How to prevent a sewer backup

What is a sewer backup?

If the sewer pipe gets clogged or damaged, it blocks the normal flow of water into the municipal drain. And that means raw sewage can back up through the floor drain.

Is your home at risk?

Some signs of a sewer drain clog:

• Several plumbing fixtures are clogged or drain slowly
• The toilet clogs easily or makes gurgling noises when flushing
• The washing machine doesn’t drain or backs up into the toilet or bathtub

Don’t wait too long to have these problems checked by a licensed plumber.

How can you prevent a sewer backup?

Follow our tips to help prevent the expense and hassle of a sewer backup happening to you.

Clogged drains

• Don’t pour fats or oils down the drain as they can harden and clog drains.
• Don’t flush paper towels, wipes (including flushable wipes), diapers or feminine hygiene products down the toilet.
• Use your garbage disposal correctly. Always run water before and after to wash food waste down the drain.

Heavy rainstorms

• Disconnect downspouts, foundation drains and weeping tiles from the municipal drain.
• Add extensions to your downspouts so that rainwater runs away from the house onto the grass or garden instead of the driveway.
• Avoid non-porous landscaping like asphalt or concrete close to your house. Instead favour sod and flowerbeds that absorb rainwater.
• Consider installing rain barrels to collect rain and prevent runoff.

Get professional help

Install a backwater valve

Placed directly into the sewer line, a backwater valve automatically closes if sewage backs up from the main sewer. Contact a licensed plumber to install an approved backwater prevention valve. Ask your local municipality for information on approved backwater valves and available rebates. You might even save on your home insurance premium!

Install a sump pump

If your home is in a low-lying area or where flooding is likely, a sump pump will remove water that accumulates in the basement or crawl space. Depending on usage, a sump pump will last 10 to 15 years.

Check sewer drains

Get a professional to inspect the drain with a sewer camera to check for holes or obstructions like tree roots.

If a sewer backup happens to you

• Stay out of floodwater in your basement, especially if there are electrical outlets nearby.
• Don’t use any of the plumbing until the blockage has been fixed.
• Turn off power at the electrical panel, but only if you can reach it safely without walking in water. Call your electrical utility or a licensed electrician for help.
• Contact your local public works department or a licensed plumber to have them determine the source of the problem.

Are you insured?

Sewer backups in your basement can be dangerous to your health and costly to repair. Check your home insurance policy to see if you are covered in the event of a sewer backup.

A leaky roof plus heavy rains can add up to big trouble. Would you know who to call first if your home had water damage? Go to Water damage: what every homeowner should know.

For more on this topic, visit:

Insurance Bureau of Canada: Backwater valve

Protect your home from basement flooding

Preparing for a natural disaster