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Mainline Backwater Valves

There are few problems worse that sewage backflow into your home. These days, most of us use our basements for enjoying family time, exercising, and storage of important documents and mementoes. One sewer problem can take all that away, and leave you with a massive restoration bill of tens of thousands of dollars.

One simple device can prevent this situation: the Mainline Fullport backwater valve. At DS Plumbing we’ve used the Mainline Fullport backwater valve for years and we’ve gotten great results for our customers.

Mainline Fullport backwater valve


This 2005 Manning Innovation Award-winning design is still one of the most effective on the market today.

The award-winning, patented “normally open” gate design does not restrict flow to the sewer from your home.

Does not interfere with your plumbing’s venting system.

Makes it easy to inspect or even clear drain clogs thanks to handy clean out valve.

Clear top makes it easy to see if the valve has been engaged and a sewer overflow is in progress.

Now required for all new homes by the City of Ottawa.

CSA approved.

You can get a Mainline Fullport installed on both your main sewage line and your storm sewer line. Homes build before the 1960s likely have one line for both purposes.

How Does It Work?

This device doesn’t have a lot of working parts to go wrong.

Diagram how Mainline backwater valve works

The gate is fitted with floatation devices on each side. Should water from your sewer move back into your home, the water level will lift the valve and close if firmly. An O-ring ensures a complete seal. Direction of water flow does the rest.

Once the problem with the city sewer line is cleared, the water pressure that keeps the valve closed is released and the gate opens on its own.

Easy Maintenance

The Mainline is easy to care for. All you need to do is clean the flap once a year to ensure there’s no buildup and it can close easily. If you’re a PAWS maintenance program member, we can do that for you.

What Happens if the Valve is Floated Because of a Sewer Backflow?

If you can see that the valve is in the closed position, you should call the City of Ottawa at 311 immediately to have them look at your local sewer. You will also need to stop using the water in your home, as the waste will have nowhere to go.

While this is inconvenient, your home and its contents will be kept safe from sewage overflow.

Why Choose DS Plumbing to Install Your Mainline?

DS Plumbing believes in doing the job right: we’re not only plumbing experts, but we’re friendly, we clean up after the job, and we’re happy to answer any questions you may have.

Predictable pricing: full costs provided up front – including labour!

Multi-award winning service: read about our awards here.

100% satisfaction guarantee: if you’re not happy we’ll come back and fix it for free.

Saturday service: why lose a vacation day if you don’t need to?

Fully accredited: We’re accredited by the BBB and TSSA.

Call or Email to Discuss Your Needs

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