Backwater Valves & Sump Pumps

A backwater valve and a sump pump solve two different problems. A backwater valve sits on the sewer line and closes when sewage flows the wrong way, so a backup in the City main cannot come up through your floor drain, toilet or shower. A sump pump sits in a pit, collects groundwater from the weeping tile around the foundation, and pumps it outside.

The City of Calgary recommends installing a backwater valve on the sewer pipe or on basement fixtures, and a plumbing permit is required to install one. New houses built in the floodway, flood fringe or overland flow areas are required to have one. A backwater valve needs occasional cleaning and a check that it closes, so ask the installer to show you where it is and how to open it.

For sump pumps, the City's advice is to have a backup pump with battery or generator power, a check valve, and a moisture alarm, and to replace the pump every ten years or sooner. Do not use a backup pump powered by drinking water. The discharge should carry water well clear of the backfill around your foundation. Calgary's drainage bylaw allows weeping tile and sump water to go to the storm system, and it does not allow roof drainage to be connected to the weeping tile.

If sewage has already backed up, report it to the City: it can snake to the main to see whether the blockage is on private or public property. Before counting on a rebate, check the City's website: we could not find a current City subsidy for backwater valves.