MA Plumber cheat sheet

The Uniform State Plumbing Code is 248 CMR 10.00; it is adopted by the Board of State Examiners of Plumbers and Gas Fitters and enforced locally by the municipal plumbing inspector.

A plumbing permit is required before installation, alteration, replacement, or repair of plumbing; only a licensed master plumber may take out the permit for plumbing work.

Standard inspection sequence: underground/slab inspection, then rough-in (frame) inspection, then final inspection after fixtures and trim are set.

Work may not be concealed until it has been inspected and approved; inspectors may issue stop-work orders or require exposure of covered work.

Drainage, waste, and vent systems are tested before rough-in approval, typically with a 10-foot head of water held at least 15 minutes, or an equivalent air test with a gauge.

Water distribution piping is tested hydrostatically at not less than normal working pressure and held long enough to show no pressure drop before approval.

Appeals of a local inspector's decision and requests for variances are filed with the Board of State Examiners of Plumbers and Gas Fitters.

Permit fees, plan review requirements, and inspection scheduling are set by each municipality within the state code framework.

Gas work requires its own license and, where required locally, a separate gas permit under 248 CMR 4.00 even when performed on the same job as plumbing.

Private fixture units: lavatory 1, bathtub or shower 2, kitchen sink 1.5, dishwasher 1.5, tank-type water closet 2.5, flushometer water closet 10, washing machine 4.

Sizing procedure: total the water supply fixture units, convert to probable demand in gallons per minute from the tables, then select pipe size for the developed length and allowable friction loss.

Residual pressure rules of thumb: at least 8 psi flowing at tank-type water closets and at least 15 psi at flushometer valves.

Minimum fixture branch sizes: 1/2 inch for lavatories and tank-type water closets; 1 inch for flushometer water closets.

Velocity in water distribution piping is generally limited to about 8 feet per second to control noise and pipe erosion.

Any connection that could allow backflow (hose bibs, boilers, irrigation, chemical dispensers, carbonators) requires an air gap, vacuum breaker, or reduced-pressure zone assembly.

Wetted surfaces of pipe, fittings, and fixtures must be lead-free, defined as not more than 0.25 percent lead by weighted average.

Water heaters need a temperature-and-pressure relief valve, a discharge pipe ending within 6 inches of the floor with an unthreaded end, and thermal expansion control on a closed system.

Developed length includes the equivalent length of fittings and valves, so added elbows and valves increase the required pipe size for a given load.

Drainage fixture units: water closet 4, kitchen sink 2, lavatory 1, bathtub 2, shower 2, floor drain 2, washing machine 2, dishwasher 2.

Slope: 1/4 inch per foot for pipe 2 1/2 inches and smaller; 1/8 inch per foot for pipe 3 inches and larger.

Trap seals must be 2 to 4 inches deep, and each trap must be protected by a vent with the trap arm limited in length by the fixture drain size.

A vent stack terminates in open air at least 6 inches above the roof surface, higher where snow depth requires, and clear of windows, doors, and air intakes.

Backwater valves are required where fixtures drain below the level of the public sewer or where sewer flooding is possible.

Cleanouts are required at the base of every stack, at the building drain, and at intervals not exceeding 100 feet on horizontal runs.

A trap that is set too far from its vent can siphon; the fixture drain length between trap and vent is limited by the pipe diameter.

Wet venting is allowed only for specific combinations, such as a lavatory wet-venting a water closet or bathtub, and the wet-vented section must be sized and limited in length.

Horizontal pipe must be supported at code intervals by material; cast iron, for example, is supported at intervals not exceeding 5 feet with support at each joint.

Massachusetts limits new water closets to 1.28 gallons per flush, below the federal maximum of 1.6 gallons per flush.

Water closet spacing: at least 15 inches from centerline to a side wall, at least 30 inches clear width, and at least 15 inches from the bowl front to any obstruction.

Food service establishments require a grease interceptor sized to the fixtures discharging fats, oils, and grease, with a flow-control fitting and proper venting.

