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Sump Pump and Backwater Valve Cost in Ontario (2026): Replacing a Pump, Cutting a New Pit, Battery Backup, and the Toronto, Ottawa, Halton and Peel Subsidies Worked Out
Plumbing & Water
Sump Pumps and Backwater Valves: Two Cheap Machines That Stand Between You and a Wet Basement
Most flooded basements in Ontario towns come from one of two places: groundwater the sump pump did not keep up with, or sewage coming back up the floor drain from a city main that filled in a storm. A sump pump deals with the first and a backwater valve deals with the second. Both are a lot cheaper than a new basement floor. This page prices them and works out the city subsidies the way they actually pay.
The numbers
$1,200replace a sump pump in an existing pit, our default
$3,500new pit cut into the slab, our default
$2,800backwater valve retrofit, typical GTA job
80%of the invoice, up to each cap, in Toronto if you qualify
| Job | Installed range | Note |
|---|---|---|
| Replace a sump pump, existing pit | $450 to $1,800 | $1,200 default; low end is pump only |
| New sump pit, cutting the slab | $2,500 to $4,500 | $3,500 default |
| Complete sump system | $1,200 to $4,500 | pit, pump, discharge line |
| Battery backup pump | $300 to $1,600 | $900 default; AGM $600 to $1,100, lithium $1,100 to $1,800 |
| High-water alarm | $150 to $300 | |
| Backwater valve, inside through the slab | $1,000 to $3,500 | the usual retrofit |
| Backwater valve, outside in the yard | $2,400 to $4,800 | digging outside the foundation |
| Backwater valve, Toronto and GTA | $2,000 to $4,500 | typical $2,800, our default |
| Backwater valve, Ottawa | $1,800 to $3,800 | |
| Permit for the valve | $100 to $300 | varies by city |
| Plumbing assessment | $300 to $600 | Toronto subsidizes it, up to $500 |
October 2026, before HST. Where the water comes from in the first place, the weeping tile around the footing and how it drains to the pit, is on the weeping tile and sump pump page; this page does not repeat it.
Why Ontario prices are all over the map: the contractors and price guides we checked for this page quoted very different prices for the same job. A Barrie plumber said $700 to $1,800 to replace a sump pump, and a national home-services marketplace showed an average of about $2,045 for an installation in Barrie and about $5,500 in Toronto. For a backwater valve, a national renovation marketplace said $2,000 to $4,500 in the GTA, a Canadian building guide $1,500 to $5,000 in Toronto, and a national marketplace averaged about $6,000 in Toronto, likely with more work in it. A pump swap is not a new pit. Budget $1,200 for a pump and $2,800 for a valve, and get two or three quotes on the same written scope.
The Sump Pump: Replace It Before It Retires Itself
A sump pump collects the weeping tile water in a pit and throws it outside. It works hardest in the spring thaw and the big storms, exactly when the power is most likely to be out and the plumber most likely to be busy.
With a pit already there, replacing the pump is a short job, and $1,200 is a fair middle with a decent pump and a new check valve. With no pit, somebody cuts the slab, digs, sets a liner, ties in the tile and patches the floor: $2,500 to $4,500.
The Building Code (Article 7.4.6.3) wants a sump that takes weeping tile water to have a water- and air-tight cover. A sealed lid keeps out soil gas, smell and the occasional curious child. A loose plywood board on the pit is the cheapest upgrade in the house.
Where the water goes matters as much as the pump. Sump and weeping tile water never goes into the sanitary sewer, a floor drain or a laundry tub. The Code and municipal sewer-use bylaws both forbid it; thousands of basements doing that in one storm is how the city main backs up into everybody. In a house on septic the rule matters even more: the floor drain usually goes to the tank, and weeping tile water pumped into the tank can overload the leaching bed. It goes outside, onto the ground, away from the house.
Battery Backup and an Alarm: The Two Lines People Skip
A sump pump with no power is a very expensive bucket. In rural Simcoe County and Georgian Bay a house on a well loses its water in the same outage, so plan for both. See the rural power outage page.
- Put an alarm in the pit. $150 to $300 to know the water is rising before it reaches the carpet.
- Add a battery backup pump if the pit runs often. $300 to $1,600 installed depending on the battery; AGM units run $600 to $1,100.
- Test it twice a year. Pour a pail of water in the pit in spring and fall and watch it run. A pump you have not heard in two years is a rumour.
On our ICF builds the sump pit goes in with the rest of the under-slab plumbing, placed and inspected before the radiant tubing is covered and the slab is poured. After the pour, a forgotten pit is a jackhammer.
The Backwater Valve: A One-Way Door for Your Sewer
A backwater valve is a flap in the main drain. Water leaving the house pushes it open; sewage trying to come back from a surcharged city main pushes it shut. On a street with a history of backups it is worth far more than it costs.
