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A wet basement threatens everything below grade — and anything you finish down there. Waterproofing costs $2,500 to $12,000 in 2026, averaging around $5,000, or about $3.50–$8 per square foot, with the method driving most of the price.
What you’re paying for
The cost depends entirely on the approach. Sealing a single crack is cheap. A full interior drainage system with a sump pump manages water that enters. Exterior excavation digs down to the foundation footing to seal and drain the wall from outside — the most thorough fix and the most expensive.
Cost by method
The table below shows typical pricing from a single crack injection to full exterior waterproofing.
Fix the cheap stuff first
Before any major system, address the source — it’s often free or nearly so. Extend downspouts away from the foundation, clean and repair gutters, and re-grade soil to slope away from the house. A surprising share of “wet basement” problems trace back to water dumping right next to the foundation, and these fixes can solve minor moisture for a few hundred dollars.
Interior vs. exterior
Interior systems are cheaper, less disruptive, and effective at managing water — the common choice. Exterior waterproofing is the gold standard (it stops water at the wall) but requires excavating around the house, so it’s reserved for serious, chronic problems. If you’ve got structural concerns too, see our foundation repair guide.
How to save on basement waterproofing
- Fix grading, gutters, and downspouts first — often the cheapest real fix.
- Choose an interior system unless the problem is severe.
- Get an independent assessment before committing to exterior excavation.
- Add a battery backup to your sump pump to avoid failures during storms.
| Item | Typical range | Notes |
|---|---|---|
| Crack injection (per crack) | $500 – $1,500 | – |
| Interior sealant / coating | $3.50 – $8 / sq ft | – |
| Interior drainage + sump | $3,000 – $8,000 | – |
| Exterior excavation & membrane | $8,000 – $15,000 | – |
| Sump pump (add) | $1,000 – $3,000 | – |
| Option | Typical range | Notes |
|---|---|---|
| Crack injection (single) | $500 – $1,500 | – |
| Interior sealant / coating | $3.50 – $8 / sq ft | – |
| Interior drainage + sump pump | $3,000 – $8,000 | Most common full fix |
| Exterior excavation & membrane | $8,000 – $15,000 | Most thorough; most expensive |
What affects the price
- Method Interior drainage manages water that gets in; exterior excavation keeps it out at the wall but costs far more.
- Severity & source A single crack is cheap; chronic flooding needs a full drainage system or exterior work.
- Basement size Priced partly per square foot, so larger basements cost more.
- Sump pump A sump pump (and backup) is usually part of a complete interior system.
Basement waterproofing cost by state
Where you live can change the price as much as the options you pick. Labor is a big part of the bill, and construction workers are paid more in some states than others. A typical basement waterproofing job costs about $2,900 to $14,000 in Hawaii (17% above the U.S. average). In Arkansas, it costs about $2,100 to $10,200 (15% below the U.S. average).
See the typical cost in all 50 states and D.C.
| State | Typical range |
|---|---|
| Alabama | $2,200 – $10,400 |
| Alaska | $2,900 – $13,800 |
| Arizona | $2,400 – $11,400 |
| Arkansas | $2,100 – $10,200 |
| California | $2,800 – $13,400 |
| Colorado | $2,500 – $12,000 |
| Connecticut | $2,700 – $12,800 |
| Delaware | $2,500 – $11,800 |
| District of Columbia | $2,700 – $13,000 |
| Florida | $2,300 – $10,900 |
| Georgia | $2,300 – $11,000 |
| Hawaii | $2,900 – $14,000 |
| Idaho | $2,400 – $11,300 |
| Illinois | $2,900 – $13,800 |
| Indiana | $2,500 – $12,100 |
| Iowa | $2,400 – $11,600 |
| Kansas | $2,400 – $11,400 |
| Kentucky | $2,300 – $11,200 |
| Louisiana | $2,300 – $10,800 |
| Maine | $2,500 – $11,800 |
| Maryland | $2,500 – $12,000 |
| Massachusetts | $2,900 – $13,800 |
| Michigan | $2,500 – $12,000 |
| Minnesota | $2,700 – $13,100 |
| Mississippi | $2,200 – $10,400 |
| Missouri | $2,600 – $12,200 |
| Montana | $2,500 – $11,800 |
| Nebraska | $2,400 – $11,300 |
| Nevada | $2,600 – $12,400 |
| New Hampshire | $2,500 – $11,900 |
| New Jersey | $2,800 – $13,700 |
| New Mexico | $2,300 – $11,000 |
| New York | $2,800 – $13,200 |
| North Carolina | $2,300 – $10,800 |
| North Dakota | $2,500 – $12,100 |
| Ohio | $2,500 – $12,000 |
| Oklahoma | $2,300 – $10,900 |
| Oregon | $2,800 – $13,200 |
| Pennsylvania | $2,500 – $12,100 |
| Rhode Island | $2,600 – $12,500 |
| South Carolina | $2,300 – $10,900 |
| South Dakota | $2,300 – $10,800 |
| Tennessee | $2,300 – $11,000 |
| Texas | $2,300 – $10,900 |
| Utah | $2,400 – $11,300 |
| Vermont | $2,400 – $11,600 |
| Virginia | $2,400 – $11,400 |
| Washington | $2,900 – $13,900 |
| West Virginia | $2,400 – $11,400 |
| Wisconsin | $2,600 – $12,500 |
| Wyoming | $2,500 – $11,900 |
These are numbers to plan with, not quotes. Each one is this guide's U.S. range, adjusted for what construction workers earn in that state. See every state cost guide or how we estimate.
Common questions
- How much does basement waterproofing cost?
- Most projects run $2,500–$12,000, averaging about $5,000. Interior systems are $3,000–$8,000; full exterior waterproofing runs $8,000–$15,000.
- Interior vs. exterior waterproofing — what's the difference?
- Interior systems (drainage + sump pump) collect and pump out water that enters — cheaper and less disruptive. Exterior systems excavate around the foundation and seal the walls to keep water out — the most thorough but most expensive.
- Will waterproofing fix the source of the water?
- Interior systems manage water, they don't stop it. Start with the cheap fixes — extend downspouts, fix grading so soil slopes away, clean gutters — which often solve minor moisture for little money.
- Do I need a sump pump?
- Most complete interior systems include a sump pump (often with a battery backup) to discharge collected water. It's a key part of keeping a basement dry.
- Is basement waterproofing covered by insurance?
- Usually not — gradual seepage and maintenance are excluded. Insurance may cover sudden water damage from a covered event, but not the waterproofing system itself.
- What are the signs I need waterproofing?
- Damp walls, efflorescence (white mineral deposits), musty smells, pooling water, and cracks that weep all signal water intrusion worth addressing before finishing a basement.
How we estimate: These are typical U.S. prices for materials and for hiring a pro to install them. We checked them against the 2026 sources listed below (see how we get our numbers). Your price depends on where you live, the size of the job and the materials you pick. Get two or three written bids before you choose a contractor.
Sources
We checked the prices on this page against 2026 numbers from these sources: