Backwater Valve

        I have a sewer backup!       I have a backwater valve.

                                        How can that be?

Required since 1988 in Edmonton, homes require a backwater valve to protect against sewer backup.

The earlier valves were use to protect the basement bathroom only, but starting in the early 2000’s mainline backwater valves have become the preferred choice. As the name suggests, installed on the main sewer line, this valve protects the entire house against sewer backup.

If you understand how they work, the problem is obvious but often overlooked by unsuspecting homeowners. A backwater valve is box about the size of a small microwave installed on the main sewer line under the basement floor and contains a flap on a hinge.  It is normally in the open position. This allows sewage to drain normally from the bathrooms, tubs, dishwashers etc.  out to the city sewer main under the street or back alley.

Great! So what’s the problem?

If we get a severe weather event or a torrential downpour , which can happen quite often during an Edmonton summer,  storm water can enter the city sanitary system. If severe enough, this can reverse the flow of sewage back into the home. Because of the design of the flap in the backwater valve the back pressure will cause the flap to automatically close, stopping the flow of sewage. “Phew” . It’s all good! Maybe or maybe not.  Read on…

During this weather event the mainline flapper valve is in the full closed position. Suppose an occupant decides take a shower, run the dishwasher or flush the toilet. Where is the water going to drain? It can’t compete with the backpressure forcing against the flapper valve from the city back up. The water will likely come up through the floor drain as it is the lowest fixture, usually located in the basement laundry room or furnace room.  Unfortunately,  you will now have to mop it all  up.

What can you do?

Homeowner behavior during a severe weather event can result in basement flooding, keep this in mind during the next severe weather event. What can you do? Inform all occupants to refrain from using the plumbing until the storm passes.

Backwater valves also require regular maintenance. The covers are removable, inspect for debris and buildup on the body, flapper and especially under the flapper. Flush clean. Also check the o ring for damage.

If you have an older home that does not have mainline backwater valve, they can be retrofitted. In certain circumstances a city rebate is available. For more information visit:



Do you need answers to your home repair questions?

Shell Busey is back on the radio with a new show. For those of you that remember, Shell was the DIY guru on 630 Ched in Edmonton in the 1990s.  The home discovery show was heard throughout Western Canada. The Ask Shell Show can now be heard on Roundhouse Radio 98.3 in Vancouver.  In Edmonton you can listen to the show live if you download the Radio Player Canada App on your Smartphone and search for Roundhouse Radio  9am to 10am  Saturday mornings.

Shell will be talking with guests, taking calls from homeowners and answering emails from homeowners submitted through and through Shell Busey’s HouseSmart Referral Network’s Facebook page.

It’s just that easy!