Smithtown is a Suffolk County town of about 117,000 residents on the north shore of Long Island. Its Building Department, at 23 Redwood Lane behind Town Hall, issues permits for the unincorporated town, alongside the incorporated villages inside it that run their own departments.
This guide covers the Building Department, the Suffolk County licence, the village trap, and the codes in force.
This guide covers the Town of Smithtown. The incorporated villages inside the town, such as the Village of the Branch and Head of the Harbor, are separate authorities with their own building departments.
Incorporated villages inside Smithtown file separately, and Suffolk County licenses home improvement contractors. A parcel inside a village such as the Village of the Branch files with the village, not the town. Home improvement contractors need a Suffolk County licence, and harbour and river parcels along the Nissequogue carry drainage and coastal conditions under local law.
What requires a building permit in Smithtown?
Permit required
- New commercial, multi-family and residential construction, additions and change of occupancy
- Structural alterations, load-bearing changes, foundations, decks and retaining walls
- Electrical work — services, panels, circuits, solar and EV charging — under the Uniform Code and the referenced National Electrical Code
- Plumbing under the Plumbing Code of New York State, by a licensed plumber where the jurisdiction requires one
- Mechanical and HVAC change-outs, and work affecting the Energy Code envelope
- Re-roofing above the exempt scope, pools, signs, and demolition
Often exempt
- Minor repairs and maintenance replacing materials in kind
- One-storey detached sheds and playhouses of 144 square feet or less at a one- or two-family home, where the local law exempts them and zoning allows
- Painting, flooring, cabinetry and other finish work
- Like-for-like fixture or appliance swaps with no alteration to wiring or piping
Local amendments and thresholds differ from one jurisdiction to the next, so an exempt list from a neighbouring city is not reliable — a project waved through in one place needs a full permit set in the next. An exemption from a building permit is never an exemption from zoning, the statewide energy code, or any electrical or plumbing permit the municipality requires. Confirm scope with the Building Department before work starts.
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Get a free quote →The statewide layers that apply everywhere
Several layers apply on top of the base building code and routinely catch projects owners assume are exempt: the 2025 Energy Conservation Construction Code of New York State, which took effect alongside the Uniform Code (its all-electric requirements for new buildings remain suspended by court order, according to the Department of State); the truss-construction identification requirements carried in Executive Law; and, in shoreline and flood-prone areas, floodplain administration under the local flood damage prevention law. Snow and ice loading is a live structural constraint across most of the state. Locally, the Town of Smithtown enforces the Uniform Code through its Building Department, with amendments adopted by local law.
New York builds on one statewide code, the Uniform Code, outside New York City; the 2025 edition and 2025 Energy Code took effect on 31 December 2025 (the all-electric provisions remain suspended by court order). Cities, towns and villages administer it, and local standards stricter than the code need Code Council approval. The Uniform Code in New York
Who handles permitting in Smithtown?
The Building Department issues permits and inspects residential and commercial work in the unincorporated Town of Smithtown, outside the incorporated villages.
| Detail | Information |
|---|---|
| Authority | Town of Smithtown Building Department |
| Serves | Unincorporated Town of Smithtown, outside the villages |
| Phone | 631-360-7520 |
| Counter | 23 Redwood Lane (behind Town Hall, 99 West Main Street), Smithtown, NY 11787; Mon–Fri 9:00am–4:00pm |
| Code | 2025 Uniform Code with local amendments |
| Filing | Online for listed residential projects (CitySquared portal); other work at the department counter |
| Licensing | Suffolk County Home Improvement licence; master plumber |
| Records | Permit records held by the department |
Home improvement contractors need a Suffolk County Home Improvement licence from the county Department of Labor, Licensing and Consumer Affairs; there is no statewide contractor licence. Plumbing work files under a licensed master plumber.
North-shore and river parcels along the Nissequogue can carry drainage, wetland and coastal conditions reviewed alongside the building permit.
In 2025, building permits issued in Town of Smithtown authorized 32 new privately owned housing units, all of them single-family homes, according to the U.S. Census Bureau Building Permits Survey.
