Backflow Valves - Bosco Home Services

One of the risks of heavy rainfall and overland flooding is sewer backups, which occurs when a blockage or break arises in the sewer main and water gets pushed into your home through your sewer or drainage system. This can result in basement flooding and thousands of dollars of water damage to your home.

Issues related to pressure changes and inclement weather can make hazardous waste flow backward into your drain pipes and cause sewage to spill out of your sinks, toilets, and showers. In extreme cases, it can even cause a flood.  It’s one thing to have to deal with rainwater in your basement…but wastewater backup is nothing short of disastrous.

Fortunately, there is a way to prevent sewage from ever entering your home. A backflow valve (also called a backwater valve or backflow prevention valve) is a preventative device that ensures that wastewater doesn’t flow into your home and protects your home from sanitary sewer line backup.

Whether you need one installed or existing unit repaired, replaced, or upgraded, we are here to help.


Your home’s plumbing system is designed to allow wastewater to flow in one direction: out of your house and into the municipal sewer system. Normally, the force of gravity is enough to prevent water from moving in the opposite direction.

But if the main municipal sewer line becomes overloaded (due to very heavy rainfall or overland flooding) the pressure can force wastewater to flow back up and enter your home through the floor drain, sink, tub or toilet.

A backflow valve is specifically designed to stop this from happening. The valve has a small, one-way flap that lets water flow out of your plumbing system. If water starts moving the opposite way, it will lift the flap and firmly shut so no water can enter or leave. The valve works automatically and requires no electricity, so it will continue to operate during a power outage.

When the water level drops, the flap will drop and allow water to exit your plumbing system again.


Having a backflow device in place can mean the difference between keeping dry or dealing with a potentially disastrous situation. Backflow valves can be installed in new homes or retrofitted into older ones.

You may need a backflow device installed if you:

     Live in a mature area with original city piping

     Live in an area with a lot of rain or poor drainage

     Live in a condensed/high population area

Call us to learn more about installing a backwater valve in your home.


     Water leaking out of the drain in your basement

     Stains around the drain area

     Strong odor coming from the drain


Like all parts of your plumbing system, a backflow valve does require some maintenance to keep it running smoothly. Backflow valve maintenance involves:

     Cleaning out the valve to remove debris

     Testing to ensure all moving parts are functioning properly

     Inspecting the flow of water out of your home

     Checking the seal around the backflow valve lid

With proper maintenance, your backflow valve should last many years. Learn more abou our stress-free plumbing service plans that start at just $6.95/month.


With overland flooding on the rise, many municipalities are now offering basement waterproofing and flood prevention subsidies in the Greater Toronto Area. These amounts often cover the cost of installing a backflow valve in your home. The City of Toronto, Peel Region and Halton Region are among the regions where these subsidies may be available.

Some home insurance companies require that you have a backwater valve installed in order to claim coverage for water damage, or offer a policy rebate for homeowners who have one installed.




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We are ready to help with all of your Plumbing or HVAC needs.