Find a licensed basement waterproofing company in Smithtown, NY

Who licenses basement waterproofing companies in Smithtown

• 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.

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

What the Town of Smithtown requires

• The Town requires a building permit to finish a basement.
• The Town's FAQ says state codes allow habitable basement space only when the minimum ceiling height, smoke detector and egress requirements are met.
• An outside basement entrance can be applied for through the Town's online residential permit system.
• Development in a floodplain needs the Town's floodplain development permit before any work starts, and it cannot be used or occupied until a certificate of compliance is issued.
• The Town Planning Director decides whether a project sits in the floodplain, and the permit expires if work does not begin within six months.
• The floodplain permit form asks for the as-built elevation of the top of the lowest floor, basement included.

The Town of Smithtown Building Department handles permits ((631) 360-7520). Our Town of Smithtown permit guide covers how to apply, inspections and certificates.

Homes in Smithtown: what the Census shows

Across the Town of Smithtown, villages included, the median home was built in 1968, and 24% of homes were built before 1960. 89% of homes here are owner-occupied, and 86% 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 Smithtown

• 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 Smithtown 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?