NJ Sump Works Blog · Updated September 2026

How Much Does Basement Waterproofing Cost in NJ?

Short answer: a full interior French drain system with a sump pump runs $5,000–$12,000 in North Jersey. Most homeowners pay $7,000–$9,000. Here's what drives the price — and what each piece costs.

Price ranges for every waterproofing job

• Interior French drain + sump pump (full perimeter): $5,000–$12,000. The most common job we do — and the one that permanently solves seepage and flooding in most NJ basements.
• Partial perimeter drain: $2,500–$6,000. When water only enters along one or two walls, a partial system can be enough.
• Sump pump replacement: $500–$1,200. New pump, check valve, and discharge inspection in an existing pit.
• New sump pump installation (no existing pit): $800–$2,000. Cutting the pit and running discharge adds labor.
• Battery backup sump pump: $600–$1,200 installed. Keeps pumping through power outages.
• Foundation crack injection: $300–$800 per crack. Low-pressure epoxy or polyurethane, done from the inside.
• Basement dehumidifier: $1,200–$2,500 installed. High-capacity units with automatic drainage.
• Mold remediation: $1,500–$6,000+ depending on extent. Small areas are quick; whole-basement jobs take days.
• Exterior excavation waterproofing: $15,000–$30,000+. Rarely needed — we only recommend it when interior drainage genuinely can't solve the problem.

What drives the price up or down

Basement size and perimeter length. A French drain is priced largely by the linear foot, so a sprawling Wayne colonial costs more than a compact Passaic cape. Bigger basements, bigger systems.

Access. A wide-open unfinished basement is fast to work in. A finished basement with walls tight to the perimeter, or a basement packed with storage, adds labor. We plan around finished spaces, but it takes more time.

Foundation type. Poured concrete is straightforward. Old stone foundations — common in Paterson's Hillcrest section — need wall drainage channels and more careful work, which adds cost.

Water volume. A basement that seeps in heavy rain needs a standard system. A basement sitting in a high water table near the Hackensack River may need a larger pump, a deeper pit, or dual pumps — more equipment, more money.

Mold. If years of moisture have grown mold behind walls or on framing, remediation gets added to the job. This is the cost that grows the longer you wait — a damp basement in September is a moldy basement by next spring.

How to save money (without getting burned)

Get multiple quotes, but compare what's actually included — pump quality, basin type, discharge routing, and warranty terms vary enormously. The cheapest bid often means a builder-grade pump with no backup and a one-year warranty. Ask every contractor: what's the pump brand and horsepower, is the basin sealed, where does the discharge go, and what exactly does the warranty cover?

Fix it once, fix it right. The most expensive waterproofing is the kind you pay for twice — a cheap partial fix that fails, then the real system on top of it. And don't wait for the "big one": waterproofing before a flood is always cheaper than waterproofing plus mold remediation plus replacing everything the water ruined.

The bottom line

For most North Jersey homeowners, budget $7,000–$9,000 for a full interior system that permanently solves the problem — drainage, pump, and discharge done right. Smaller fixes run hundreds to low thousands. The only way to know your number is an inspection: ours are free, written, and firm. Call Clifton, Paterson, Passaic, Wayne, or Hackensack — we'll tell you the smallest fix that actually works.

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