The majority of properties have been built so that a blockage in the public sewer will not cause a sewage backup into the property.
However, some properties require the protection of a backwater valve in the owner’s drain line. These properties have been built so that the flood rim of the lowest plumbing fixture is lower than the cover of the nearest upstream manhole of the public sewer. The backwater valve is designed to automatically close, to prevent sewage from backing up into the building from a blocked public sewer.
If your property already has a backwater valve, it needs to be checked and maintained regularly.
If you have any plumbing fixtures lower than the street in front of your house, you may need a backwater valve.
If the street outside your house goes steeply uphill, you may need a backwater valve.
