Find a licensed basement waterproofing company in Shelter Island, NY

Who licenses basement waterproofing companies in Shelter Island

• Waterproofing is named in Suffolk County's home improvement law, and the law makes a county license mandatory for the businesses it regulates, unless exempt.
• Basements and waterproofing both appear on Suffolk Consumer Affairs' list of home improvement work.
• Work in the electrical and plumbing fields is excluded from Suffolk's home improvement definition.
• A waterproofing contractor working without a license in Suffolk is subject to arrest and prosecution, Consumer Affairs warns.
• Shelter Island requires home improvements to be performed by a licensed contractor holding a Shelter Island license.
• Shelter Island's notice to contractors says every contractor or subcontractor working on the island, landscapers included, needs a town license.
• Shelter Island takes home improvement license applications online, and a new license needs a $250 check to the town, a liability certificate naming the town as certificate holder and, if applicable, a workers' compensation certificate.

State rules and the lookup steps: how to check a basement waterproofing company's license.

What the Town of Shelter Island requires

• Shelter Island requires a topographical survey showing flood zone boundaries for all new construction and for waterfront or low-lying properties.
• All new construction on Shelter Island must be designed to keep water runoff on the property.
• Shelter Island's homeowners handbook says a repair may need a building permit, and an expansion or reconstruction will certainly need one.
• Rebuilding an existing structure in place and in kind on Shelter Island still needs a permit, and the rebuilt structure must meet setbacks.

The Town of Shelter Island Building Department handles permits (631-749-0772). Our Town of Shelter Island permit guide covers how to apply, inspections and certificates.

Homes in Shelter Island: what the Census shows

Across the Town of Shelter Island, villages included, the median home was built in 1980, and 28% of homes were built before 1960, 23% before 1940. 95% of homes here are owner-occupied, and 96% are single-family detached houses.

What basement waterproofing costs here

Labor is a large part of any price. Long Island construction laborers earn a median $58,875 a year, from about $39,468 at entry level to $79,154 with experience. Cement masons and concrete finishers earn a median $65,026 a year, from about $53,234 at entry level to $82,344 with experience. (New York State Department of Labor, wages updated to the first quarter of 2026.) Prices come from written estimates; more in the basement waterproofing cost guide.

Before you hire in Shelter Island

• Ask for the license number the work needs here (see who licenses basement waterproofing companies above), and check it before you sign.
• Ask who files with the Town of Shelter Island Building Department, and who books the inspections.
• Where is the water coming from, in writing, before you sell me a system?
• Would grading, gutters or downspout extensions fix it for less?