ME Plumber cheat sheet

Maine adopts the Uniform Plumbing Code (UPC) as its statewide plumbing code; local amendments cannot be less stringent than the state code.

A Maine journeyman plumber license requires documented experience plus passage of the journeyman exam; a master plumber license additionally qualifies the holder to contract for plumbing work.

Permits are required before installing, altering, or replacing plumbing systems; minor repairs such as replacing a faucet washer or a flush valve generally do not require a permit.

Inspections follow a defined sequence: rough-in (before covering walls), then final; concealed work must be inspected before it is enclosed.

Code defines terms precisely: "fixture unit" is a measure of load, "accessible" means reachable without damaging the structure, "readily accessible" means reachable without tools.

Minimum trap arm and vent distances, cleanout requirements, and fixture clearances are code-mandated values found in the UPC chapters, not design preferences.

Plumbing work on public water systems and cross-connection control is also governed by Maine drinking water rules in addition to the plumbing code.

Unlicensed plumbing contracting is a licensing violation enforceable by the state plumbing board; penalties include fines and permit denial.

Fixture unit (FU) values: water closet = 3 FU (4 in some tables), lavatory = 1 FU, bathtub/shower = 2 FU, kitchen sink = 2 FU, floor drain = 1-2 FU depending on size.

A drainage pipe must slope at the code minimum: 1/4 in per ft for pipes 2 1/2 in and smaller, 1/8 in per ft for pipes 3 in and larger.

A vertical vent must rise at least 6 in above the flood-level rim of the highest fixture served before it can offset horizontally.

Trap arm length limits: 1 1/4 in = 5 ft, 1 1/2 in = 6 ft, 2 in = 8 ft, 3 in = 12 ft, 4 in = 16 ft (UPC values); the vent must connect within that distance.

Each trap must be vented; a wet vent may serve only fixtures on the same floor and is limited in the number and type of fixtures it serves.

Building drain is the lowest piping inside the building; building sewer is the pipe from the building drain to the public sewer or private disposal system.

Cleanouts are required at the base of each soil stack, at changes of direction greater than 45 degrees in horizontal drains, and at intervals not exceeding 100 ft in horizontal runs.

A vent stack and stack vent serve different functions: the stack vent extends the soil stack above the roof, while a vent stack provides venting to lower fixtures.

Minimum fixture supply pressures: typically 8 psi at a flushometer valve and 8-15 psi at a fixture; the code sets minimum residual pressure at the most remote fixture.

Water service pipe sizing uses fixture units and the developed length of the system, with a pressure-loss table; a pressure-reducing valve is required when street pressure exceeds 80 psi.

Thermal expansion control is required on a closed system: install an expansion tank on the cold side downstream of a backflow preventer or check valve.

Backflow protection is required at cross-connections: an air gap is the highest protection, followed by a reduced pressure zone (RPZ) assembly, then a double check valve.

Hot water must be delivered at a minimum of 110 degrees F at fixtures; scald protection (tempering valve or anti-scald device) is required where water can exceed 120 degrees F.

A water heater must have a temperature and pressure relief valve piped full size to within 6 in of the floor or to a safe discharge point.

Water distribution piping must be supported: copper at intervals not exceeding 6 ft horizontal and 10 ft vertical; PEX per manufacturer listing and code support spacing.

Shock arrestors or air chambers are used to absorb water hammer at quick-closing valves and at the end of long runs.

A water closet must have a minimum 15 in clearance from its centerline to any side wall and 21 in of clear space in front of the bowl.

A lavatory must have at least 4 in of space from its centerline to a side wall and 15 in of clearance in front.

Every fixture must be individually trapped except where a listed fixture with an integral trap is used; fixtures must be accessible for cleaning and repair.

A dishwasher must have a backflow-preventing air gap or a high-loop drain; the drain hose must connect to the sink drain or disposal upstream of the trap.

A clothes washer standpipe must be at least 18 in and not more than 42 in above the trap weir, with a 2 in trap and a 2 in trap arm.

A water heater must be installed with a seismic strap in seismic zones and a drip pan where leakage could cause damage; combustion appliances need adequate combustion air and venting.

Gas-fired appliances require a sediment trap and a shutoff valve on the supply line, and the appliance connector must be listed and not concealed.

A floor drain must be trapped and vented; trap primers are required where the trap could evaporate and allow sewer gas to enter.