NH Journeyman Plumber cheat sheet

Plumbing is the practice, materials, and fixtures used in installing, maintaining, extending, altering, or repairing piping for water, gas, sewage, and drainage within or adjacent to a building.

Water weighs about 62.4 lb per cubic foot; a column of water 1 ft high exerts 0.433 psi, so pressure in psi equals height in feet times 0.433.

Fixture unit (FU) values express the probable load of fixtures on supply and drainage systems; 1 FU approximates 1 cubic foot per minute of flow for drainage sizing.

A trap seal is maintained by a water depth of 2 to 4 inches; the minimum seal depth is 2 inches and the maximum is 4 inches.

Grade for drainage piping: 1/4 inch per foot for pipe 3 inches and smaller; 1/8 inch per foot is permitted for pipe 4 inches and larger where approved.

Flow velocity in water supply piping should generally stay below 8 fps in cold water and 5 fps in hot water lines to limit noise and erosion.

Common pipe materials: copper (Type L, M, K), PEX, CPVC, PVC, cast iron, and galvanized steel; each has distinct pressure, temperature, and joining limits.

Backflow prevention depends on an air gap or a mechanical device selected by hazard level: atmospheric vacuum breaker, pressure vacuum breaker, double check, or reduced pressure zone assembly.

A plumbing system has four parts: water supply, fixtures and fixture fittings, drainage, and venting; each must be designed and sized as a coordinated system.

Water closets are limited to 1.6 gallons per flush (gpf) maximum; high-efficiency models use 1.28 gpf or less.

Urinals are limited to 1.0 gpf maximum; waterless urinals use a sealed trap cartridge in place of a water seal.

Showerheads are limited to 2.5 gallons per minute (gpm) at 80 psi; kitchen faucets are limited to 2.2 gpm.

Lavatory faucets are limited to 2.2 gpm, and public lavatory faucets to 0.5 gpm at 60 psi.

Fixture clearances: 15 inches minimum from a water closet centerline to a side wall or partition, and 30 inches minimum clear width for the fixture space.

A water closet compartment must be at least 30 inches wide and 60 inches deep when a door is provided, with the door swinging outward.

Air gaps for fixture outlets: at least 1 inch or twice the effective opening of the supply fitting, whichever is larger, and never less than 1 inch above the flood-level rim.

Floor drains require a trap with a 2-inch minimum seal; trap primers or trap seal protection devices maintain the seal in infrequently used drains.

Drinking fountains must have a supply protected by an air gap or a listed backflow preventer, and the orifice must be above the flood-level rim.

A temperature and pressure relief (T&P) valve is required on every storage water heater; its rated capacity must equal or exceed the heater's input and its setpoint must not exceed 210°F or 150 psi.

The T&P relief valve discharge pipe must be full size, gravity-drained, terminate not more than 6 inches above the floor or outside, and never be trapped or reduced.

A thermal expansion tank is required on a closed water supply system to absorb expansion from heating; a check valve or backflow preventer creates a closed system.

Water heater seismic or thermal expansion control is separate from the T&P valve; the T&P valve protects against overpressure and overheating, not expansion volume.

Gas-fired water heaters in garages must have ignition sources elevated at least 18 inches above the floor unless listed as flammable vapor ignition resistant (FVIR).

A water heater drain pan is required where leakage could cause damage; the pan must be at least 1.5 inches deep and drained by gravity or a listed pump.

Combustion air for gas water heaters: 50 cubic feet per 1,000 Btu/hr input from indoor volume, or two permanent openings to outdoors sized at 1 square inch per 4,000 Btu/hr.

Storage water heaters must have the thermostat set no higher than 140°F for scald control; domestic hot water delivered to fixtures should not exceed 120°F at the point of use.

Tankless water heaters require minimum flow rates to fire and must be sized by simultaneous fixture demand plus incoming groundwater temperature rise.

Minimum static pressure at a fixture is 8 psi for flush tanks and 15 psi for flushometer valves; maximum static pressure at any fixture is 80 psi.

Where street pressure exceeds 80 psi, a pressure-reducing valve is required; where it is below 8 psi, a booster pump is required.

Water service pipe must be buried below the local frost depth; in New Hampshire this is typically 4 to 5 feet depending on location.

Sizing uses the demand load in fixture units converted to gallons per minute, then pipe size is selected from tables using developed length and pressure loss.

Developed length includes the actual pipe run plus equivalent lengths for fittings; a 90-degree elbow adds about 2 to 5 feet depending on size.

A water meter and main shutoff must be accessible; a bypass or full-open valve arrangement allows service without interrupting supply.

