What Does Basement Waterproofing Cost?
Basement waterproofing costs $600 to $35,000, averaging around $10,000 for a comprehensive interior drainage system with a sump pump. The range is that wide because the solutions are genuinely different jobs, not different sizes of the same job. Sealing a crack and adding a sump pump is a targeted fix; a full interior-and-exterior system is a major undertaking. What you pay depends on the type and extent of the water problem and whether the approach is interior, managing water after it enters, or exterior, preventing entry at the source.
| Solution | Cost |
|---|---|
| Single crack injection | $300 to $800 per crack |
| Sump pump installation (new pit and pump) | $600 to $2,500 |
| Battery backup sump pump system | $1,500 to $2,500 |
| Interior perimeter drain tile | $60 to $120 per linear foot of wall |
| Interior drainage plus sump pump | $6,000 to $15,000 (average $10,000) |
| Exterior waterproofing | $15,000 to $35,000 (one wall $6,000 to $12,000) |
Cost figures on this page were checked against published pricing on August 25, 2026. How we source cost data.
Targeted Fixes: $600 to $2,500
Sealing a specific crack with polyurethane injection runs $300 to $800 per crack. Installing a window well drain or replacing a sump pump falls in the same band. A sump pump sits in a pit dug at the basement’s low point where entering water collects and switches on automatically to pump that water up and away from the foundation, so it does not stop water from entering, it removes it before it pools.
Targeted fixes are appropriate when water entry comes from a single identifiable source. They are not appropriate when the basement has generalized moisture, which indicates multiple entry paths or vapor transmission through the wall and slab.
Interior Drainage: $6,000 to $15,000
The most common comprehensive interior solution is a perimeter French drain, or drain tile, installed at footing level. A channel is cut along the inside edge of the basement floor and a perforated pipe run around the full perimeter, collecting water that infiltrates through the wall-floor joint and routing it to the sump pit. It gives water that gets in a defined path straight to the pump instead of letting it spread across the floor, and it never touches the yard.
Drain tile runs $60 to $120 per linear foot of wall, so a full basement perimeter with a sump pump lands at $6,000 to $15,000, averaging about $10,000. Interior sealing or coating on its own is a separate and much smaller line at $1,000 to $3,000, and it handles dampness rather than water under pressure.
Exterior Waterproofing: $15,000 to $35,000
Exterior waterproofing excavates a trench down to the footing around the affected walls, applies a waterproofing membrane to the exterior face of the foundation, installs a drainage board, and reinstalls a footing drain. It stops water at the wall rather than managing it after entry. Cost runs $100 to $300 per linear foot, from $6,000 to $12,000 for a single wall to $15,000 to $35,000 for the full perimeter. The excavation is what makes it both the most thorough option and the most disruptive, since it means working through landscaping, driveways, and any utilities adjacent to the foundation. (For more on this, see Basement Waterproofing Mistakes to Avoid.)
Interior or Exterior?
Exterior is the more permanent solution because it keeps water out of the wall entirely. Choose it when the budget allows, when the wall membrane has failed and the wall is actively wet, and when there is room to excavate without tearing out a driveway or major landscaping.
Interior drainage is the right call when excavation cost is prohibitive, when the basement is being finished and dryness can be achieved through interior management, and when the specific entry points can be handled with drain tile and a reliable pump. The tradeoff is that water is still entering the wall, and potentially affecting the wall’s long-term integrity, but it is being intercepted before it reaches the floor.
The most effective comprehensive approach combines both: exterior waterproofing to prevent entry, with interior drain tile and a sump pump to manage residual water. For homeowners who cannot justify the excavation, interior drain tile with a battery backup pump delivers a dry basement at much lower cost. (For more on this, see The Drawbacks of Basement Waterproofing: An Honest Look.)
What Else Moves the Number
Basement size, the severity and source of the water problem, and whether both interior and exterior work are needed all shift the total. Hydrostatic pressure is often what drives a project to the top of the range: when the water table or saturated soil around the foundation builds enough pressure to force water through the walls and floor, controlling it can require an interior system to handle what gets in plus exterior work to relieve pressure outside. That combination is what pushes a project to the $35,000 end. (For more on this, see Interior vs. Exterior Basement Waterproofing: Which Is Right?.)
Grading and outdoor drainage improvements and difficult site access add cost as well. Evaluate surface drainage corrections first, though: regrading, gutter extensions, and downspout routing often reduce or eliminate the need for a major waterproofing system.
Permits and Service Life
Interior drain tile may or may not require a permit depending on the jurisdiction, so confirm with the local building department. A sump pump discharging into the sanitary sewer rather than to grade almost always requires a permit, and most jurisdictions prohibit that discharge method outright. Exterior waterproofing with excavation typically requires a permit, and the contractor should pull all required permits as part of the project.
A properly installed interior drain tile system with a reliable pump lasts 20 to 30 years before the drain pipe may need cleaning or replacement. An exterior membrane lasts 10 to 25 years depending on membrane type and backfill drainage quality. A sump pump lasts 7 to 10 years. Contractor warranties typically run 10 to 25 years but vary significantly, so get the terms in writing and understand exactly what the remedy is if the basement leaks during the warranty period.
Before You Hire
Get at least two written quotes on equivalent defined scope, and expect the diagnosis to drive the price more than the square footage does. Ask what is causing the water, what the proposed system does and does not address, whether permits and restoration of excavated areas are included, and what the labor warranty covers. For any project over $500, get the scope in writing before work begins.
Frequently Asked Questions
$600 to $35,000, because these are different jobs rather than different sizes of one job. Targeted fixes such as crack sealing or a sump pump run $600 to $2,500, an interior drainage system with drain tile and a sump pump runs $6,000 to $15,000 and averages about $10,000, and exterior excavation with a membrane runs $15,000 to $35,000 for a full perimeter.
Exterior is more permanent because it prevents water from entering the wall rather than managing it afterward, and it is preferred when the budget allows and there is room to excavate. Interior drainage is preferred when excavation cost is prohibitive or access is blocked by a driveway or major landscaping, and it keeps the basement dry for $6,000 to $15,000 versus $15,000 to $35,000.
A targeted fix at $600 to $2,500. Polyurethane injection of a single crack costs $300 to $800, and a new sump pit and pump costs $600 to $2,500. These work when water entry comes from one identifiable source, not when the basement shows generalized moisture.
A larger basement, a more severe water problem, and needing both interior and exterior work. Hydrostatic pressure from a high water table or saturated soil often requires an interior system plus exterior work to relieve pressure, and that combination is what pushes a project to the $35,000 end. Grading work and difficult access add cost too.
Yes, evaluate it first. Regrading, gutter extensions, and downspout routing often reduce or eliminate the need for a major waterproofing system, and they cost a fraction of a $6,000 to $15,000 interior drainage installation.
It depends on the work. Interior drain tile may or may not require one, so confirm with the local building department. A sump pump discharging into the sanitary sewer almost always requires a permit and is prohibited in most jurisdictions. Exterior waterproofing with excavation typically requires one, and the contractor should pull it.
An interior drain tile system lasts 20 to 30 years before the pipe may need cleaning or replacement, an exterior membrane 10 to 25 years depending on type and backfill drainage, and a sump pump 7 to 10 years. Contractor warranties typically run 10 to 25 years, so get the terms and the remedy in writing.
Exterior waterproofing to prevent entry combined with interior drain tile and a sump pump to manage any residual water. If excavation is out of budget, interior drain tile with a battery backup sump pump at $6,000 to $15,000 achieves a dry basement for a fraction of the excavation cost, with water still entering the wall but intercepted before it reaches the floor.