Town of Smithtown, New York Building Permit Guide

All permits for new construction, additions and alterations in the Town of Smithtown, as well as sign permits, are issued by the Building Department, which also inspects work and issues certificates of occupancy. The office is at 23 Redwood Lane, Smithtown, NY 11787, open Monday through Friday 9:00 am to 4:00 pm, and 9:00 am to 3:00 pm from July 1 through August 31.

This guide covers the Town of Smithtown Building Department and the Town offices for zoning, planning, engineering and highway permits. For a project in one of the three villages, contact that village’s building department.

What requires a building permit in the Town of Smithtown?

The Town Code requires a building permit for any retaining wall with an exposed height of more than 30 inches. Common residential permits that can be applied for online include decks, fences, generators, HVAC, pools, solar panels and sheds over 144 sq. ft. and 12′ tall.

A regrading permit from the Engineering Department is generally needed where an existing elevation changes by more than four feet or earth is altered within ten feet of the property line. For a house built before building permits were required (1947), the Building Department issues a History Letter (Letter in Lieu); bring a recent survey and a copy of the assessor’s records.

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 the Town of Smithtown?

Zoning appeals and county health permits in the Town of Smithtown

Board of Zoning Appeals

The Board grants variances, special use permits and Certificates of Existing Use. It meets at 6:00 pm, typically on the second and fourth Tuesday of each month, at the Smithtown Senior Citizens Center, 420 Middle Country Road. Contact Planning and Community Development at (631) 360-7540.

Suffolk County Health Department permits

The Building Department points applicants to Suffolk County’s online Submission and Status terminal, which lists the status of all Health Department permits started since 2012.

Town of Smithtown permit costs and fees

The Residential Fee Schedule (revised 6-3-2026) is given to determine an approximate fee; the Town says to contact the Building Department for accurate fees. Its base fees:

The schedule’s other columns could not be matched reliably to their charges, so only the base fees are listed here. All permits expire one year from issuance and can be renewed once for 1/2 of the original fee; after that, a new application at current fees is required.

How to get a building permit in the Town of Smithtown

Every permit carries an expiration date set by the 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 the Town of Smithtown

Schedule building inspections by calling (631) 360-7522 during business hours or with the online form, and do not send duplicate requests; the CitySquared portal also schedules inspections. Building inspectors are available on request between 3:30 pm and 4:30 pm (3:00 pm to 3:30 pm in summer). Two inspections are included per category; each additional one costs $50. The Engineering Department inspects the engineering aspects of construction.

Official Town of Smithtown permitting resources

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
• Smithtown village building departments
• Smithtown online residential permits
• Smithtown residential fee schedule
• Smithtown Building Department FAQ
• Smithtown Board of Zoning Appeals
• Smithtown Planning & Community Development
• Smithtown Engineering Department
• Smithtown Highway Department

Frequently asked questions

Does the Town of Smithtown issue permits in Nissequogue or Head of the Harbor?

No. The Village of the Branch, the Village of Nissequogue and Head of the Harbor have their own building departments.

Does a retaining wall need a permit in Smithtown?

Yes, when it will have an exposed height of more than 30 inches.

My Smithtown house is older than 1947; how do I show it is legal?

Ask the Building Department for a History Letter (Letter in Lieu), bringing a recent survey and a copy of the assessor’s records.

Simplify Town of Smithtown permitting with Alliance Permitting

• Confirm the Town office for the parcel and the zoning, highway or fire approvals that go with the permit
• Prepare the application, surveys and plans and file them through the Town’s portal or counter
• Schedule the Town’s inspections and follow the permit through to the certificate of occupancy

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.

This guide is provided by Alliance Permitting for general information about Town of Smithtown permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.