Basement Waterproofing Cost Calculator
Basement Waterproofing costs $4,650 to $7,050 for a typical 60 linear feet job in 2026, against a national benchmark of $5,675. Labor runs 44 crew hours at $40.06 an hour. Enter a ZIP code to apply that area's measured wages for this work and its regional price level.
What makes up the price
Cost by size
National averages, before any local adjustment. Computed from the same model as the calculator above, so the two always agree.
| Wall being treated | Linear feet of wall | Typical | Range |
|---|---|---|---|
| 30 linear feet | 30 | $3,825 | $3,150 to $4,750 |
| 50 linear feet | 50 | $5,075 | $4,150 to $6,275 |
| 60 linear feet | 60 | $5,675 | $4,650 to $7,050 |
| 80 linear feet | 80 | $6,925 | $5,675 to $8,575 |
| 100 linear feet | 100 | $8,150 | $6,675 to $10,100 |
Three jobs, one name
A contractor saying "basement waterproofing" could mean any of these, and they are not grades of the same product:
| Method | 60 feet of wall | Per foot | What it does |
|---|---|---|---|
| Interior coating | $2,275 | $38 | Seals a damp wall from the inside |
| Interior drain and sump | $5,675 | $95 | Gives water that reaches the wall a way out |
| Exterior excavation | $8,225 | $137 | Keeps water out of the wall in the first place |
The spread is more than three to one, and the cheapest one is the one most often sold to somebody who needed a different one. A coating applied to a wall under real water pressure will fail, usually within a season or two, and it will take the paint and some of the masonry surface with it when it goes.
Work out which one you need first
The symptom tells you the method. In rough order:
- Musty smell, walls feel cool and damp, no visible water. That is vapor moving through masonry. A coating handles it, and so does a dehumidifier running on a drain line. Start at the cheap end.
- Damp patches that come and go with the weather, efflorescence — the white powdery bloom on block or concrete. Water is moving through the wall. A coating may buy a few years; it is not the fix.
- Water running in at the joint between the floor and the wall after a storm. This is the common one, and it is what an interior drain is for. Water is arriving at the footing under pressure and a coating cannot hold it back.
- Water through a visible crack in a poured wall. That is a crack repair, not a waterproofing job — injection is a few hundred dollars per crack. See wall crack repair.
- Standing water, or water coming up through the floor. The water table is above the slab, at least some of the time. An interior drain and a sump, and the pump is not optional.
Do the free things before you pay for any of this
Half the quotes written for wet basements are for problems the roof is causing:
- Extend every downspout at least six feet from the wall. A thousand square feet of roof in a one-inch rainfall sheds about 600 gallons. A downspout ending in a splash block puts all of it into the soil beside the footing.
- Check the grade. The ground should fall about six inches in the first ten feet away from the house. Settled backfill that slopes back toward the wall is the second most common cause.
- Clear the gutters. A blocked gutter is a downspout that discharges at the wall along its whole length.
If the basement stays dry through a heavy storm after that, nothing on this page is needed. If it does not, you have a groundwater problem and the rest of this is the real conversation. A yard drain intercepting water before it reaches the house can also be part of the answer — see french drain installation.
Measure the wet walls, not the perimeter
This is the single biggest number on the page and almost nobody questions it. Water comes in on the uphill side, which is usually one or two walls out of four. A 1,200 square foot basement has roughly 140 feet of wall; treating the two walls that are actually wet is 60 feet.
- 60 feet of interior drain and sump: $5,675
- 140 feet of the same work: $10,600
Before anyone quotes, mark the floor where it gets wet after a storm. A contractor who measures the full perimeter by default is selling a product rather than fixing a problem, and a system that stops where the water stops works exactly as well.
Inside or outside
Exterior is better engineering. Keeping water out of the wall beats pumping it off the floor, the wall gets a membrane and can be insulated while it is open, and there is no pump to fail. It is also $137 a foot against $95, and that figure does not include putting the yard back — the patio, the plantings, the walk, the deck that had to come off. Once restoration is in, exterior work frequently lands at twice the interior price.
