How much does it cost to waterproof a basement?
Ashburn, VA

How much does it cost to waterproof a basement?

Ashburn, VA

How much does it cost to waterproof a basement?

$6 – $15per square foot total
$250 – $800per crack for epoxy injection only
$4,500 – $10,000total interior waterproofing (750 – 1,000 SF)
$10,000 – $15,000total exterior waterproofing (750 – 1,000 SF)

Get free estimates for your project or view our cost guide below:

$6 – $15 per square foot total

$250 – $800 per crack for epoxy injection only

$4,500 – $10,000 total interior waterproofing (750 – 1,000 SF)

$10,000 – $15,000 total exterior waterproofing (750 – 1,000 SF)

Get free estimates for your project or view our cost guide below:
Are you a pro? Get new customers
Sarah Noel
Written by
Sarah Noel
Edited by
Tamatha Hazen
Fact-checked by
Kristen Cramer

Basement waterproofing cost

Interior basement waterproofing costs $4,500 to $10,000 on average. Exterior waterproofing a basement costs $10,000 to $15,000. The cost to waterproof a basement is $6 to $15 per square foot. The total cost depends on the basement size, home's age, and waterproofing methods used.

Basement waterproofing cost by size - Chart
Basement waterproofing cost by size - Chart
Basement waterproofing cost
Basement size (square feet) Average cost*
500 $3,000 – $7,500
750 $4,500 – $11,250
1,000 $6,000 – $15,000
1,250 $7,500 – $18,750
1,500 $9,000 – $22,500
2,000 $12,000 – $30,000
2,500 $15,000 – $37,500

*This cost typically includes fixing cracks, sealing the foundation, waterproofing walls, and installing a sump pump or perimeter drain.

Damp-proofing membranes installed around a basement foundation
Damp-proofing membranes installed around a basement foundation
Get free estimates from basement waterproofing companies near you.

Cost to waterproof a basement by method

Interior waterproofing costs $4,500 to $10,000 on average while exterior waterproofing costs $10,000 to $15,000. The total cost depends on the individual methods needed and the condition of the house, foundation, and basement.

Cost to waterproof a basement by method
Waterproofing method Location Average cost
Concrete sealing Interior $1 – $3 per square foot
Waterproof paint Interior $200 – $1,100
Baseboard channels Interior $30 – $150 per linear foot
Interior French drain Interior $4,000 – $17,000
Sump pump Interior $600 – $2,500
Epoxy injection Interior $250 – $800 per crack
Vapor barrier Interior $1,500 – $4,000
Dehumidifier Interior $1,100 – $2,800
Exterior French drain Exterior $30 – $90 per square foot
Weeping tile Exterior $1,500 – $4,000 per side of house
Waterproof membrane Exterior $4 – $7 per square foot
Cement waterproofing Exterior $20 – $22 per square foot
Sodium bentonite Exterior $2 – $5 per square foot
Yard grading Exterior $500 – $3,000

Interior waterproofing

Interior waterproofing costs $4,500 to $10,000 total for an average job. This price includes the combined services of retrofitting a sump pump French drainage system under the concrete floor of the basement, plus cementing over it afterwards.

Common fees on the higher end of this price range include wall sealing, leak repairs, and adding new pipes to divert water further outside.

Concrete sealers

Concrete sealing costs $1 to $3 per square foot on average. The most durable basement sealants form a solid, rubber-like barrier. All types work best when applied to all the joints between the walls and floor. Some types are thinner to allow you to coat all concrete walls and flooring.

Concrete sealing
Sealant type Cost per square foot installed
Acrylic $1 – $2
Silicate $1 – $3
Epoxy $4 – $10
Elastomeric (liquid rubber) $3.50 – $5.75

Waterproof paint

The cost to paint an exterior foundation is $200 to $1,100 on average. Concrete foundations are porous and prone to moisture damage, so sealing and priming are vital for longevity and adhesion. Specialized concrete paint also ensures a smooth finish.

Interior drainage system

An interior French drain costs $4,000 to $17,000 installed on average or $40 to $85 per linear foot. This subfloor drain around the perimeter of the basement uses a gravel-filled trench with a perforated pipe to channel water from walls and beneath the floor to drainage points or sump pumps.

  • Sump pump installation costs $600 to $2,500 on average. While these are often part of a complete drainage system, some people need an additional one.

  • Installing baseboard channels will cost $30 to $150 per linear foot installed. Contractors set the trench drain into the surface of the concrete with a grate over the top. This drain removes all water above or near the floor's surface at the basement floor's perimeter.

