Building Permits in NYC and on Long Island: What Needs a Permit and How It Works

Permits can seem like red tape, but they protect you. Permitted work is reviewed and inspected, it is recorded on the property, and it avoids problems when you sell, refinance, or file an insurance claim. Here is how permits generally work in New York City and on Long Island.

Who issues permits

• New York City: The Department of Buildings (DOB) issues construction permits for all five boroughs. Most applications are filed through the online DOB NOW system. Other city agencies have their own permits for related work: DOT for sidewalk and street work, DEP for water and sewer connections and asbestos, FDNY for certain fire protection systems, and the Landmarks Preservation Commission (LPC) for work on landmarked buildings and in historic districts.
• Long Island: Nassau and Suffolk do not have a single building department. Permits are issued by the town (for example Hempstead, North Hempstead, Oyster Bay, Babylon, Huntington, Islip, Brookhaven, Smithtown, Riverhead, Southampton, East Hampton, Southold, Shelter Island) or by an incorporated village if the property is inside one, such as Valley Stream, Garden City, Freeport, or Patchogue. Each sets its own forms, fees, and procedures under the New York State Uniform Code and local zoning.

What typically needs a permit

Requirements vary, but permits are commonly needed for:

• Additions, new construction, and structural changes such as removing load-bearing walls.
• Plumbing and gas work beyond simple fixture replacement.
• New or replaced boilers, furnaces, and water heaters in many jurisdictions.
• Decks, porches, garages, sheds over certain sizes, fences, and pools.
• Changes to exits, stairs, or the building's use or occupancy.
• Demolition.
• Some window, siding, and roofing work, especially on Long Island and in NYC landmark areas.

Cosmetic work such as painting, flooring, and like-for-like cabinet replacement generally does not need a permit, but always confirm for your property.

How the NYC process generally works

1. Plans and filing. For most work, a registered design professional (architect or engineer) prepares plans. Licensed trades file their own work types, such as plumbing filed by a Licensed Master Plumber.
2. Asbestos. DOB requires an asbestos assessment or exemption before issuing permits for most work that disturbs building materials.
3. Plan review and approval.
4. Permit issuance. The contractor pulls the permit, which requires proper licensing and insurance.
5. Inspections during and after the work.
6. Sign-off. The job is signed off, and if needed, the Certificate of Occupancy is amended.

Smaller plumbing jobs may qualify for a Limited Alteration Application (LAA). Emergency plumbing and gas repairs can start under an Emergency Work Notification, followed by a filing.

Co-ops and condos add another layer: board approval, alteration agreements, and insurance requirements.

How the Long Island process generally works

1. Check zoning. Setbacks, height, lot coverage, and use rules apply. If a project does not comply, a variance from the Zoning Board of Appeals may be needed.
2. Prepare plans. Many towns require stamped drawings and a recent property survey for additions and structural work.
3. Submit the application to the town or village building department.
4. Review, which can involve several departments.
5. Permit issuance and posting on site.
6. Inspections at stages such as footing, framing, plumbing, insulation, and final.
7. Certificate of Occupancy or Certificate of Completion at the end.

Plumbing in many Long Island municipalities must be performed by a licensed plumber registered with the town or county.

Legalizing past work

If work was done without permits, you may be able to legalize it by filing plans showing the existing conditions, opening walls for inspection if required, and making corrections. In NYC, unpermitted work often surfaces as a violation; see our guide to clearing building violations.

Tips for a smoother permit process

• Start early. Plan review and approvals take time, and timelines vary by jurisdiction.
• Hire professionals who know the local department.
• Keep copies of approved plans on site.
• Schedule inspections promptly, and do not close walls before required inspections.
• Make sure permits are closed out and signed off when the job is done.

Whether your project is in Brooklyn, the Bronx, Manhattan, Queens, Staten Island, or a town or village in Nassau or Suffolk, understanding the permit path up front keeps the project on schedule.

This article is general information for property owners, not legal or engineering advice. Rules and procedures change; confirm current requirements with the agency or utility involved.