Adoption
What Maine actually adopted
The Plumbers’ Examining Board adopted the 2021 Uniform Plumbing Code,
published by IAPMO (29th edition, third printing), as the standard for plumbing installations
in Maine. The adoption lives in board rule 02-395 CMR Ch. 4 § 1, took effect
January 1, 2022, and replaced the prior Chapter 4 that had adopted the 2015 UPC.
Two points people routinely get wrong:
- Maine is a UPC state, not an IPC state. The International Plumbing Code has never been adopted for Maine internal plumbing. Details differ between the two model codes (venting, fixture unit tables, trap rules), so referencing IPC sections on a Maine job is a fast way to fail inspection.
- The UPC only counts as amended. Compliance means the UPC plus Maine’s exclusions and amendments in Chapter 4, plus Title 32 Chapter 49, plus board rules, plus any applicable municipal ordinance. Reading the bare IAPMO book without the Maine amendment document gives you the wrong code.
Scope
What the code covers
Following UPC §101.2, the code applies to the erection, installation, alteration, repair, relocation, replacement, addition to, use, and maintenance of plumbing systems. In practice that spans:
- Water distribution — hot and cold potable supply, backflow protection, water heaters’ piping and safety devices;
- Drain-waste-vent (DWV) systems — sanitary drainage, traps, venting, cleanouts;
- Fixtures and fixture fittings;
- Building sewers and connections to public or private disposal, up to the jurisdictional handoff with the Subsurface Wastewater Disposal Rules;
- Indirect wastes, interceptors, and specialty piping addressed in the adopted chapters.
Maine notably does not adopt several UPC chapters wholesale. Among the carve-outs: the board has historically declined UPC provisions such as residential fire sprinklers (§612.0 in prior editions) and does not adopt the UPC’s health-care-facilities chapter (Chapter 13) or the model code’s fuel gas chapter — gas piping in Maine belongs to the Maine Fuel Board’s rules, not the plumbing code. See the Chapter 13 page for why that number keeps coming up.
Structure
How the adopted code is organized
| UPC chapter | Subject | Maine posture |
|---|---|---|
| 1 — Administration | Permits, enforcement, inspections | Heavily amended to match Maine statute: permit authority, exempt work, and the homeowner exemption are rewritten in Ch. 4. |
| 2 — Definitions | Terms | Adopted with Maine additions. |
| 3 — General Regulations | Workmanship, protection, testing | Adopted; freeze-protection expectations read strictly in Maine. |
| 4 — Fixtures | Fixtures & fittings | Adopted with amendments. |
| 5 — Water Heaters | Installation, T&P relief | Adopted; note licensing interplay with oil/gas technicians under Title 32 Ch. 139. |
| 6 — Water Supply | Distribution, backflow | Adopted with amendments. |
| 7 — Sanitary Drainage | DWV sizing, materials | Adopted with amendments; some model tables and permit provisions not adopted. |
| 8 — Indirect Wastes | Air gaps, receptors | Adopted. |
| 9 — Vents | Venting systems | Adopted with signature Maine amendments — the future-vent rule and taller roof terminations for snow. See Maine amendments. |
| 10 — Traps & Interceptors | Trap seals, grease | Adopted. |
| 11 — Storm Drainage | Roof/area drains | Adopted with amendments. |
| 12–14 & appendices | Fuel gas, health care, firestop, appendices | Generally not adopted — covered by other Maine authorities or excluded. |
Plain-language guide, not legal advice. This site summarizes Maine plumbing statutes, board rules, and the adopted plumbing code for general information. Code editions, amendments, and fees change; municipalities may apply stricter local requirements. Always confirm current requirements with the Maine Plumbers’ Examining Board, your Local Plumbing Inspector (LPI), and the adopted code text before performing or specifying work.