Sump pump installed in basement with a water powered backup system
Sump pump installed in basement with a water powered backup system

Epoxy injection

An epoxy injection costs $250 to $800 per crack, depending on the length and depth of the crack. Contractors drill into the concrete and inject the epoxy mixture deep into the cracks to form a complete seal.

Fixing these cracks promptly is important because they can lead to more significant structural issues in the future.

Vapor barrier

Vapor barrier installation costs $1,500 to $4,000 on average or $2 to $4 per square foot. Installing a new vapor barrier will typically include a cleaning and sealing of the entire basement to dry the interior first. Only then can contractors install the vapor barrier. Prices increase for thicker barriers.


The cost to install a dehumidifier in a basement is $1,100 to $2,800. Since moisture will always tend to accumulate in a basement, a dehumidifier is essential to prevent mold spreading through the air. This device also reduces allergens and odors. {#barrier}

Exterior waterproofing

Most exterior waterproofing jobs cost $10,000 to $15,000 total. Typical fees include excavating for a new French drain tile around the foundation, connecting it to a sump pump system, sealing work, and regrading to direct water away from the basement.

Any additional structural repairs to the foundation that are necessary to prevent leaks will cost extra according to the extent of the damage.

A worker applying a bitumen membrane to a foundation's exterior for waterproofing
A worker applying a bitumen membrane to a foundation's exterior for waterproofing

Exterior drainage / weeping tile

An exterior French drain costs $30 to $90 per linear foot installed for a new weeping tile system. These fees include average trenching costs and laying the perforated drainpipes at depths of up to 4' to 5'. Installation depths vary depending on the frost line location in your climate.

Exterior weeping tile installation costs $1,500 to $4,000 per side of house or $10 to $35 per linear foot when installed near the ground's surface in warm climates.

Waterproof membrane

Liquid and sheet waterproofing membranes cost $4 to $7 per square foot installed. Contractors apply liquid membranes like any other sealant coating, whereas rubberized asphalt sheet membranes can be a more durable water barrier since they're thicker. These barriers go on the basement walls and the foundation footing.

Contractors waterproofing the foundation with protective membrane
Contractors waterproofing the foundation with protective membrane

Cement waterproofing

Cementitious waterproofing costs $20 to $22 per square foot for excavation and application on exterior foundation walls underground. Fees are $1.50 to $2.00 per square foot for waterproofing interior walls only. Cement-based foundation coatings make a durable, easy-to-apply finish that patches cracks and sealing basements.

However, its inflexibility can reduce effectiveness with joint movement or cracking.

Sodium bentonite

Bentonite clay waterproofing costs $2 to $5 per square foot. Contractors inject this natural sealant in slurry form in the ground next to exterior walls to seal cracks. Clay absorbs water to create a barrier, but it's a temporary fix. Building codes don't always allow it since clay can block drains.


Yard grading costs $500 to $3,000 on average for fixing the grading around a house depending on if the earthwork is necessary along one wall or around most of the yard. Rough grading costs $1 to $2 per square foot for slope removal or reshaping smaller areas for proper drainage.

Get free estimates from basement waterproofing companies near you.
Waterproofing a basement with bitumen spray on tar
Waterproofing a basement with bitumen spray on tar

Waterproofing a basement cost factors

Common cost factors for waterproofing a basement include:

  • Size & layout – Larger basements or complex layouts can increase waterproofing costs due to the extra materials and labor required.

  • Method – Exterior waterproofing costs more to address water-drainage issues from the outside. Interior waterproofing is cheaper but may not tackle the underlying issues as effectively.

  • Geographic location – High humidity, heavy rainfall, and flood-prone areas have a higher demand for waterproofing that can raise costs.

  • Home age – Homes built before 1960 face higher basement waterproofing costs due to outdated structures and building materials that are more prone to leaks.

  • Foundation conditionBasement foundation repairs cost $500 to $2,000 for fixing minor issues. Major repairs cost up to $25,000 for large cracks, severe leaks, and bowed walls.

  • Repairing brick wallsBrick repair costs $500 to $2,500 on average or $10 to $30 per square foot, depending on the damage and repair method.

  • Mold – Average mold remediation costs $1,500 to $6,000 for cleanup after severe water damage.

  • Excavation – Fees for exterior waterproofing with excavation costs $100 to $300 per hour for an excavator and operator to make trenches for new drains.

  • Finished vs. unfinished basement – Waterproofing a finished basement is more complex and expensive, especially if flooding requires replacing drywall and flooring.

  • Landscape repairs – A landscaper charges $50 to $100 per hour for a 2-person crew performing lawn repairs.

  • Gutters & downspouts – Extending downspouts will lower basement waterproofing costs by directing rainwater runoff away from the foundation.

