Most homeowners pay $2,000–$7,000 to stop a foundation leak. Injecting a single leaking crack costs $250–$800, while interior drainage systems run $4,000–$17,000 and full exterior excavation and waterproofing $10,000–$18,000 (Angi, HomeGuide and Fixr data, as of October 2026).
Updated October 8, 2026. Source: Angi + 5 more. National US estimates.
Water coming through a basement wall, a floor crack or the joint where the wall meets the slab usually has one of two causes: a crack that gives water a path, or hydrostatic pressure from saturated soil pushing water through the concrete. The first can often be fixed from inside in a few hours; the second usually needs drainage.
This guide covers what each type of leak repair costs, a sample budget, and how to avoid paying for a full waterproofing system when a crack injection would do. If the whole basement takes on water, compare these prices with our basement waterproofing cost guide.
Average cost
Typical installed prices for foundation leak repairs, national averages as of October 2026:
| Scenario | Typical range | Notes |
|---|---|---|
| Single leaking crack, interior injection | $250–$800 | Epoxy or polyurethane; some contractors charge up to $1,500 for long cracks |
| Several cracks plus partial interior drain and sump pump | $2,000–$7,000 | Most common range for a recurring leak along one or two walls |
| Full interior drainage system | $4,000–$17,000 | Perimeter drain tile tied to a sump pump |
| Exterior excavation and waterproofing | $10,000–$18,000 | Membrane, drain tile and backfill; can top $20,000 |
Cost by repair method
| Method | Typical cost | Best for |
|---|---|---|
| Crack injection (epoxy or polyurethane) | $250–$800 per crack | Isolated cracks in poured concrete walls |
| Carbon fiber strips | $900–$2,000 per crack | Cracks with movement or slight bowing |
| Interior perimeter drain | $40–$120 per linear foot | Water at the wall-floor joint, high water table |
| Sump pump | $600–$2,500 | Required with interior drains |
| Interior sealant or waterproof paint | $1–$8 per sq. ft. | Dampness only, not active leaks |
| Exterior membrane | $3–$7 per sq. ft. | Applied after excavation |
| Regrading the yard | $500–$3,000 | Water pooling against the foundation |
Cost breakdown: materials, labor, permits and extras
Line-item estimate for stopping a recurring leak along one basement wall: injecting two cracks and installing about 30 linear feet of interior drain tied to a new sump pump. Ranges are national, as of October 8, 2026.
| Cost item | Typical range | What it covers |
|---|---|---|
| Crack injection (2 cracks) | $500–$1,600 | Epoxy or polyurethane, $250–$800 per crack |
| Interior drain, about 30 linear feet | $1,200–$3,600 | Cut slab, gravel, perforated pipe, new concrete; $40–$120 per linear foot |
| Sump pump and basin | $600–$2,500 | Pump, pit, check valve and discharge line |
| Permits | $75–$500 | Varies by town; often needed for drainage and electrical |
| Debris removal and cleanup | $130–$370 | Broken concrete and soil |
| Contingency (about 10%) | $250–$700 | Extra cracks found once walls are exposed |
| Estimated total | $2,750–$9,300 | Before any discounts or rebates |
If the leak comes from one crack and the soil drains well, the injection alone may solve it, which keeps the bill under $1,000.
What affects the price
- Number and length of cracks. Crack injection is priced per crack at about $250–$800, so three or four leaking cracks quickly approach the cost of a drainage solution. Long or wide cracks sit at the top of the range.
- Interior injection versus exterior excavation. Interior injection costs a few hundred dollars and needs no digging. Exterior work requires excavating down to the footing, which is why exterior waterproofing runs $10,000–$18,000; excavation alone is billed at about $50–$200 per cubic yard.
- Hydrostatic pressure and soil. When saturated clay or a high water table pushes water through the walls, sealing cracks is not enough and a drain and pump are needed. Sealants work only for dampness, not for water under pressure.
- Drainage additions. An interior perimeter drain costs $40–$120 per linear foot and needs a sump pump ($600–$2,500). Fixing gutters, extending downspouts or regrading ($500–$3,000) can reduce or eliminate the leak for less; see our sump pump installation cost guide.
- Access to the wall. Decks, patios, driveways, utility lines or a neighbor's house close to the wall make exterior excavation slower and more expensive, and restoring landscaping adds about $300–$1,000.
- Finished basement that must be opened up. In a finished basement, drywall, framing and flooring must be removed at the leak and replaced afterward. New drywall costs roughly $2–$6 per sq. ft. and flooring $4–$15 per sq. ft., on top of the leak repair.
Ways to save
- Clean gutters and extend downspouts at least several feet from the house before paying for anything else; many basement leaks are roof water dumped next to the foundation.
- Ask for a quote on crack injection alone if the leak is limited to one crack in a poured wall. A full perimeter system is not always needed.
- Get at least three written quotes, and compare price per linear foot of drain, the pump model and the warranty length.
- Repair leaks before finishing the basement. Opening finished walls adds drywall and flooring costs to every future repair.
- Check whether your city or water utility offers rebates for backflow valves, sump pumps or downspout disconnection; some flood-prone towns do.
- Have a structural engineer look at horizontal or widening cracks before sealing them; covering a structural problem only delays a larger bill.
How to get an accurate quote
Get at least three written quotes from licensed waterproofing or foundation contractors. Give each the same information:
- Where the water enters (a specific crack, the wall-floor joint, window wells or the floor), when it happens (heavy rain, snowmelt, year-round) and how much water.
- Wall type (poured concrete or block), whether the basement is finished, and access around the outside of the house.
- Ask each bidder to specify the method, linear feet of drain, pump model and backup, permits, cleanup and the warranty, and whether it is transferable.
FAQ
Can I seal a leaking foundation crack from the inside?
Yes, for most cracks in poured concrete walls. Interior epoxy or polyurethane injection fills the crack through its full depth and costs $250–$800 per crack. It does not help when water comes through block walls or the wall-floor joint under pressure.
Is interior or exterior foundation waterproofing better?
Exterior waterproofing stops water before it reaches the wall, but costs $10,000–$18,000. Interior drainage manages water that gets in and is cheaper, so it is the most common fix for existing homes.
Does homeowners insurance cover a foundation leak?
Usually not for seepage or gradual leaks. A sudden event such as a burst pipe may be covered, and groundwater flooding generally requires flood insurance.
For the big picture, start with our complete foundation repair cost guide.
Related cost guides
Sources
- Angi — How Much Does Foundation Repair Cost? (updated Aug 3, 2026). Checked October 8, 2026.
- Angi — How Much Does Basement Waterproofing Cost? (updated Jul 20, 2026). Checked October 8, 2026.
- HomeGuide — How Much Does Foundation Leak Repair Cost? (2026) (Feb 5, 2026). Checked October 8, 2026.
- HomeGuide — How Much Does Basement Leak Repair Cost? (2026) (Feb 6, 2026). Checked October 8, 2026.
- HomeGuide — How Much Does Basement Waterproofing Cost? (2026) (Jan 23, 2026). Checked October 8, 2026.
- Fixr — How Much Does Basement Waterproofing Cost? (updated Feb 6, 2026). Checked October 8, 2026.
Prices are estimates and vary by location and provider. See our methodology and editorial policy. Browse all foundation & water cost guides.