Basement repair costs in Toronto span an enormous range, from a few hundred dollars for downspout extensions to six figures for a full basement lowering.
In Toronto in 2026, interior basement waterproofing costs$80 to $150 per linear foot and a full interior system$8,000 to $15,000. Exterior waterproofing costs$150 to $300 per linear foot and a full perimeter$15,000 to $35,000. Underpinning costs$350 to $800 per linear foot, with a full basement lowering running$75,000 to $150,000.
Everything below is a verified market range rather than a quote. We publish them because a homeowner with no reference point cannot tell a fair quote from a bad one, and that asymmetry is how people get taken advantage of in this trade.
Waterproofing
| Work | Toronto 2026 range |
|---|---|
| Interior membrane and drain channel | $80 to $150 per linear foot |
| Exterior membrane waterproofing | $150 to $300 per linear foot |
| Full interior drainage system | $8,000 to $15,000 |
| Full perimeter exterior | $15,000 to $35,000 |
| Crack injection, per crack | $450 to $1,100 per crack |
| Window well drain, per window | $500 to $1,500 per window |
The two-to-one gap between interior and exterior is real and reflects genuinely different work, not different margins. Which one your house needs is covered on the waterproofing cost page.
Drainage and flood protection
| Work | Toronto 2026 range | Subsidy |
|---|---|---|
| Sump pump installed | $650 to $4,000 | Up to $2,250 |
| Battery backup | $300 to $800 | Up to $300 |
| Backwater valve installed | $2,000 to $4,500 | Up to $1,600 each |
| Weeping tile severance and capping | Varies | Up to $400 |
| Home plumbing assessment | Varies | Up to $500 |
This is the only table on this page where the City contributes anything. What is and is not covered — and why "save up to $6,650" beside a waterproofing price is misleading — is set out onthe subsidy page.
Underpinning and basement lowering
| Work | Toronto 2026 range |
|---|---|
| Underpinning, per linear foot | $350 to $800 per linear foot |
| Full basement lowering, Toronto semi | $75,000 to $150,000 |
| 600 sq ft lowered 2 ft, all in | $62,900 |
| Geotechnical investigation | $2,500 to $5,000 |
| Structural engineering | $3,500 to $8,000 |
| Permits and management | $1,500 to $4,000 |
| New concrete slab | $6,000 to $12,000 |
| Helical piles, per pile | $1,200 to $2,000 per pile |
Underpinning is the hardest thing on this site to price-compare, because contractors quote in incompatible units. The full breakdown, including a worked example, is on theunderpinning cost page.
How to use these numbers
A range tells you whether a quote is plausible. It does not tell you whether the quote is complete, and incompleteness is the more common problem.
Two quotes at the same headline rate can differ by $20,000 in what they include. The questions that make quotes genuinely comparable are onhow to choose a waterproofing contractor.