Man looking shocked at his septic problems.

Springtime should be spent enjoying sunny afternoons and skipping through puddles in the great outdoors — not trudging through vile sewage backup in your basement. There’s only one direction sewage should be flowing and it is not back up into your home.

To keep things flowing smoothly, a backwater valve is your best bet.

During a super heavy rainfall, or if your home is located in a floodplain, a backwater valve is the main thing that will keep sewage in the sewer system where it belongs and prevent pools of, well, poo water, in your home.

Not sure how to tell if you have a backwater valve installed in your home? Read on to learn all about backwater valves, where to find them, how they work, and how you can take advantage of Edmonton’s backwater valve subsidy program should you need to retrofit your home.

What is a backwater valve?

Also called a backflow valve or a sewer backup valve, a backwater valve is designed to restrict the flow of sewage in one direction only — out of your home and into the sewer system. During heavy rainfalls or flood situations, municipal sewer lines can become overwhelmed, and water or sewage will try to escape in any direction possible, including back up into your home through the floor drain, toilets, shower, bathtub, sinks — basically anything plumbing related.

When installed correctly, a backwater valve prevents sewage from flowing backwards up your sewer line and wreaking havoc (and reeking) in your home. Newly constructed homes require backwater valve installation, but older homes that predate the change to plumbing code (since 1988) may not have one.

How does a backwater valve work?

A backwater valve is a one-way valve with a flap. Under normal conditions, the flap is open and allows water and sewage to exit your home. When water or sewage starts to flow back up the drain pipe, the flap closes and blocks the flow from making its way back into your home.

Tips for finding and maintaining your backwater valve

If you have an older home, you’ll want to confirm if you have a backwater valve and even if you have a newer home, it’s a good idea to familiarize yourself with the location of your backwater valve so you can check it and perform regular maintenance.

Backwater valves are usually located in the floor of your basement. If you know where to find your sump pump, the backwater valve is probably nearby. There may be a rectangular panel on top, but often the compartment itself is clear so that you can see inside relatively easily and the round cap can be removed.

In terms of cleaning and checking your backwater valve, there are a few simple things you can do yourself.

  • Wearing gloves and protective eyewear, carefully open the cap and check for debris every few months, particularly in the spring and summer.
  • Flush the valve with a bucket of water.
  • If debris doesn’t clear on its own, scrub the valve to clean it thoroughly.
  • When you’re done, be sure to secure the cap tightly.

What to do during a severe weather event

Edmonton may not have to worry about hurricanes or typhoons, but we’ve been known to experience a torrential downpour or two during the summer months. If you’ve got a backwater valve, you can rest a little easier knowing you’re protected from sewer backup, but there’s something really important to keep in mind.

If your backwater valve is hard at work keeping raw sewage from geysering back up into your home, you’ll want to hold off on things like running the dishwasher, doing laundry, or taking a long shower. This is because that handy little flap of your backwater valve is stopping the flow — in both directions. Wait until the storm passes and give the municipal sewer system a chance to recover before using your home’s plumbing.

Backwater valve installation is best left for the professionals

A licensed plumber can install a backwater valve and will ensure downspouts and foundation drains are properly disconnected. He or she can also install a sump pump at the same time, if required. Backwater valve installation requires an inspection and a permit, and is best left in the hands of a qualified professional.

The plumber will create an opening in the concrete floor of your basement, usually near the floor drain. Once they’ve dug down to the main sewer line, they will remove a portion of the line and insert the new backwater valve. A rectangular panel may cover up the opening in the floor.

The cost of retrofitting a backwater valve ranges from $1,000 – $2,000, but the City of Edmonton offers a Backwater Valve Subsidy program which can provide up to $800 for interior or exterior backwater valve installation for eligible homeowners.

Let us be your backup before things get backed up

At First Call, our professional plumbers can help keep things flowing properly with backwater valve installation and maintenance.

Learn more about our plumbing services or, if things have already gone down (or up) the pooper, call our emergency line 780-464-3337 and listen for the prompts to leave a message for the on-call technician. They will return your call and arrive at your home to get things working as soon as possible (overtime rates will apply).