Home › Basement waterproofing cost
Basement Waterproofing Cost Calculator (2026)
Enter your basement size and choose a method. You get an itemized 2026 estimate for drain tile, exterior membrane, or sealer, plus sump pumps and add-ons.
| Item | Typical |
|---|---|
| Interior perimeter drain (drain tile) | $11,900 |
| Crack injection | $600 |
| Sump pump with new pit | $1,900 |
Installed prices including labor and materials. Your quotes can differ with site conditions.
Got a quote already? See if your waterproofing quote is fair →
Basement waterproofing cost by size
Waterproofing is priced along the walls, so the perimeter of the basement matters more than its square footage. Interior prices below include a sump pump with a new pit.
| Basement | Sealer only | Interior drain | Exterior dig |
|---|---|---|---|
| Small (20 × 25 ft, 90 ft perimeter) | $2,150 – $6,500 | $5,700 – $14,900 | $9,000 – $27,000 |
| Medium (30 × 40 ft, 140 ft perimeter) | $3,350 – $10,100 | $8,200 – $21,400 | $14,000 – $42,000 |
| Large (40 × 50 ft, 180 ft perimeter) | $4,300 – $13,000 | $10,200 – $26,600 | $18,000 – $54,000 |
Cost by method and component
| Item | Unit | Price range | Typical |
|---|---|---|---|
| Interior drain tile system | per linear ft | $50 – $130 | $90 |
| Exterior excavation + membrane + footing drain | per linear ft | $100 – $300 | $180 |
| Waterproof sealer or coating | per sq ft of wall | $0 – $10 | $10 |
| Crack injection | per crack | $350 – $1,000 | $600 |
| Sump pump with new pit | per system | $1,200 – $3,200 | $1,900 |
| Battery backup pump | per unit | $500 – $1,200 | $800 |
| Dimple wall membrane | per sq ft of wall | $0 – $10 | $0 |
| Regrade soil around house | per job | $1,000 – $3,500 | $2,000 |
Interior vs. exterior vs. sealer
Interior drain tile (most common)
The crew cuts a trench in the basement floor along the walls, lays perforated pipe in gravel, and re-pours the concrete. Water that comes through the wall or up from under the floor flows to a sump pump and out of the house. It costs about $90 per linear foot, takes 1–3 days, and needs no digging outside. Most jobs come with a lifetime warranty.
Exterior excavation
The crew digs down to the footing outside, cleans the wall, applies a waterproof membrane, and lays a new footing drain. It stops water from reaching the wall at all, which is why builders use it on new homes. On an existing home it means digging up landscaping, walkways, and sometimes decks. Expect around $180 per linear foot, more when access is hard.
Sealers and coatings
Masonry waterproofing paints and sealers cost $0 – $10 per square foot installed. They reduce dampness and condensation but do not hold back water that is pushing through during storms.
Match the fix to the source. Water at the joint where the floor meets the wall usually means hydrostatic pressure, and an interior drain fixes it. Water through one crack usually just needs crack injection. Damp walls with no puddles are often condensation, which a dehumidifier solves.
Cheap fixes to try first
A large share of wet basements are caused by roof water dumped next to the foundation. Before paying for a system, try these:
- Clean gutters and make sure they are not overflowing in heavy rain.
- Extend downspouts 6–10 feet from the house. Extensions cost $10–$30 each, buried lines $500–$1,500.
- Regrade soil so it slopes away from the foundation about 6 inches over the first 10 feet.
- Seal window wells and add covers.
- Run a dehumidifier if the problem is dampness rather than water.
What drives the price
- Perimeter length and how many walls need treatment.
- Method. Exterior work costs roughly twice as much as interior.
- Finished basements. Drywall, carpet, and built-ins along the walls must come out, and putting them back is often not in the quote.
- Access outside. Decks, patios, driveways, and AC units raise exterior prices.
- Number of sump pumps and backups.
- Region. Labor in major metros runs 15–30% above the national average.
Frequently asked questions
How much does it cost to waterproof a basement?
Most full basement waterproofing jobs cost $6,000 to $20,000. Sealing a single leaking crack costs $350 to $1,000, and a sealer-only job on a small basement can be under $3,000. Exterior excavation on a large house can pass $40,000.
Is interior or exterior waterproofing better?
Exterior waterproofing stops water before it reaches the wall, so it is the more complete fix, but it costs roughly twice as much and tears up the yard. Interior drain tile does not stop water from entering the wall, it captures it and pumps it out. It is cheaper, works year-round, and is what most contractors recommend for existing homes.
Do waterproofing paints and sealers work?
Only for dampness and light seepage. Sealers cannot hold back water under pressure from saturated soil, so they fail on walls that actually leak during storms.
Does waterproofing add value to a house?
A dry basement with a transferable warranty helps a sale, and a known wet basement hurts it. It also makes it possible to finish the basement, which adds living space.
Can I waterproof a basement myself?
You can clean gutters, extend downspouts, regrade soil, and apply sealer yourself. Interior drain tile means breaking and re-pouring concrete along every wall, which most homeowners leave to a pro.