Indirect waste must discharge through an air gap of at least twice the diameter of the receiving pipe, or at least 1 inch.

Floor drains and other infrequently used traps need trap primers or a trap-seal primer connection to prevent sewer gas from entering.

Water heater installation requires a relief valve, a drain pan piped to a safe location where leakage would cause damage, and an expansion tank on closed systems.

Dishwashers must be protected against backflow by an air gap or a listed backflow device on the water connection.

Accessible fixtures: grab bars at 33 to 36 inches above the floor, adequate turning space, and insulated or protected pipes under lavatories.

Fixtures must be listed and installed per manufacturer instructions; slip-joint tubular waste connections are allowed only where accessible for service.

Massachusetts gas fitting is governed by 248 CMR 4.00, which adopts NFPA 54 with state amendments; gas work requires a gas fitter license and a gas permit where required.

Approved piping materials include black steel, galvanized steel, copper, brass, corrugated stainless steel tubing, and polyethylene for underground use, each with specific restrictions.

Sizing uses the longest-length method with total connected Btu/hr input, gas specific gravity of 0.60, and the allowable pressure drop from the tables.

Pressure test: not less than 3 psi (or 1.5 times working pressure, whichever is greater) held at least 10 minutes with no loss for systems operating at 1/2 psi or less.

A sediment trap (drip leg) is required at each appliance, full size of the appliance connector, with a capped nipple at least 3 inches long.

A manual shutoff valve must be in the same room as the appliance and within easy reach; appliance connectors are limited in length and may not be concealed.

Gas piping may not run inside ducts, plenums, chimneys, elevator shafts, or other concealed inaccessible spaces; it must be sleeved where it passes through masonry or concrete.

Horizontal gas piping is supported at code intervals (about 6 feet for small sizes) and must not be supported from other piping or ductwork.

Underground gas piping must be coated or wrapped against corrosion and tested before backfilling.

Unconfined space rule: at least 50 cubic feet of volume per 1,000 Btu/hr of total input; smaller spaces are confined and need two permanent combustion air openings.

Outdoor air openings are sized at 1 square inch free area per 4,000 Btu/hr through vertical ducts, 1 square inch per 2,000 Btu/hr through horizontal ducts, and 1 square inch per 3,000 Btu/hr for a single opening.

Category I appliances operate with negative vent pressure and flue temperatures high enough to avoid condensation; they are typically vented by natural draft through listed Type B vent.

Vent connectors must slope upward toward the vent at not less than 1/4 inch per foot and be as short and direct as practical.

Gas vent termination must extend at least 3 feet above the highest point where it passes through the roof and at least 2 feet above any building portion within 10 feet.

Type B vent requires at least 1 inch of clearance to combustible materials.

A gas appliance may not be vented into a chimney serving a solid-fuel appliance or into a fireplace flue; relining with a listed liner may be required.

Draft hoods and draft diverters are part of the listed appliance and must not be modified or removed.

Massachusetts requires carbon monoxide alarms in dwellings that contain fossil-fuel appliances or attached garages.

License levels: registered apprentice, journeyman plumber, master plumber, and the corresponding gas fitter licenses; only a master may obtain permits and contract work.

Apprentices must work under the supervision of a licensed journeyman or master; supervision ratios and scope of work follow Board rules.

OSHA requires a protective system (sloping, shoring, or trench box) for excavations 5 feet deep or more where a cave-in hazard exists, with a ladder within 25 feet of travel.

Spoil and materials must be kept at least 2 feet back from the trench edge; utilities must be located before digging.

Massachusetts requires Dig Safe notification at least 72 hours before excavation so underground utilities can be marked.

Fall protection is required at 6 feet in construction, and all temporary 120-volt receptacles must have GFCI protection.

Lead-safe renovation rules apply to pre-1978 housing; lead abatement requires a licensed deleader in Massachusetts.

Written contracts should state scope, price, change-order procedure, warranty, and payment terms; mechanic's lien rights have short statutory deadlines.

Carry general liability insurance and workers' compensation coverage, and verify coverage before starting any job.