Hot water distribution should minimize dead legs; recirculation systems or point-of-use heaters reduce wait time and wasted water.

Copper Type M is permitted for above-ground domestic water; Type L is used for underground and higher-pressure service.

Drainage pipe slope: 1/4 inch per foot for 2-inch and smaller; 1/4 inch per foot for 3-inch; 1/8 inch per foot permitted for 4-inch and larger where approved.

A horizontal drainage branch must be vented; the trap arm length from fixture trap to vent is limited by pipe size (e.g., 1-1/2 inch pipe = 6 feet, 2 inch pipe = 8 feet, 3 inch pipe = 12 feet).

A vent stack must extend at least 6 inches above the roof and not less than 12 inches above the roof where the roof is used for other purposes.

Vent terminals must be at least 10 feet from any window, door, or air intake, and at least 3 feet above a roof within 10 feet of the vent.

A building drain is the lowest piping that receives the discharge from soil and waste stacks inside the building; it connects to the building sewer at least 2 feet outside the foundation.

A cleanout is required at the base of each soil or waste stack, at the building drain, and at intervals not exceeding 100 feet in horizontal runs.

Storm drainage must be separate from sanitary drainage; roof drains and area drains cannot connect to the sanitary sewer unless the system is a combined sewer.

A backwater valve is required on drainage fixtures installed below the elevation of the next upstream manhole or where the building drain is subject to backflow.

Vent pipe sizing depends on fixture units and developed length; an undersized vent causes gurgling, slow drains, and trap seal loss.

Gas piping must be sized by the longest length method or branch length method using the total Btu/hr input of connected appliances and the allowable pressure drop.

Natural gas is supplied at about 1,000 Btu per cubic foot; LP gas is about 2,500 Btu per cubic foot, so pipe sizing differs by fuel type.

A gas shutoff valve must be installed within 6 feet of each appliance and in the same room; a union or flanged connection allows appliance removal.

Sediment traps (drip legs) are required at each appliance unless the appliance is designed without one; the trap must be downstream of the shutoff valve.

Gas piping must be tested at 1.5 times the working pressure but not less than 3 psi for 10 minutes for low-pressure systems; higher-pressure systems require longer tests.

A gas appliance connector must not exceed 6 feet in length, must not pass through walls or floors, and must not be concealed.

Combustion air and venting for gas appliances: Category I appliances use natural draft venting; Category IV condensing appliances use direct venting with PVC or CPVC.

Gas piping must not be installed in a concealed location without protection, and it must not pass through a chimney, elevator shaft, or duct.

A gas leak test uses air or inert gas, never oxygen; a soap bubble solution or electronic detector locates leaks after isolation.

New Hampshire adopts the International Plumbing Code (IPC) as the state plumbing code, with amendments published in the New Hampshire Administrative Rules, Chapter Plc 300.

Plumbing work in New Hampshire requires a license issued by the Office of Professional Licensure and Certification (OPLC) under RSA 329-A.

A journeyman plumber license requires documented experience (typically 4 years) and passage of the journeyman examination; a master plumber license requires additional experience and examination.

Licenses must be renewed on a biennial cycle; continuing education hours are required for renewal and must be documented.

A plumbing permit must be obtained from the local authority having jurisdiction before work begins; emergency repairs may be permitted with follow-up inspection.

The state plumbing code applies to new construction, alterations, and repairs; existing installations that are not hazardous may remain in service.

Inspections are performed by local or state plumbing inspectors; work must be accessible for inspection before concealment.

Unlicensed plumbing work is subject to enforcement, fines, and permit revocation; homeowners may perform work only on their own residence where local rules allow.

Adopted code editions and amendments are published by the New Hampshire OPLC and take effect on the date specified in the rule; the most current edition governs.

Water pressure conversion: psi = feet of head × 0.433; feet of head = psi ÷ 0.433.

Fixture unit values represent probable flow; drainage and supply sizing tables use FU as the common basis.

Trap seal depth must be 2 to 4 inches; seals protect against sewer gas entry.

Backflow protection is selected by hazard level: air gap for high hazard, RPZ for high hazard, double check for low hazard.

Minimum drain slope is 1/4 inch per foot for small pipe and 1/8 inch per foot for large pipe where approved.

Water velocity limits: 8 fps cold, 5 fps hot, to control noise and erosion.

A plumbing system includes supply, fixtures, drainage, and venting; each component must be sized and installed as a system.

Water closet maximum flush: 1.6 gpf; high-efficiency: 1.28 gpf or less.

