Basement Waterproofing Cost: Interior, Exterior and Drains
Basement waterproofing ranges from a few hundred dollars for sealing a crack to $20,000 or more for digging out and membraning the outside walls. Most wet basements are fixed with an interior drain and sump pump, which is priced by the foot.
Updated November 2026 · 6 min read
These are national price ranges for education only. They are not a quote or a promise of what any company will charge for your home.
Cost by method
National ranges from This Old House’s 2026 cost guide:
| Method | Typical range | Fixes |
|---|---|---|
| Waterproof coating on interior walls | $1 to $8 per sq ft | Dampness and condensation, not active leaks |
| Crack injection | $800 to $1,500 per crack | A single leaking crack |
| Interior perimeter drain | $60 to $120 per linear ft | Water at the wall-floor joint, groundwater |
| Sump pump installation | $1,200 to $2,500 | Pumping out water the drain collects |
| Exterior waterproofing | $7,000 to $15,000 | Water through the walls, from outside |
| Full excavation with drains and membrane | $20,000 or more | Severe or repeated leaks on all sides |
What a typical interior system costs
An interior drain is cut into the floor along the walls that leak, so the length of wall drives the price. A basement with water along one 40-foot wall needs far less than one leaking on all four sides. At $60 to $120 per foot, 40 feet of drain runs about $2,400 to $4,800 before the pump; a full perimeter of 140 feet runs about $8,400 to $16,800.
French drain cost
An exterior French drain, a gravel trench with a perforated pipe that carries water away from the house, ranges widely, from about $10 to $100 per linear foot, depending on depth, soil and whether it ties into the footing. Shallow yard drains sit at the low end; drains dug down to the footing sit at the top.
Cheap fixes to try first
| Fix | Typical cost |
|---|---|
| Downspout extensions | A few dollars each, DIY |
| Regrading soil away from the walls | Low if DIY; more with a landscaper |
| Window well covers | Low, DIY |
| New gutters | $650 to $1,750 installed |
Much of the water that ends up in basements comes off the roof. In Murfreesboro’s clay soil, which drains slowly, getting roof water well away from the house can make a bigger difference than any coating on the inside.
What raises the cost
- Finished walls and floors that have to come out to reach the problem
- Water coming in on several walls instead of one
- Bowing or cracked walls that need structural repair first
- Mold or water damage cleanup from past leaks
- A battery backup pump, which adds to the sump cost but covers power outages
Is waterproofing a basement worth it?
If the basement takes on water regularly, yes. Repeated water ruins finishes and stored belongings, grows mold, and shows up on inspection when you sell. If it was damp once in a record storm, start with gutters and grading before paying for a system.
When it needs a professional
Gutters, downspouts and grading are homeowner jobs. Water through the floor joint or walls after every heavy rain needs a drainage system. See how basement waterproofing is done, or start with why water gets in after rain.
Basement waterproofing cost questions
How much does it cost to waterproof a 1,000 sq ft basement?
It depends on how much wall leaks, not the floor area. Sealing and gutter fixes can be under $2,000; full waterproofing of a 1,000 sq ft basement averages about $13,600 nationally.
How much does it cost to waterproof a 500 sq ft basement?
Smaller basements have less wall, so an interior drain and pump often lands in the mid four figures. A single leaking crack can be under $1,500.
Is interior or exterior waterproofing better?
Exterior stops water before it reaches the wall but costs much more and tears up the yard. Interior drains manage water that gets in and are the common choice for existing homes.
Does sealing paint stop basement leaks?
Not active leaks. Coatings help with dampness and condensation, but water under pressure pushes them off the wall.