  • New egress window – A new basement egress window costs $3,000 to $7,000 installed. These window wells sometimes fail, and then they may need replacing to fix basement leaks.

  • Wall reinforcements – Wall anchors cost $400 to $900 each, placed at every 5 feet of the wall's span. Carbon fiber straps cost $3,000 to $5,000 for basement walls up to 20' to 25' in length.

Insulating and waterproofing basement foundation with damp proofing coating and bitumen membrane
Insulating and waterproofing basement foundation with damp proofing coating and bitumen membrane

Basement waterproofing FAQs

What is basement waterproofing?

Basement waterproofing includes installation of sealants, drains, and barriers to stop all water penetration into the home. Professionals will repair all existing basement damages as well. Contractors may also regrade the yard to create a better slope that directs rainwater away from the home.

How do I know if my basement needs waterproofing?

You'll know your basement needs waterproofing if you notice these signs:

  • Standing water or leaks in the basement

  • Dampness or a musty odor

  • Water stains

  • Wet or chalky walls

  • Mold and mildew

  • Bowed walls or warped doors

  • Cracks in the walls or floors

  • Water leaking inside through window wells or egress windows

Is basement waterproofing worth it?

Basement waterproofing is worth it to prevent water damages like mold growth and structural failures in your foundation. Waterproofing a basement can greatly improve your living conditions as well.

What is the cheapest way to waterproof a basement?

The cheapest ways to waterproof a basement are:

  • Adding longer downspout extenders onto your gutters

  • Creating slopes away from your foundation with fill dirt

  • Applying waterproof paint to the basement walls and floor

  • Sealing all cracks and floor joints with epoxy

However, these methods won't waterproof a basement if the building has serious structural damages or there are major drainage issues on the property.

What is the best basement waterproofing method?

The best basement waterproofing method is the one that keeps the most water from entering the basement and pooling around the foundation. Exterior waterproofing with a drainage system is typically the most effective solution but also costs the most.

How long does it take to waterproof a basement?

Waterproofing a basement typically takes 1 to 3 days for a space up to 300 square feet, depending on the accessibility and methods used. External methods that require a lot of digging may take up to a week of work.

Can you waterproof a basement from the inside?

Yes, you can waterproof a basement from the inside with sealants, internal drainage systems, and water barriers. However, exterior waterproofing methods may be necessary to decrease the risks of walls bowing from water pressure buildup in the soil around your foundation.

How long does basement waterproofing last?

Basement waterproofing should last from 10 to 25 years or more with properly installed drainage solutions. Other waterproofing methods like only applying a sealant won't last as long if the cause of the water leaks isn't addressed.

Does basement waterproofing increase my home value?

A waterproofed basement may increase the home's value, especially if you plan on reselling it in less than 5 years. If the required home inspection lists water damages in the basement, then you may need to pay for waterproofing repairs just to sell the home.

Get free estimates from basement waterproofing companies near you.

Does homeowners insurance cover basement waterproofing?

Homeowners insurance typically doesn't cover installation of full waterproofing systems. However, the insurance may cover damage repairs after an appliance breaks, a pipe bursts, or after a natural disaster like a flood. Check your insurance policy to confirm your terms and coverage limits.

Getting estimates from basement waterproofing company

Before hiring a basement waterproofing company near you, be sure to:

  • Request 3+ quotes from licensed, bonded, and insured companies to compare.

  • Check if they have credentials from the Basement Health Association, the EPA, or the National Association of the Remodeling Industry.

  • Ask if they're part of any local building or plumbing associations.

  • Read their past reviews on HomeGuide and Google.

  • Confirm if the contractor has 5+ years of experience.

  • Get an itemized estimate and contract copy before the job starts.

  • Avoid hiring the cheapest contractors who can have low-quality service.

  • Never pay in full until the job is complete.

Questions to ask a basement waterproofing contractor

Ask these essential questions to find a good basement waterproofing company:

  • What's your minimum fee for a basement inspection and assessment?

  • How long have you been in the basement waterproofing business?

  • What experience do you have with waterproofing basements like mine?

  • How is water getting into my basement?

  • Are there structural problems that could cause the walls to fail?

  • Which waterproofing methods do you recommend for my basement and why?

  • Does your estimate cover materials, labor, delivery fees, and cleanup?

  • Will I need to pay extra to repaint my walls or floor afterward?

  • How long will the waterproofing process take?

  • Will we be able to stay in our home during the work?

  • Can you provide references from past clients with similar projects?

  • Will you give me a written estimate, contract, and timeline for the project?

  • What do you do if unexpected problems arise?

  • Can you offer me a guarantee on your work?

  • How should I prepare for your crew, and how many people are coming?