Interior is what most reputable companies sell, and the honest case for it is practical rather than technical:
- It can be done where the outside cannot be reached — a zero lot line, a driveway, a deck, mature trees against the wall.
- It is one or two days instead of a week, with no machine in the yard.
- It can be done one wall at a time as money allows.
What interior work does not do is keep the wall itself dry. On a concrete block wall that matters, because block is hollow and water sits in the cores. An interior drain on block should include weep holes drilled into the bottom course so the wall can drain into the system; without them the wall stays full and the interior face keeps spalling. Ask about this specifically — it is a small amount of extra drilling and it is frequently left out.
The pump is part of the system
An interior drain ends at a sump, and from that point the basement is exactly as reliable as the pump. The figures here include a cast iron pump, a pit and a discharge line. They do not include a battery backup, which is $150 to $500 more and which exists because the power goes out during the storm that causes the flooding. See sump pump installation for what fails and how often.
Where the discharge goes matters as much as the pump. It has to end far enough from the house that the water does not come straight back, it must not run into the sanitary sewer — illegal in most places, and found at the point of sale — and on a line that freezes in February, the pump runs against a closed pipe until it burns out.
Read the warranty before the price
Waterproofing is sold on lifetime transferable warranties, and they are worth having, but they rarely say what readers assume:
- Most cover water on the floor from the system that was installed, not a dry basement. Seepage through a wall above the drain, through a crack, or at a window well is not usually covered.
- Many are void if the pump is not maintained, or if a backup was declined, or if the discharge is altered.
- A warranty is only as good as the company. Basement waterproofing has high turnover, and a lifetime warranty from a firm that closes is a piece of paper.
- Transferable matters at resale, and so does the paperwork. Keep the contract and the invoice with the house documents.
Things sold as waterproofing that are not
- A dehumidifier. Genuinely useful for humidity and mold, and it does nothing about water entering the basement.
- Interior paint or coating over an actively leaking wall. It will fail, and it makes the next contractor's job harder because the new work has to be bonded to sound masonry.
- Encapsulation. That is a crawl space job and a vapor problem — see crawl space encapsulation. It is not drainage.
- Flood vents or a floor drain into nothing. A drain with no outlet is a hole.
What to ask before signing
- Which of the three methods is this, and what symptom made you choose it?
- How many feet of wall, and which walls?
- Is the slab being cut, and who patches it — and how wide will the patch be?
- On a block wall, are weep holes being drilled into the bottom course?
- Where does the discharge end, and is that legal here?
- What is the warranty, what voids it, and is it transferable?
- What is not included — landscaping, framing, drywall, flooring?
Common questions
How much does basement waterproofing cost?
About $5,675 for an interior drain and sump along 60 feet of basement wall, which is $95 a linear foot and the most common job. An interior coating on the same wall is $2,275, or $38 a foot, and exterior excavation with a membrane is $8,225, or $137 a foot. Treating a full 140 foot perimeter with an interior system is $10,600.
Which method does my basement need?
The symptom decides it. A musty smell and walls that feel damp with no visible water is vapor, and a coating handles it. Damp patches that come and go, or white efflorescence on the block, means water is moving through the wall and a coating will only buy a few years. Water running in at the joint between the floor and the wall after a storm is the common case and it is what an interior drain is for. Standing water or water coming up through the slab means the water table is above the floor, and that needs a drain and a pump. Water through a single crack in a poured wall is a crack repair, not a waterproofing job.
Is interior or exterior waterproofing better?
Exterior is better engineering — it keeps water out of the wall rather than pumping it off the floor, the wall can be waterproofed and insulated while it is open, and there is no pump to fail. Interior is what most companies sell, because it costs $95 a foot against $137, it works where the outside cannot be reached, it takes days rather than a week, and the exterior figure excludes putting the yard back. Once landscaping, a patio or a deck has to be restored, exterior work often ends up at twice the price.
