Summer Storms and Sewer Backups

Why it happens

In a heavy storm, water enters the sewer system faster than it can drain. Pressure builds, and sewage looks for the lowest opening, usually the basement floor drain.

Backwater valves

A backwater valve on the main sewer line closes when sewage flows backward. Check that yours is clean and its flap moves freely.

During a storm

If your backwater valve has closed, avoid running water in the house; wastewater can't leave until the valve opens again.

Lot drainage

Make sure downspouts discharge well away from the house and that the ground slopes away from the foundation.

Sump pits

If you have a sump pit, test the pump before storm season and check that its discharge isn't blocked.

Get help

If you've had backups before, see backwater valves and sump pits.

What to keep out of drains

Grease, wipes and paper towels catch on rough spots in older sewer lines and leave less room for flow when the system is busy. Keeping them out of drains helps your line cope during a storm.

After a backup

Wear gloves, keep children and pets away and clean affected areas with disinfectant once the line is clear. Take photos for insurance, and ask a plumber to check the line and the backwater valve so it doesn't happen again.

Keep a record

Note the dates of any backups and how heavy the rain was. A pattern tied to storms helps a plumber decide whether the answer is a backwater valve, a repair to your line or both.

More plumbing guides

• Prairie Cold and Your Pipes
• Locating Your Main Water Valve
• How to Check Your Hot Water Tank's Age
• Closing Up a Lake Cabin for Winter
• Plumbing Permits in Regina