The basement waterproofing cost in Ontario in 2026 depends mostly on the method. A single foundation crack sealed by injection from inside typically runs about $500 to $1,500. An interior drain tile system with a sump costs roughly $50 to $100 or more per linear foot, or about $7,000 to $15,000 around a typical house. Exterior excavation with a membrane costs roughly $100 to $350 per linear foot, often $15,000 to $25,000 for a full perimeter. These are typical published ranges, not quotes.
Every figure below comes from a price guide we read and link, and the sources do not always agree. Where they differ, we show the spread rather than pick one number.
Cost by method: the table
Most Ontario detached houses have between 100 and 150 linear feet of foundation wall. A 30 by 40 foot footprint is about 140 linear feet, which is the example size used in Project Landscaping’s 2026 Ontario cost guide.
| Method | Typical range | What the range is based on |
|---|---|---|
| Crack injection (interior, one crack) | About $500 to $1,500 per crack | OnPoint Masonry’s Ontario guide. RCC Waterproofing’s price list shows $50 to $650 for internal crack repair, depending on crack size |
| Interior drain tile and sump, basic | $50 to $80 per linear foot | Project Landscaping, basic interior drainage |
| Interior drain tile, full perimeter with membrane | $70 to $120 per linear foot, about $7,000 to $15,000 for a 140 foot house | Project Landscaping; OnPoint gives $50 to $100 or more per foot |
| Interior system with backup pump | $100 to $180 per linear foot | Project Landscaping, premium tier |
| Exterior excavation and membrane | $100 to $350 per linear foot | OnPoint gives $100 to $250 or more; Project Landscaping gives $150 to $350 |
| Exterior, full perimeter | About $15,000 to $25,000 for a 140 foot house, up to about $35,000 | Project Landscaping |
| Exterior, one problem wall | About $5,000 to $15,000 | OnPoint |
| Sump pump installation | $500 to $3,000 | RCC gives $500 to $3,000; Project Landscaping gives $800 to $2,800 |
| Battery backup sump pump | $1,500 to $3,500 | Project Landscaping |
| Backwater valve | $1,500 to $3,700 | Project Landscaping |
Treat the table as a way to check whether a quote is in a sensible band. It is not a price list. Two of these sources are companies that sell the work, so their figures describe their own market, and a house with unusual conditions can land outside every range here.
What each method actually buys
Crack injection
A contractor fills a single crack with injected epoxy or hydraulic cement from inside the basement. It is the cheapest fix and, as the OnPoint guide puts it, often all a house needs when water comes through one crack in a poured concrete wall. It does not help if water rises through the floor, seeps along the wall to floor joint, or comes through many points in a block wall.
Interior drain tile
The crew cuts a trench in the basement floor along the inside of the walls, lays perforated pipe in gravel, and slopes it to a sump pit. A pump lifts the water out. Often a dimpled membrane goes on the wall so seepage runs down behind it into the new drain. The water still reaches the wall, but it is caught and removed before it spreads across the floor. Interior work does not need excavation outside, so it is faster, less affected by weather, and cheaper per foot.
Exterior excavation and membrane
The crew digs down the outside of the foundation to the footing, cleans and repairs the wall, applies a membrane, often adds a drainage board, replaces the weeping tile, and backfills. This stops water at the outside face of the wall. It costs more because of the digging, the disposal and the restoration afterward. It is often the choice when the basement is already finished and the owner does not want to open the floor and walls inside.
What drives the price
The same method can cost twice as much on one street as on the next. The published guides name these drivers.
Depth of the foundation
Deeper walls mean more digging and more membrane. Project Landscaping adds $20 to $50 per linear foot for each additional foot of depth on exterior work. Older houses with full height basements in Toronto and Hamilton are often deeper than newer builds.
Soil
Much of southern Ontario sits on clay. Project Landscaping says clay costs 25 to 50% more to excavate than sandy soil, because it is dense, holds water and is harder to dig. Clay also drains slowly, which is one reason water builds up against foundations after heavy rain and spring melt.
Access
A machine can dig along an open side yard in a few hours. A narrow gap between semi detached houses, a deck, an addition or a driveway can force hand digging. Project Landscaping says hand digging adds 30 to 50% to exterior costs. OnPoint names decks, additions and driveways as the conditions that push prices up.
Restoration
Someone has to put back the garden, the walkway or the interlock after an exterior dig. Project Landscaping puts landscaping restoration at $2,000 to $8,000 on top of the job. On interior work, restoration means the floor patch and any finished walls or flooring that came out.
What is in the quote
OnPoint notes that quotes differ in membrane quality, drainage board, weeping tile replacement, window wells and backfill material. A low number can simply mean a smaller scope. Ask each company to itemize so you can compare the same work. Also ask who pulls the permit. Project Landscaping gives Toronto permit costs of $200 to $600; confirm the current fee with the city before you rely on it.
City help with the cost
Some cities pay part of the cost of flood protection devices. These programmes cover backwater valves and sump pumps, not membranes or crack injection, and they have strict conditions. Read the city page before you sign a contract, because some conditions apply before work starts.