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Residential permits
Residential work in the unincorporated town is permitted and inspected under the Uniform Code and the town’s local law. River and harbour parcels can carry drainage, wetland and coastal conditions. Minor in-kind repairs and finish work are generally exempt from a building permit but not from zoning.
Commercial permits
Commercial work goes through department plan review against the Uniform Code, the Energy Code and the fire code, with stamped drawings. Waterfront commercial work carries coastal and, where applicable, wetland review.
Licenses, trade classifications and design professionals
Practically, three credential layers appear on New York projects: the local home improvement or contractor registration where the jurisdiction issues one; separately licensed electrical and plumbing trades, licensed locally rather than statewide; and, on commercial and larger residential work, drawings stamped by a New York-licensed architect or professional engineer. Confirm what the Building Department requires for the specific building before filing.
New York has no state general contractor, home-improvement, electrician or plumber licence; licensing is local (New York City and Nassau, Suffolk, Westchester, Putnam and Rockland counties license home-improvement contractors), and the state sets home-improvement contract rules. Contractor licensing in New York
Smithtown permit costs and fees
Budget the town building permit and plan-review fees, separate trade permits, and any drainage or coastal submission fees on waterfront parcels. The Suffolk County licence and worker coverage sit alongside the permit.
| Fee component | How it works |
|---|---|
| Building permit | Based on project valuation or square footage; set by the local schedule |
| Plan check | A percentage of the permit fee or a flat charge, at submittal |
| Trade permits | Separate electrical, plumbing and mechanical fees |
| State surcharges | None: New York has no state permit surcharge, and fees are set locally |
| Impact and school fees | Money in lieu of parkland on some subdivisions and site plans, where the local planning board requires it |
| Re-inspections and revisions | Additional fees for failed inspections, revisions and expired permits |
Rather talk it over?
Call 1-855-478-4290 →New York does not layer a uniform statewide permit surcharge on local charges the way some states do, so the fee is substantially local: each city, town and village sets its own schedule by local law, and neighbouring municipalities on the same road can price the same job differently. A figure from a neighbouring town is not reliable — ask the Building Department for the schedule in force on your filing date.
Need a real number for a specific Smithtown project? Send us the scope, address and valuation and we will identify the authority having jurisdiction, the code edition in force and the fee categories that will apply.
Trade permits and who may pull them
Permit required
- Service installations, panel upgrades, new circuits, solar PV and EV chargers
- New plumbing, repipes, water heater change-outs, fixtures, backflow and gas piping
- HVAC installation and change-out, ductwork, venting and commercial kitchen exhaust
- Sprinkler, standpipe and fire alarm work on commercial and multi-family structures
Typically exempt
- Replacing a fixture, switch, receptacle or light with no alteration to wiring or piping
- Clearing a stoppage without replacing or rearranging concealed piping
- Filter, thermostat and routine component service
- Like-for-like appliance repair that does not alter the connection
Where a municipality issues separate trade permits, the work is done under whatever electrical or plumbing licence that city, town or county requires; many places license neither trade. Trade licences in New York
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Get a free quote →How to apply for a Smithtown building permit
A parcel inside an incorporated village files with the village.
Home improvement contractors register with the county Department of Labor, Licensing and Consumer Affairs.
River and harbour parcels carry drainage and coastal review.
Commercial and larger residential work needs an architect or engineer seal.
Drawings, trade permits and coastal submissions as they apply.
The department inspects to plan and reviews drainage work.
Review, corrections and what actually causes delay
In New York, the first cause of delay is uncertainty over jurisdiction — filing with a town when an incorporated village inside it holds the authority, or assuming a county issues permits when it generally does not. After that come Energy Code documentation, a contractor registration that the jurisdiction does not recognise, and, in shoreline and flood-prone areas, floodplain requirements that were not addressed up front. Build the plan-review time into the schedule and confirm the checklist with the Building Department before filing.
