Basement Waterproofing Cost in Ontario (2026)
Waterproofing is priced by the linear foot of wall. So the first number you need isn't a price. It's how long your basement walls are.
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How much does basement waterproofing cost in Ontario? Published Canadian guides put interior waterproofing at about $70 to $230 per linear foot, and exterior waterproofing at about $100 to $300 per linear foot. For a 1,000-square-foot basement with about 140 feet of wall, that's roughly $10,000 to $32,000 inside, or $14,000 to $42,000 outside.
Below: interior vs. exterior prices, how to work out your own wall length, what pushes a quote up, and what's usually extra.
Interior vs. exterior waterproofing prices
| Interior waterproofing | Exterior waterproofing | |
|---|---|---|
| Price per linear foot | $70 – $230 | $100 – $300 |
| 140 ft of wall (about a 1,000 sq ft basement) | $10,000 – $32,000 | $14,000 – $42,000 |
| Digging outside | No | Yes, down to the footing |
| Wall stays dry | No, water is caught inside | Yes |
| Winter work | Yes | Depends on frozen ground |
| Our price per linear foot | From $85, plus HST, for the trench and concrete (drain, membrane and pump extra) | From $120, plus HST, for backfill and regrading (digging, membrane and weeping tile extra) |
Sources: HomeStars price guide (per-foot ranges); greenbuildingcanada.ca (whole-basement estimate). A Canadian cost guide notes that rates in large cities like Toronto sit at the mid to higher end because labour costs more.
How each system works: interior waterproofing and exterior waterproofing.
How do you work out your wall length?
Measure the outside of the house at ground level and add up the sides. A simple 30 by 40 foot rectangle has 140 feet of wall.
You may not need the whole perimeter. If water only comes in along one wall, waterproofing that wall alone can cost a quarter of the full price.
What pushes the price up?
- A finished basement. Drywall, framing and flooring along the walls come off and go back on.
- Depth. Deeper foundations mean more digging outside and more wall to cover.
- Obstacles outside. Decks, driveways, interlock, air conditioners and gardens along the wall.
- Tight access. Narrow side yards that an excavator can't fit into mean hand digging.
- Concrete block walls. These usually need exterior work, which costs more.
- Extras. A sump pump, a battery backup pump, or new weeping tile at the same time.
What's usually included, and what costs extra?
Ask every contractor what their quote covers. It often includes:
- The trench or excavation, drain pipe, membrane and gravel
- For interior systems, the sump pit and pump
- Concrete to close the trench, or backfill and grading outside
It often doesn't include:
- Removing and replacing drywall and flooring
- Restoring landscaping, interlock or decks
- A battery backup pump
- The warranty terms. Ask how long it lasts and whether it moves to the next owner.
Do you need full waterproofing at all?
Often not. A single crack costs a few hundred dollars to seal, and a flooding window well costs far less than a new drainage system. Find where the water gets in first. See leaking basement repair cost for prices by leak source.