Basement · waterproofing cost
Basement waterproofing cost calculator
Price the main waterproofing methods by the linear foot of affected wall — and see where a sump pump or dehumidifier fits in. An independent baseline for comparing contractor quotes.
Estimate only — the right fix depends on where the water comes from. Have a contractor diagnose the source first.
The four common methods
Wet basements get fixed in one of a few ways, and the price gap between them is large:
Find the water source first
The single most expensive mistake is treating the symptom and not the cause. Surface water pooling against the house is often fixed cheaply with grading and gutters; hydrostatic pressure from a high water table usually needs interior drainage and a sump. A contractor (or a structural engineer if there's also cracking) should confirm where the water comes from before you commit to a method.
Frequently asked questions
How much does it cost to waterproof a basement?
It depends heavily on the method. Interior drain tile with a sump pump commonly runs $40–$100 per linear foot of wall plus $600–$2,000 for the pump. A full exterior excavation and membrane is the most thorough and most expensive at roughly $80–$200 per linear foot. Light interior sealant is the cheapest but only handles minor dampness.
Interior drain tile vs. exterior membrane — which do I need?
Interior drain tile manages water that has already reached the wall and routes it to a sump — reliable and less disruptive. Exterior membrane stops water before it touches the wall but requires excavating around the foundation. Persistent hydrostatic pressure usually points to interior drainage; recurring exterior wall leaks may justify the dig.
Does a sump pump come with waterproofing?
An interior drain-tile system is built around a sump pump and basin, so we include it by default. Other methods may not need one. A battery backup pump is a smart add-on in flood-prone areas.
Is basement water damage covered by insurance?
Gradual seepage and hydrostatic pressure are excluded as maintenance — you pay for waterproofing out of pocket. A sudden burst pipe is different and may be covered. Check the cause with our insurance verdict tool.
Sources & methodology
- Waterproofing & repair cost data — HomeGuide
- Foundation repair cost data — Angi (national average ≈ $5,000; range ≈ $2,200–$8,100)
- Foundation & basement repair cost guides — This Old House
- A licensed structural engineer / foundation contractor in your area — the authoritative source for diagnosis, scope, and a stamped repair plan
Estimates compiled from the sources above and standard cost models — not engineering, professional, insurance, or legal advice, and may not reflect your policy or local prices. See our full methodology and disclaimer.