Every permit carries an expiration date set by Town of Smithtown, which may void a permit if work does not start in time; confirm the expiry on phased or delayed work. Permit validity in New York
Inspections in Smithtown
Where a permit is required, standard checkpoints include footing and foundation, framing, rough-in electrical, plumbing and mechanical, insulation and Energy Code compliance, fire systems on commercial work, and final, with a certificate of occupancy before use. The department inspects to the approved plans and reviews drainage and coastal conditions where they apply.
New York inspections are made against the code edition that applied to the permit application, so the approved plans and the Energy Code documentation need to be on site for the inspector to check against. Local code enforcement officials are certified by the state, and the municipality reports its enforcement activity to the Department of State. Confirm the notice the Building Department needs and schedule around its inspection windows.
Do not cover work before the required inspection has been approved. Keep the issued permit, the approved plans, product listings, Energy Code documentation and your correction responses available on site.
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Get a free quote →Smithtown permit search and official resources
Permit records in New York sit with the local authority that issued them. Where the Town of Smithtown Building Department is the authority for the Town of Smithtown outside its incorporated villages, it holds the building permit, the inspection history and the certificate of occupancy or compliance. If you are buying, refinancing or renovating, confirm that past work was permitted rather than assuming it was — open permits and missing certificates are a common closing problem in this state.
Confirm the authority having jurisdiction first. New York enforces one statewide Uniform Code outside New York City, but towns, villages and cities each administer it with their own local law, fee schedule and staffing, so the requirements that apply vary by parcel — and a village inside a town is its own authority. Confirm current requirements, fees and review turnaround for your filing date.
These are the primary sources behind this guide. Codes, fee schedules and procedures change — confirm the position for your filing date.
- Town of Smithtown Building Department
- NYS Uniform Fire Prevention and Building Code
- NYS State Fire Prevention and Building Code Council
- NYS Division of Building Standards and Codes
- Suffolk County Division of Consumer Affairs
Frequently asked questions
Who issues building permits in the Town of Smithtown?
The Town of Smithtown Building Department at 23 Redwood Lane, behind Town Hall (631-360-7520), for the unincorporated town. The three incorporated villages inside the town — Head of the Harbor, Nissequogue and the Village of the Branch — run their own building departments, so confirm the jurisdiction first.
Inspections are where schedules slip.
Get a free quote →How do I know if I am in a village?
If the parcel sits inside an incorporated village such as the Village of the Branch or Head of the Harbor, you file with that village rather than the town.
Do I need a contractor licence?
New York has no statewide contractor licence. Home improvement contractors working in the town need a Suffolk County Home Improvement licence from the county Department of Labor, Licensing and Consumer Affairs.
What about the Nissequogue corridor?
River, harbour and wetland parcels along the Nissequogue can carry drainage, wetland and coastal conditions that the department reviews alongside the building permit.
Do I need stamped drawings?
Commercial work and larger residential work require drawings stamped by a New York-licensed architect or professional engineer.
Which code edition applies?
The 2025 Uniform Code, administered by the town with local amendments adopted by local law.
Simplify Smithtown permitting with Alliance Permitting
Smithtown rewards confirming town versus village first, then clearing the Suffolk County licence and any coastal review before filing.
Trusted by leading builders, developers, and national contractors — 21+ years of filing in the jurisdictions we write about.
Contractors and builders choose Alliance for Smithtown because the work is done by people who have stood at the counter:
- We confirm whether a parcel is town or incorporated village before filing.
- We clear the Suffolk County Home Improvement licence up front.
- We check coastal, wetland and drainage conditions on the north shore.
- We assemble the stamped plan set the department requires.
- We coordinate the master plumber and other trade filings.
Alliance Permitting is a permit documentation and submission company in New York. We prepare your paperwork, file it correctly and coordinate with the permitting authority through issuance. We are not a contractor and we do not perform licensed plan review or inspections; that work stays with your licensed team and the jurisdiction.
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Let Alliance prepare, file, and track your Smithtown permits while your crew stays on the job.
More New York permitting guides
This guide is provided by Alliance Permitting for general information about Smithtown permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.