Nassau County Plumber License: Tri-Town Reciprocity, Town Exams, and Village Registration

Nassau County Doesn't Issue Plumber Licenses

This is the detail that confuses most plumbers searching for licensing information on Long Island. Nassau County, unlike neighboring Suffolk County, does not have a county-level plumbing licensing program. The county's Office of Consumer Affairs handles general contractor registrations, but structural plumbing — anything involving water supply lines, waste stacks, vent systems, or gas piping — falls entirely under the jurisdiction of individual towns and villages.

That means there's no single application, no single board, and no single exam for "Nassau County." Your licensing path depends on which town or village contains the job site.

The Three Towns and Their Licensing Boards

Nassau County is divided into three towns, each with its own plumbing examining board:

Town of Hempstead — The Building Department issues Master Plumber licenses. Candidates must demonstrate seven years of hands-on experience under a licensed plumber and pass the town's examining board exam. Licenses renew annually on a calendar-year cycle.

Town of North Hempstead — The Examining Board of Plumbers handles licensing. The experience requirement is the same — seven years under a licensed plumber. North Hempstead participates in the Tri-Town Reciprocity Agreement, which means plumbers licensed in Hempstead or Oyster Bay can apply for reciprocal credentials here without retaking an exam.

Town of Oyster Bay — The Department of Planning & Development oversees plumber licensing through the Plumbers' Examining Board. Seven years of experience under a licensed plumber is required. Like the other two towns, Oyster Bay participates in the Tri-Town reciprocity system.

How Tri-Town Reciprocity Works

The Tri-Town Reciprocity Agreement, established in 1969, is the closest thing Nassau County has to a unified licensing system. Under this framework:

1. You choose a "home" town — Hempstead, North Hempstead, or Oyster Bay — and sit for their Master Plumber exam to earn your Certificate of Competency.
2. Once your primary license is active, you can apply for reciprocal licenses in the other two towns without sitting for a new exam.
3. The reciprocal application requires a copy of your original Certificate of Competency, a Letter of Good Standing from your home town, proof of vehicle registration for commercial bumper decals ($10 per vehicle), and insurance certificates naming the reciprocal town as the certificate holder.

North Hempstead, for example, waives the exam for reciprocal applicants but requires a notarized Tri-Town Plumber Form.

The reciprocity agreement saves significant time and money — but it doesn't eliminate the administrative work. You still need to file separate applications, pay each town's registration fees, and maintain independent insurance certificates naming each town as the certificate holder.

The Village Problem

Here's where it gets complicated. Nassau County contains dozens of incorporated villages, and not all of them automatically honor town-issued licenses. Villages like Lynbrook and Great Neck operate their own plumber registration systems.

In Lynbrook, for example, a new two-year plumber license costs $200, and you must submit village-specific insurance endorsements even if you already hold a valid Hempstead license. Great Neck has a reciprocal agreement with all towns in Nassau County but still requires its own application.

Before starting work in any Nassau County village, contact the village building department directly to confirm whether they accept your town license or require separate local registration.

Insurance Requirements

Nassau County towns typically require general liability insurance of $500,000 to $1,000,000 per occurrence (the exact minimum varies by town), plus workers' compensation and disability insurance for businesses with employees. Sole proprietors without W-2 employees must file a CE-200 exemption certificate.

Each insurance certificate must name the specific town or village as the certificate holder. A policy listing "Town of Hempstead" won't satisfy North Hempstead's requirements — you need separate certificates for each jurisdiction.

NYC License Holders: You Still Need a Nassau License

A common misconception is that an NYC Master Plumber license covers all of New York. It doesn't. Your NYC DOB credential has zero legal standing in Nassau County. Working in any Nassau town without the appropriate local license constitutes unlicensed contracting — a misdemeanor that carries civil penalties and potential contract forfeiture.

The New York Plumber License Guide maps the Tri-Town reciprocity process step by step and includes the complete insurance and registration requirements for each Nassau County town, so you can plan your multi-jurisdiction licensing strategy before paying any fees.

See more New York guides →