Under the Building Code (Article 7.4.6.4), a valve is required on a fixture drain where the fixture is below the level of the adjoining street, and where a house is on a public sewer, fixtures below the upstream sanitary manhole cover must be protected. A backwater valve in the building drain must be a “normally open” type and serve no more than one dwelling unit. Normally open means the flap only closes when sewage backs up.
A retrofit inside the house means cutting the slab around the main drain, setting the valve with a removable cover at floor level, and patching. It needs a permit, and nothing gets covered before inspection. Toronto’s subsidy says in plain words not to cover the valve before inspection, and they do mean it.
Open the cover once a year and clear the flap. And while the valve is shut, the water you run in the house has nowhere to go either, so skip the laundry in a storm. The permit side is on the plumbing permit page.
The Subsidies, Worked Out If You Qualify
Several Ontario cities will pay part of the bill. None of it is automatic, and the money comes after the work, not off the invoice. Check before you book.
| Program | What it pays | Main conditions |
|---|---|---|
| Toronto Basement Flooding Protection Subsidy | 80 percent of the invoice, up to $6,650 a property | work on or after November 12, 2025; contractor with a City business licence; downspouts disconnected; permit; apply within 2 years |
| Ottawa Residential Protective Plumbing Program | 100 percent of the permit fee plus up to set maximums | older houses (sanitary valve: built before January 1, 2012); permit first; apply within 1 year |
| Halton Region | backwater valve 50 percent up to $1,600; weeping tile disconnection and sump 100 percent up to $6,500 | also downspouts up to $900, lateral lining 50 percent up to $4,000 |
| Peel Region | 60 percent of the backwater valve invoice up to $1,500 | |
| London; Hamilton | up to $1,800 for a valve; up to $2,000 for protective plumbing | check current status |
Toronto, if you qualify. Each item is 80 percent of its invoice up to its own cap. A $450 assessment pays $360 (cap $500). A $2,800 backwater valve with alarm would be $2,240, but the cap is $1,600, so $1,600. A $3,500 new pit and pump with alarm would be $2,800, cap $2,250, so $2,250. A $900 battery backup would be $720, cap $300, so $300. Invoice $7,650; subsidy $360 + $1,600 + $2,250 + $300 = $4,510; you pay $3,140. First come, first served.
Ottawa, if you qualify. The city pays the lesser of the cost or the maximum. An indoor sanitary valve at $2,800 plus a $200 permit: $200 + $1,000 = $1,200 back, you pay $1,800. A new pit with a battery backup pump at $3,500 + $900 = $4,400: up to $3,000 back, you pay $1,400.
Halton and Peel, if you qualify. The same $2,800 valve in Halton: 50 percent is $1,400, under the $1,600 cap. In Peel, 60 percent is $1,680, over the $1,500 cap, so $1,500.
Barrie, Orillia, Collingwood, Midland and Tiny: we found nothing. Call your municipality.
Questions people ask
How much does it cost to replace a sump pump in Ontario?
About $450 to $1,800 in an existing pit, before HST, with $1,200 a fair middle. A new pit cut into the slab is $2,500 to $4,500, and battery backup adds $300 to $1,600.
How much is a backwater valve in Toronto?
Usually $2,000 to $4,500 installed, typical about $2,800, plus a permit of $100 to $300. If you qualify, Toronto pays 80 percent of the invoice up to $1,600 a valve.
Can my sump pump drain into the floor drain or laundry tub?
No. Sump and weeping tile water may not go to the sanitary sewer, a floor drain or a laundry tub. It discharges outside, away from the foundation.
Does a backwater valve need maintenance?
Yes. Open the access cover once a year and clear debris from the flap, and avoid running water in the house while the valve is closed in a storm.
Do I need a backwater valve on a septic system?
The city-sewer backup a valve is built for is not the usual risk on a private septic system; the septic systems guide covers what goes wrong there. Ask your building department about your own house.
Price the job, then check the quote
The plumbing cost estimator puts the rest of a new house’s plumbing on one sheet; add the sump and valve lines from this page. The $99 review reads up to three quotes and tells you which left out the permit, the alarm or the patch. Next: the sewer line replacement page, and the drains, sewers and flood protection overview.
Sources and further reading
- Toronto Basement Flooding Protection Subsidy: the up-to-$6,650 program from May 1, 2026: amounts per device, the licensed-contractor rule and the permit.
- Ottawa Residential Protective Plumbing Program: the backwater valve and sump pump grants and the permit-fee refund.
- The 2024 Ontario Building Code: Ontario on the 2024 Code: in force January 1, 2025, the grace period to March 31, 2025, and the harmonization with the national codes.
