Maine Plumbing Code

Which Code Maine Actually Uses

Maine adopted the 2021 Uniform Plumbing Code (UPC), published by the International Association of Plumbing and Mechanical Officials (IAPMO), effective January 1, 2022. But the state didn't adopt it wholesale. The Plumbers' Examining Board stripped out multiple chapters and amended others through Chapter 4 of its administrative rules.

Understanding what was excluded matters as much as understanding what was adopted — the exclusions define where plumbing jurisdiction ends and where other trade boards take over.

Key Exclusions and Amendments

Water heaters (Chapter 5) — mostly excluded. The full chapter is not adopted, except for a handful of structural and safety sections: applicability rules, first-hour rating tables, indirect-fired heater specs, single-wall heat exchangers, dielectric insulators, ground supports, drainage pans, and manufacturer-instruction compliance. The energy source and fuel connections are regulated separately — the Maine Fuel Board handles gas and oil-fired units, the Electricians' Examining Board handles electric units. A licensed plumber connects the potable water lines to a water heater, but the fuel or electrical connection requires a separate trade license.

Gas piping supports (Chapter 314.7) — excluded. Gas piping is regulated by the Maine Fuel Board and the Public Utilities Commission, not the Plumbers' Examining Board.

Medical gas and vacuum systems (Chapter 320.0) — excluded. These systems fall entirely outside plumbing board jurisdiction.

Ratproofing (Chapter 313.12.3) — excluded. Not part of state-level plumbing installations.

UPC appendices (Chapter 102.8) — not adopted. None of the UPC appendices apply in Maine unless the Board explicitly adopts a specific one.

Plan review fees and time limits (Chapter 104.3) — not adopted. Plan review procedures and fees are set at the local municipal level, not by the state code.

What the Amendments Change

Roughing-in definition (Chapter 220.0) — Amended to specifically define roughing-in as all plumbing system parts installable before fixtures go in: drainage, water supply, vent piping, and fixture supports. This matters for inspection sequencing — your rough-in inspection must happen before wall enclosure.

Construction documents (Chapter 104.3.1) — Local plumbing inspectors can require two or more sets of construction documents, engineering calculations, and isometric diagrams with a permit application.

Separate toilet facilities (Chapter 422.2) — Amended with specific exemptions: residential installations, occupancies with 10 or fewer people, business/mercantile occupancies with 50 or fewer, and eating establishments under Title 22, Section 1686 (where one multi-sex facility is allowed).

Jurisdictional Boundaries

The plumbing code governs potable water supply, drain-waste-vent (DWV) systems, and plumbing fixtures within a building up to the first point of ground entry. Beyond that:

• Septic systems fall under the Maine DHHS Division of Environmental Health and the Subsurface Wastewater Disposal Rules. A plumbing license alone doesn't authorize septic design or installation; those require the applicable DHHS credentials and coordination.
• Public utility connections from the property line to the main are governed by local utility districts.
• Fuel gas piping sits with the Maine Fuel Board.
• Electrical connections for plumbing equipment require an electrician's license.

Local municipalities enforce the adopted code through Local Plumbing Inspectors (LPIs), and some cities layer additional requirements on top. Code enforcement practices vary significantly — Portland processes permits through an online CSS portal, while small towns may have a plumbing inspector available only a few hours per month.

The Maine Plumber License Guide details both the state code framework and the municipal enforcement layer, so you know which authority governs each part of your project.

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