Toronto
The City of Toronto Basement Flooding Protection Subsidy Program pays up to 80% of eligible costs, with a cap on each item, for work completed on or after November 12, 2025:
- Home plumbing assessment: up to $500, one time only.
- Backwater valve: up to $1,600 per device, two devices at most.
- Sump pump: up to $2,250 for one device, plus up to $300 for a battery backup.
- Foundation drain severance and capping: up to $400.
The property must be a single family home, duplex, triplex or fourplex. You need a building permit for a backwater valve before work starts, the contractor needs a valid City of Toronto business licence, and you must apply within two years of the work with paid in full itemized invoices.
Hamilton
The City of Hamilton Protective Plumbing Program offers a grant of up to $2,000 for a backwater valve and other eligible works on a single family home with a basement, built before January 1, 2012. The full grant requires a contractor from the city’s pre-qualified list. With a contractor outside the list, the grant is at most $500 for a backwater valve. A separate loan of up to $2,000 covers eligible costs above the grant, including a sump pump installed with a backwater valve.
Ottawa and Mississauga
Ottawa runs a Residential Protective Plumbing program with rebates for sump pumps and backwater valves. We could not load the current rebate amounts from the city’s page today, so we do not state them here. Check the page directly. In Mississauga, ask the city and the Region of Peel what applies to your address before work starts.
What our boards show for Toronto, Mississauga, Ottawa and Hamilton
Our boards rank companies by Google rating and review count. They are data, not recommendations. These are the numbers from the September 2026 update.
| Board | Companies ranked | Median rating | Median reviews | Total reviews | Companies under 20 reviews |
|---|---|---|---|---|---|
| Toronto basement waterproofing | 20 | 5.0 | 100 | 3,989 | 0 |
| Mississauga basement waterproofing | 20 | 5.0 | 90 | 2,690 | 3 |
| Ottawa basement waterproofing | 20 | 5.0 | 56 | 1,394 | 5 |
| Hamilton basement waterproofing | 20 | 5.0 | 48.5 | 1,463 | 2 |
What this means when you choose:
- Ratings do not separate companies. The median rating is 5.0 on all four boards. Review count and what the reviews describe tell you more than the star average.
- Toronto is a deep market. Every one of the 20 ranked basement waterproofing companies in Toronto has at least 20 reviews, and the top company on the board has 867. You can be selective and still get three quotes.
- Mississauga is close behind. The basement waterproofing companies in Mississauga have a median of 90 reviews, and several appear on the Toronto board too, because they serve the whole western GTA.
- Ottawa and Hamilton are thinner. The basement waterproofing companies in Ottawa have a median of 56 reviews and 5 of 20 have fewer than 20. The basement waterproofing companies in Hamilton have a median of 48.5. A company with few reviews is not a bad company, but it gives you less evidence, so read the reviews that exist and ask for references on jobs like yours.
- Cracks and structure overlap. If the wall is bowing or the crack is wide and growing, the problem may be structural. Compare quotes from foundation repair companies in Toronto as well.
For every town we cover, start from the basement waterproofing trade page.
How to compare quotes
- Find the source of the water first. One crack, a leaking wall to floor joint and a high water table are three different problems with three different prices. A company that quotes a full perimeter system for one crack should explain why.
- Ask for price per linear foot and the total. Then check both against the ranges above.
- Compare the same scope. Membrane type, drainage board, weeping tile, sump pit, pump, backup, window wells, backfill and restoration should all be listed.
- Ask about the permit and the warranty in writing. Ask who applies for any permit, and what the warranty covers and whether it transfers to a new owner.
- Check subsidy conditions before you sign. In Toronto and Hamilton, the permit, the licence and the contractor list decide whether you get the money.
Frequently asked questions
How much does basement waterproofing cost in Ontario?
It depends on the method. Published 2026 Ontario price guides put a single crack injection at roughly $500 to $1,500, interior drain tile at about $50 to $100 or more per linear foot, and exterior excavation with a membrane at about $100 to $350 per linear foot. These are typical ranges, not quotes.
Is interior or exterior waterproofing cheaper?
Interior drain tile is usually cheaper because nobody has to dig down the outside of the wall. One Ontario guide puts a full interior system on a 140 foot perimeter at $7,000 to $15,000 and full exterior work on the same house at $15,000 to $25,000.
What makes a waterproofing quote go up?
Depth of the foundation, clay soil, poor access that forces hand digging, and landscaping, decks or driveways that must be removed and restored. Extra items such as a new sump pit, a battery backup pump or a backwater valve also add to the total.
Does the City of Toronto help pay for waterproofing?
Toronto’s Basement Flooding Protection Subsidy Program pays up to 80% of eligible costs, capped per item, for a backwater valve, a sump pump, a battery backup and foundation drain severance. It does not pay for membranes or crack injection, and it has permit and licence conditions.
How many waterproofing companies should I get quotes from?
Get at least three written, itemized quotes that use the same scope, so you can compare them line by line. Our boards list 20 ranked basement waterproofing companies in each of Toronto, Mississauga, Ottawa and Hamilton.