Methods from cheapest to most expensive
Waterproofing options by cost:
- Interior sealants and crack injection: $2,000 to $6,000
- Interior drainage with sump pump: $5,000 to $12,000
- Exterior excavation and membrane: $10,000 to $25,000
- Grading and gutter fixes: a few hundred to $3,000
Fix the source first
Many basement leaks come from poor grading, downspouts dumping near the foundation, or clogged gutters. Fixing drainage outside is cheap and often solves the problem before expensive interior or exterior systems are needed.