How much does basement waterproofing cost in Long Island, NY?

Most Long Island homeowners spend between $3,900 – $15,600 on basement waterproofing, with an average around $8,450. Local labor prices 30% above the national average, so Long Island quotes tend to land at the higher end of national ranges.

Why is basement waterproofing more or less expensive in Long Island than elsewhere?

Nassau and Suffolk crews are busy year round with premium suburban pricing. Coastal wind zones and nor easters affect roofing and siding.

Do I need a permit for basement waterproofing in Long Island, New York?

Town-level permits vary widely and can be slow. Always confirm current requirements with the local building department before signing a contract, and make sure the permit is pulled by your licensed contractor.

How many quotes should I get in Long Island?

Get at least three written quotes from licensed, insured New York contractors. Comparing line items — not just the bottom line — is the fastest way to spot an inflated bid in the New York City market.

How much does basement waterproofing cost?

$3,000 to $12,000 on average. Interior drainage is $3,000 to $10,000; exterior excavation is $8,000 to $25,000.

Interior or exterior waterproofing?

Interior drain tile manages water that gets in and costs far less. Exterior membrane keeps water out entirely and is the permanent fix, at two to three times the price.

How much is a sump pump?

$1,000 to $3,000 installed, plus $500 to $1,500 for a battery backup that keeps working during a storm outage.

Is waterproofing covered by insurance?

Groundwater seepage is excluded from standard homeowners policies. Separate flood insurance or a water backup endorsement is required.

Will waterproofing fix mold?

It stops the moisture source, but existing mold needs separate remediation, typically $1,500 to $6,000.

Does a dry basement add value?

Yes — a documented, warrantied waterproofing system removes a major buyer objection and enables finishing the space.

Home/Cost guides/Basement Waterproofing/Long Island, NY

New York City · New York

Basement Waterproofing cost in Long Island, NY

Long Island homeowners typically pay $3,900 – $15,600 for basement waterproofing. Local labor and materials price 30% above the national average.

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Long Island average

$8,450

Typical low

$3,900

Typical high

$15,600

Per linear foot

$52 – $325

Sample ZIP

11530

What drives Long Island pricing

Local labor

Nassau and Suffolk crews are busy year round with premium suburban pricing.

Permits & code

Town-level permits vary widely and can be slow.

Climate & conditions

Coastal wind zones and nor easters affect roofing and siding.

Instant cost calculator

Adjust the inputs to see live pricing

Wall length to treat80 linear feet

Method

Foundation depth

Exterior access

Water problem

Estimated project cost

$520 – $1,600

Most homeowners pay around $1,060

Compare method

Cost by material in Long Island

Installed Long Island pricing per linear foot.

Option	Installed cost	Pros	Cons
Interior sealant	$7 – $20	Cheapest, DIY possible	Cosmetic — does not stop hydrostatic pressure
Interior drain tile + sump	$52 – $130	Effective, no landscaping destroyed, done in days	Relies on a pump and power
Exterior membrane	$130 – $325	Stops water before it reaches the wall — the permanent fix	Most expensive and disruptive
Crawlspace encapsulation	$26 – $78	Controls humidity, mold and energy loss	Needs a dehumidifier to keep working
Wall reinforcement	$105 – $260	Addresses bowing plus water together	Structural scope and engineering

Where the money goes in Long Island

A typical $8,450 Long Island project, broken down by line item.

Labor and excavation50% · $4,225
Drainage materials22% · $1,859
Sump pump and equipment16% · $1,352
Concrete restoration and disposal12% · $1,014

Common add-ons

Extras that show up on Long Island quotes but rarely in the headline price.

Sump pump

$780 – $2,600

Battery backup

$650 – $1,950

Dehumidifier

$1,550 – $3,900

Mold remediation

$1,950 – $7,800

Vapor barrier

Per square foot

$3 – $8

Egress window

$3,250 – $7,800

Ways to save in Long Island

Do the cheap exterior fixes first — gutters, downspout extensions and grading solve many wet basements for under $1,000.
Choose interior drain tile over exterior excavation unless the wall itself is failing.
Get bids from waterproofing specialists and a general contractor; approaches and prices differ enormously.
Ask about a transferable lifetime warranty — it holds value at resale.
Install the sump and drainage before finishing the basement, never after.

Long Island FAQs

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More Long Island research

Best basement waterproofing companies in Long Island Basement Waterproofing permits in New York Basement Waterproofing near me All New York prices

Basement Waterproofing cost near Long Island

Basement Waterproofing cost in New York, NY

$4,260 – $17,040

Basement Waterproofing cost in Brooklyn, NY

$4,140 – $16,560

Basement Waterproofing cost in Queens, NY

$3,990 – $15,960

Basement Waterproofing cost in Bronx, NY

$3,930 – $15,720

Basement Waterproofing cost in Staten Island, NY

$3,900 – $15,600

Basement Waterproofing cost in Yonkers, NY

$3,870 – $15,480

More New York cities

Buffalo Rochester Albany Manhattan Syracuse White Plains

Other project costs in Long Island

Fence Installation in Long Island

$1,950 – $5,200

Roof Replacement in Long Island

$11,050 – $44,200

Kitchen Remodel in Long Island

$23,400 – $123,500

HVAC Replacement in Long Island

$7,150 – $23,400

Deck Building in Long Island

$5,720 – $15,600

Window Replacement in Long Island

$585 – $1,950

See every Long Island cost guide