Urinal maximum flush: 1.0 gpf; waterless urinals use sealed trap cartridges.

Showerhead maximum flow: 2.5 gpm at 80 psi; kitchen faucet: 2.2 gpm; lavatory: 2.2 gpm.

Water closet clearance: 15 inches minimum from centerline to side wall; 30 inches minimum clear width.

Water closet compartment: 30 inches wide by 60 inches deep minimum, door swinging outward.

Air gap: at least 1 inch or twice the effective opening, never less than 1 inch above flood-level rim.

Floor drains require a 2-inch minimum trap seal; trap primers maintain seals in infrequently used drains.

T&P valve required on every storage water heater; setpoint not above 210°F or 150 psi.

T&P discharge pipe: full size, gravity-drained, terminates not more than 6 inches above floor, never trapped or reduced.

Thermal expansion tank required on closed systems with a check valve or backflow preventer.

Gas water heaters in garages: ignition sources elevated at least 18 inches unless FVIR listed.

Drain pan: at least 1.5 inches deep, drained by gravity or a listed pump.

Combustion air: 50 cubic feet per 1,000 Btu/hr from indoor volume, or two openings at 1 square inch per 4,000 Btu/hr.

Domestic hot water delivered to fixtures should not exceed 120°F at the point of use for scald control.

Minimum fixture pressure: 8 psi for flush tanks, 15 psi for flushometer valves; maximum 80 psi.

Pressure-reducing valve required above 80 psi; booster pump required below 8 psi.

Water service buried below frost depth; in New Hampshire typically 4 to 5 feet.

Developed length includes pipe run plus equivalent lengths for fittings; 90-degree elbows add 2 to 5 feet.

Water meter and main shutoff must be accessible; bypass allows service without interrupting supply.

Hot water recirculation or point-of-use heaters reduce dead legs and water waste.

Copper Type M is permitted above ground; Type L is used underground and for higher-pressure service.

Drain slope: 1/4 inch per foot for 3-inch and smaller; 1/8 inch per foot for 4-inch and larger where approved.

Trap arm length: 1-1/2 inch pipe = 6 feet, 2 inch = 8 feet, 3 inch = 12 feet.

Vent stack must extend at least 6 inches above the roof; 12 inches where the roof is used for other purposes.

Vent terminal must be at least 10 feet from windows, doors, and air intakes.

Building drain connects to building sewer at least 2 feet outside the foundation.

Cleanouts required at the base of each stack, at the building drain, and every 100 feet in horizontal runs.

Storm drainage must be separate from sanitary drainage; backwater valves required where fixtures are below the upstream manhole elevation.

Gas piping sized by longest length method or branch length method using total Btu/hr input and allowable pressure drop.

Natural gas: about 1,000 Btu per cubic foot; LP gas: about 2,500 Btu per cubic foot.

Gas shutoff valve within 6 feet of each appliance and in the same room; union or flanged connection allows removal.

Sediment trap required at each appliance unless designed without one; located downstream of the shutoff valve.

Low-pressure gas test: 1.5 times working pressure, not less than 3 psi, for 10 minutes.

Appliance connector: maximum 6 feet, must not pass through walls or floors, must not be concealed.

Gas leak testing uses air or inert gas, never oxygen; soap solution or electronic detector locates leaks.

New Hampshire adopts the International Plumbing Code with amendments in Administrative Rules Chapter Plc 300.

Plumbing work requires a license issued by the OPLC under RSA 329-A.

Journeyman plumber license requires documented experience (typically 4 years) and passage of the journeyman examination.

Licenses renew biennially; continuing education hours are required and must be documented.

A plumbing permit must be obtained from the local authority having jurisdiction before work begins.

Inspections must occur before concealment; work must be accessible for inspection.

Unlicensed plumbing work is subject to enforcement, fines, and permit revocation.

Plumbing includes supply, fixtures, drainage, and venting; each part must be sized as a coordinated system.

Water weighs 62.4 lb per cubic foot; 1 foot of head equals 0.433 psi.

Fixture units express probable load; 1 FU approximates 1 cubic foot per minute of drainage flow.

Trap seal depth must be 2 to 4 inches to prevent sewer gas entry.

Minimum drain slope is 1/4 inch per foot for small pipe; 1/8 inch per foot for large pipe where approved.

Backflow protection is selected by hazard level: air gap or RPZ for high hazard, double check for low hazard.

Water velocity limits: 8 fps cold, 5 fps hot, to control noise and erosion.

Water closet maximum flush: 1.6 gpf; high-efficiency models use 1.28 gpf or less.

