What is a Backwater Valve?
A backwater valve ensures that sewage can’t flow from the city sewers into your house. If the city sewers in your area get clogged or overflow, a stopper will close and prevent any sludge from backing up into your home.
For rock-solid reliability and value, we love Mainline Fullport backwater valves. Our Knights in shining armour will provide you with exceptional service- from advice to installation, to guaranteed workmanship. The Knight team of professionals has the solution.

How does a backwater valve protect me?
Backwater valves are there to protect you from flooding- it is the barrier keeping the city sewage from backing up into your home. Unfortunately, nothing can guarantee that you’ll never experience a flood. If one of our rivers overflows its banks and there’s water over the surface of the ground, no valve can stop that. It also cannot prevent clogs inside your home. A backwater valve does one job perfectly: it prevents flooding due to overloaded sewers.
Who Needs a Backwater Valve?
If you have a home on higher ground, you may still be at risk: homes on high ground are not necessarily exempt from needing backwater valves. It’s all about how full the sewers are in your area, and if your home is situated above the grade of the main sewer system.
A backwater valve can technically be installed in any home. However, the drainage slope of your home’s sewer line needs to be at least ¼” per foot. Otherwise, you may need to flush it out once a week. For some people, it’s worth it to avoid ever having to deal with a basement full of sewage. We will do an assessment and let you know what the pros and cons of your situation are.
In older neighbourhoods (pre-1960s) the sewage and storm drains are the same, and one backwater valve will work. In newer areas with separate storm and sewage lines, you may need two.

Backwater Valve Maintenance
A periodic look through the window on the top should tell you if the valve has floated or not (if it’s spring or there’s lots of heavy rain you should check daily). If the valve has floated it means the level of water in the sewer is high. You will need to stop using your water and toilets and call us.
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Over 40 years of service
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Backwater Valve Service Area
We provide backwater valve services to Calgary, Alberta and its surrounding areas:
- Cochrane
- Airdrie
- Langdon
- Chestermere
- Okotoks
- DeWinton
- Bragg Creek
- Deer Ridge
- Willow Park