Backwater Valves
Backwater valve installation stops city sewer water from coming up your basement floor drain or shower in a heavy storm. It is $2,600 plus HST installed, and in Halton Region and the County of Brant a municipal subsidy can pay a large share of it.
New Dundee, Wilmot Township, Kitchener, Waterloo, Cambridge, Guelph, Milton, Halton Hills, Acton, Rockwood and Georgetown, and parts of the County of Brant
Why basements flood from the drain
In a heavy storm, a lot of rain ends up in the sewer. Much of it comes from homes where downspouts, weeping tiles or sump pumps send rainwater into the sewer instead of onto the yard. When that collected storm water gets in, it overwhelms the system: the sewer fills up and comes under pressure, and the water looks for the easiest way out. In a lot of homes that is the basement floor drain or a basement shower: the lowest openings on the line.
A backwater valve works like a one-way door (a check valve) on your main drain. Water leaves the house as normal. When the sewer backs up, the flap closes and stays shut until the sewer level drops, then opens again on its own.
See it happen
Press a button to switch. The pictures play in a loop.
Illustration by Einwechter Plumbing & Heating.
How we install it
The valve goes on your main drain inside the house, near the front wall, where it can be reached for cleaning.
Subsidies
Halton Region and the County of Brant both pay part of the cost of a backwater valve. Checked October 2026.
Halton Region
50%, up to $1,600
Halton homes on municipal sewer, including Milton, Halton Hills, Georgetown and Acton. The valve goes inside and weeping tile must be disconnected. Claim within one year, once per property.
Halton Region
100%, up to $6,500
Halton homes. Often done together with a backwater valve.
County of Brant
50%, up to $3,000
County of Brant homes built before 2012. Proof of a flood insurance claim is required. $5,000 lifetime maximum per property.
Kitchener, Waterloo, Cambridge
None at this time
We checked the city and regional programs in October 2026 and did not find one.
Programs change and some close when the money runs out, so check the official page before you book. Every program we found across our area is on our plumbing and water rebates page.
For subsidy applications only
$600 + HST
Only if you’re applying for the Halton subsidy
Not applying for a subsidy? You don’t need an assessment. We just install the valve for $2,600 plus HST, as priced below.
If you are applying, Halton Region won’t pay its subsidy unless it has proof, before the work starts, that no storm water drains into your sewer. That means downspouts, weeping tiles and sump pumps. Halton accepts an assessment by a licensed plumber. Some older Halton homes also qualify for a drainage survey from the Region.
We come out, check the house and write it up. You get a written report before any work is done. It covers what Halton asks for: whether weeping tiles or outside drains run into the sewer, where your sewer pipe runs and what shape it’s in, where the downspouts drain, any backwater valve already in place, and your sump pump and where it discharges.
The $600 is not added to your price. It’s credited in full toward your backwater valve when the valve is installed within 90 days of the assessment, so the valve and the assessment together are still $2,600 plus HST.
Backwater valve
$2,600 + HST
Backwater valve cost
$2,600 plus HST covers the whole job, from the camera inspection to the new concrete and access lid. You get the price in writing before we start.
Groundwater coming in through the walls or floor is a different problem. That one is solved with a sump pump, and most homes are better off with both.
Locally owned since 2018
Questions we get asked
A backwater valve is $2,600 plus HST installed. That includes the camera inspection, locating the drain, cutting and digging, the valve and tie-in, and the new concrete with an access lid. No assessment is needed unless you’re applying for a subsidy.
In Halton Region, yes: 50% up to $1,600, plus up to $6,500 for weeping tile disconnection with a sump pump. The County of Brant pays 50% up to $3,000 for homes built before 2012, with proof of a flood insurance claim. See every rebate in our area.
Only if you’re applying for the subsidy. Without a subsidy, there’s no assessment: the valve is $2,600 plus HST installed. If you are applying, then before the valve goes in, Halton needs proof that no storm water drains into your sewer. Our plumbing and drainage assessment is $600 plus HST. It includes the site visit, a written report, an estimate, camera inspection and drain locating, and help with your application. The $600 isn’t added on top. It’s credited in full toward your backwater valve when the valve is installed within 90 days, so the total stays $2,600 plus HST.
Keep it to a minimum. While the flap is shut, water from your own sinks, toilets and laundry cannot leave the house either. Once the sewer level drops, the valve opens and everything drains normally.
Check it once a year. Open the access lid and make sure the flap moves freely and nothing is caught in it.
No. A backwater valve keeps sewer water from coming back in through your drains. A sump pump removes groundwater that collects around the foundation. They solve different problems.
Backwater Valves
Book a time. We will look at your drain, give you the price in writing, and walk you through the subsidy if you are in Halton or the County of Brant.
CALL US! 548-255-2662
