’t risk spending your time cleaning up a smelly mess. Having a backwater valve installed protects your home from springtime sewage backup.

George Pinel
George Pinel

These blog posts are brought to you from George Pinel & the Instant Plumbing team.

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