My Backwater Valve installations Meet & Exceed All Insurance and Code Requirements

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Full port normally open backwater valve

A normally open backwater valve may be installed in your main drain provided certain criteria are met; i.e. distances from existing outlets in order to provide laminar flow.

A normally open backwater valve will provide for the free flow of air in your plumbing system as well as protecting you from sewer backup.

A normally closed backwater valve does not provide for the free flow of air in the plumbing system and may not be installed in the main line, however they may be used in the branch line serving the main drain.

Our certified plumbers can assist you in determining what type of valve you may need for your specific application.

A city permit and a plumbing inspection will be required on all backwater valve installations.

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​What is the advantage of a mainline back water valve?

The primary advantage of installing a mainline backwater valve (bwv) is that your entire plumbing system is protected from a municipal sewer backup with just the one mainline valve, instead of having separate bwv on each individual building drain branch.

Because bwv have moving parts the plumbing code dictates they be readily accessible for cleaning, repair and maintenance which requires them to have an access box. Since most branchline bwv serve a bathroom group they are generally placed within the bathroom they serve and this creates problems due to the fact they are usually covered over with tile, lino or other flooring products.

The mainline bwv is installed where the sewer enters the house which is usually a more  convenient place for easy access.

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​Do I have a mainline back water valve (bwv) and how do i find it?

If your home was built prior to 1998 chances are you do not have a mainline bwv installed in your building drain(you hear the terms building drain and building sewer, they are the same line, but within your house it is called the building drain and once it leaves the house its called the building sewer). The mainline bwv was invented in the city of Edmonton Alberta in 1997 and was approved for use in building drains in Oct 1998 through a change to the national plumbing code. This change allowed for the use of a single normally open bwv and eliminated the need for individual bwv on each building drain branch. However, your home may have been retrofitted with one prior to you purchasing your property.

A mainline bwv will be located downstream of the last building drain branch. Usually within 2-4 feet of the foundation wall where the building drain exits the house. There will be a recognizable cleanout cover in the floor.

If you cant find where the building drain exits the house you may try locating the main water shutoff valve and water meter. Since the water line and building drain/sewer in most cases are in the same trench.

Failing that you can call us at Crowfoot Plumbing, we have sewer cameras and locating equipment.