Do I have to waterproof the whole perimeter?
No, and this is the biggest saving available. Water comes in on the uphill side, usually one or two walls out of four. A 1,200 square foot basement has about 140 feet of wall, and treating the two walls that are actually wet is 60 feet — $5,675 instead of $10,600 for an interior system. Mark the floor where it gets wet after a storm before anybody quotes. A contractor who measures the full perimeter by default is quoting a product, not a repair.
Does a waterproof coating on the inside walls work?
For dampness, yes — a cementitious coating on sound masonry handles vapor and a musty smell for five to ten years, at about $38 a linear foot of wall. Against water under pressure it fails, usually within a season or two, and it takes some of the masonry surface with it when it lets go. Most of the price is preparation rather than material: the wall has to be ground back to sound masonry, weeps plugged with hydraulic cement and a rough wall parged flat before two coats go on. Applied over a wall that is already wet, it traps the water and pops off.
Why does a concrete block wall cost more to waterproof?
Because block is hollow, so water is inside the wall as well as against it, and the price here is about 8% higher for that reason. It also changes the specification: an interior drain on a block wall should include weep holes drilled into the bottom course so the cores can drain into the system. Without them the wall stays full of water and the interior face keeps spalling however good the drain is. It is a small amount of extra drilling and it is frequently left out of a quote, so ask about it by name.
Is a sump pump included in basement waterproofing?
In an interior drain system it has to be, because a drain with nowhere to send the water is a trench. The figures here include a cast iron pump, a pit and a discharge line. They do not include a battery backup, which is $150 to $500 more and which exists because the power goes out during the storm that causes the flooding. Where the discharge ends matters as much as the pump: too close to the house and the same water comes back, into the sanitary sewer is illegal in most places, and a line that freezes leaves the pump running against a closed pipe.
What does a lifetime waterproofing warranty actually cover?
Usually water on the floor from the system that was installed, not a dry basement. Seepage through the wall above the drain, through a crack, or at a window well is generally excluded. Many warranties are void if the pump is not maintained, if a backup was declined, or if the discharge is altered. Transferability is worth having at resale, and so is keeping the contract and invoice with the house papers. The limit on all of it is the company: this trade has high turnover and a lifetime warranty from a firm that has closed is a piece of paper.
Should I fix the gutters and grading first?
Yes, and it settles a good share of wet basements for nothing. Extend every downspout at least six feet from the wall — a thousand square feet of roof in a one-inch rainfall sheds about 600 gallons, and a splash block puts all of it in the soil beside the footing. Check that the ground falls roughly six inches in the first ten feet away from the house, and clear the gutters. If the basement stays dry through a heavy storm after that, you have no groundwater problem and nothing on this page is needed.
Will a dehumidifier stop a wet basement?
No. A dehumidifier is genuinely useful for humidity, musty smells and mold risk, and it does nothing about water entering the basement — it removes moisture from the air after the water is already inside. The same applies to encapsulation, which is a crawl space vapor job rather than drainage, and to painting a leaking wall. If water arrives at the floor after a storm, the answer is a path out for it or a barrier outside the wall.
Where these numbers come from
Nothing here is copied from a contractor directory. Labor is priced from what the trades are actually paid, materials from published producer prices, and both are adjusted to your area using federal cost-of-living data.
- All other specialty trade contractors, United States: $40.06/hour, August 2026 (BLS CES CES2023899003)
- Pipe, stone, wall board and slab patch: $12.00 per linear foot (price recorded October 2026, not index-adjusted)
- Submersible pump, check valve and fittings: $250.00 per pump (price recorded October 2026, not index-adjusted)
- Pit liner, gravel, slab patch and discharge: $420.00 per pump (price recorded October 2026, not index-adjusted)