Long Island Construction Permit Guide 2026: What You Need to Know

If you’re planning a construction project on Long Island, understanding the permit process is one of the most important steps before any work begins. Permits protect you as a homeowner — they ensure that work is done to code, inspected by the town, and won’t create problems when you sell your home.

Here’s a straightforward guide to construction permits on Long Island in 2026, covering what needs a permit, how the process works, and what to expect.

Which Projects Need a Permit?

Most construction work on Long Island requires a building permit. The general rule: if you’re changing the structure, layout, plumbing, or electrical systems of your home, you need a permit.

Projects That Require a Permit

Additions and new construction — any new structure or expansion of an existing one
Kitchen and bathroom remodeling — when moving plumbing, electrical, or walls
Foundation work — new foundations, repairs, and footings
Retaining walls — typically required for walls over 4 feet high
Roofing — full roof replacements (not minor repairs)
Decks and porches — new construction or major modifications
Fences — most towns require permits, especially over 6 feet
Driveways and curb cuts — new driveways or widening existing ones
Electrical work — new circuits, panel upgrades, and rewiring
Plumbing work — new lines, relocating fixtures, and water heater replacements

Projects That Typically Don’t Need a Permit

Minor cosmetic updates (painting, flooring, countertop replacement)
Cabinet refacing without layout changes
Replacing fixtures in the same location (sink for sink, toilet for toilet)
Landscaping and garden work
Small shed structures under a certain square footage (varies by town)

When in doubt, call your local building department. They’ll tell you whether your project needs a permit — and it’s always better to ask before you start.

How the Permit Process Works

The permit process on Long Island follows a similar pattern across most towns, though specific requirements and timelines vary.

Step 1: Application

You or your contractor submits an application to the town building department. The application typically requires:

Property survey
Architectural drawings or plans (for structural work)
Scope of work description
Contractor license information
Proof of insurance
Filing fee

Step 2: Plan Review

The building department reviews your plans for code compliance. This can take anywhere from a few days for simple projects to several weeks for complex construction. Some towns offer expedited review for an additional fee.

Step 3: Permit Issuance

Once approved, the permit is issued and must be posted at the job site. The permit specifies which inspections are required and what work is authorized.

Step 4: Inspections

Inspections happen at key stages of the project — foundation, framing, rough plumbing and electrical, insulation, and final. Your contractor coordinates these inspections with the building department.

Step 5: Certificate of Completion

After the final inspection passes, the town issues a Certificate of Completion (or Certificate of Occupancy for new construction). This document proves the work was done to code and is essential for your records.

Nassau County Building Departments

Nassau County doesn’t have a single county-wide building department — each town and city handles its own permits. Here are the main building departments:

Town of Hempstead — the largest town in Nassau County, covering Baldwin, Bellmore, East Meadow, Freeport, Garden City, Levittown, Merrick, Oceanside, Rockville Centre, Seaford, Valley Stream, Wantagh, and many more communities
Town of North Hempstead — covers Great Neck, Manhasset, Port Washington, Roslyn, New Hyde Park, Williston Park, and Westbury
Town of Oyster Bay — covers Syosset, Massapequa, Hicksville, Bethpage, Farmingdale, Plainview, Woodbury, and Jericho
City of Glen Cove — independent city with its own building department
City of Long Beach — independent city with its own building department

Suffolk County Building Departments

Like Nassau, Suffolk County’s towns each have their own building departments:

Town of Babylon — covers Babylon Village, West Babylon, Lindenhurst, Deer Park, North Babylon, Copiague, West Islip, and Amityville
Town of Brookhaven — the largest town in Suffolk County, covering Patchogue, Port Jefferson, Coram, Centereach, Mastic Beach, Medford, Selden, Shirley, Holbrook, and more
Town of Huntington — covers Huntington Village, Huntington Station, Cold Spring Harbor, Dix Hills, Commack, Greenlawn, and Centerport
Town of Islip — covers Bay Shore, Brentwood, Central Islip, East Islip, Holbrook, Sayville, Ronkonkoma, and Bohemia
Town of Smithtown — covers Smithtown, Nesconset, Kings Park, St. James, Commack, and Hauppauge
Town of Riverhead — covers Riverhead, Calverton, and Wading River
Town of Southampton — covers Hampton Bays, Westhampton, and the villages within
Town of East Hampton — covers East Hampton, Amagansett, Montauk, and Springs

Common Permit Costs on Long Island

Permit fees vary by town and project scope, but here are typical ranges you can expect in 2026:

Project Type	Typical Permit Fee
Kitchen or bathroom remodel	$150 – $500
Deck or porch	$200 – $600
Addition or extension	$500 – $2,000+
New construction	$1,500 – $5,000+
Roofing	$150 – $400
Fence	$50 – $200
Driveway	$100 – $300
Electrical work	$100 – $400
Plumbing work	$100 – $400

Fees are typically based on the estimated cost of construction or the square footage of the project. Some towns also require separate permits for electrical, plumbing, and mechanical work in addition to the building permit.

What Happens If You Skip the Permit?

Working without a required permit creates real problems:

Stop work orders — the town can shut down your project mid-construction
Fines — penalties for unpermitted work, which can be substantial
Difficulty selling — buyers and their attorneys check for open permits and unpermitted work during closing
Insurance issues — damage resulting from unpermitted work may not be covered
Required removal — in some cases, you may be required to remove unpermitted work entirely

We’ve seen homeowners spend thousands correcting unpermitted work done by previous contractors. It’s always cheaper and easier to get the permit upfront.

How JZ Development Handles Permits

As a licensed Long Island general contractor (HI-67427), we handle the full permit process for our clients. That includes preparing applications, submitting plans, scheduling inspections, and ensuring everything passes. Our familiarity with building departments across Nassau and Suffolk County means we know each town’s requirements and can navigate the process efficiently.

If you’re planning a construction project on Long Island and want to make sure it’s done right — permitted, inspected, and built to code — contact us for a free estimate.