Urinal maximum flush: 1.0 gpf; waterless urinals use a sealed trap cartridge.

Showerhead maximum flow: 2.5 gpm at 80 psi; kitchen and lavatory faucets: 2.2 gpm.

Water closet clearance: 15 inches minimum from centerline to side wall; 30 inches minimum clear width.

Water closet compartment: 30 inches wide by 60 inches deep minimum, door swinging outward.

Air gap: at least 1 inch or twice the effective opening, never less than 1 inch above the flood-level rim.

Floor drains require a 2-inch minimum trap seal; trap primers maintain seals in infrequently used drains.

T&P valve required on every storage water heater; setpoint not above 210°F or 150 psi.

T&P discharge pipe: full size, gravity-drained, terminates not more than 6 inches above the floor, never trapped or reduced.

Thermal expansion tank required on closed systems with a check valve or backflow preventer.

Gas water heaters in garages: ignition sources elevated at least 18 inches unless FVIR listed.

Drain pan: at least 1.5 inches deep, drained by gravity or a listed pump.

Combustion air: 50 cubic feet per 1,000 Btu/hr from indoor volume, or two openings at 1 square inch per 4,000 Btu/hr.

Domestic hot water delivered to fixtures should not exceed 120°F at the point of use.

Minimum fixture pressure: 8 psi for flush tanks, 15 psi for flushometer valves; maximum 80 psi.

Pressure-reducing valve required above 80 psi; booster pump required below 8 psi.

Water service buried below frost depth; in New Hampshire typically 4 to 5 feet.

Developed length includes pipe run plus equivalent lengths for fittings; 90-degree elbows add 2 to 5 feet.

Water meter and main shutoff must be accessible; bypass allows service without interrupting supply.

Hot water recirculation or point-of-use heaters reduce dead legs and water waste.

Copper Type M is permitted above ground; Type L is used underground and for higher-pressure service.

Drain slope: 1/4 inch per foot for 3-inch and smaller; 1/8 inch per foot for 4-inch and larger where approved.

Trap arm length: 1-1/2 inch pipe = 6 feet, 2 inch = 8 feet, 3 inch = 12 feet.

Vent stack must extend at least 6 inches above the roof; 12 inches where the roof is used for other purposes.

Vent terminal must be at least 10 feet from windows, doors, and air intakes.

Building drain connects to building sewer at least 2 feet outside the foundation.

Cleanouts required at the base of each stack, at the building drain, and every 100 feet in horizontal runs.

Storm drainage must be separate from sanitary drainage; backwater valves required where fixtures are below the upstream manhole elevation.

Gas piping sized by longest length method or branch length method using total Btu/hr input and allowable pressure drop.

Natural gas: about 1,000 Btu per cubic foot; LP gas: about 2,500 Btu per cubic foot.

Gas shutoff valve within 6 feet of each appliance and in the same room; union or flanged connection allows removal.

Sediment trap required at each appliance unless designed without one; located downstream of the shutoff valve.

Low-pressure gas test: 1.5 times working pressure, not less than 3 psi, for 10 minutes.

Appliance connector: maximum 6 feet, must not pass through walls or floors, must not be concealed.

Gas leak testing uses air or inert gas, never oxygen; soap solution or electronic detector locates leaks.

New Hampshire adopts the International Plumbing Code with amendments in Administrative Rules Chapter Plc 300.

Plumbing work requires a license issued by the OPLC under RSA 329-A.

Journeyman plumber license requires documented experience (typically 4 years) and passage of the journeyman examination.

Licenses renew biennially; continuing education hours are required and must be documented.

A plumbing permit must be obtained from the local authority having jurisdiction before work begins.

Inspections must occur before concealment; work must be accessible for inspection.

Unlicensed plumbing work is subject to enforcement, fines, and permit revocation.

Plumbing systems include water supply, fixtures, drainage, and venting, each sized and installed as a coordinated whole.

Water pressure conversion: 1 foot of head equals 0.433 psi; 1 psi equals 2.31 feet of head.

Fixture units express probable load; drainage sizing and supply sizing both use FU values as a common basis.

Trap seal depth must be 2 to 4 inches; the seal prevents sewer gas from entering the building.

Minimum drain slope is 1/4 inch per foot for 3-inch and smaller pipe; 1/8 inch per foot is permitted for 4-inch and larger where approved.

Backflow protection is chosen by hazard level: air gap or RPZ for high hazard, double check for low hazard.

Water velocity limits are 8 fps in cold water and 5 fps in hot water to control noise and erosion.

Water closet maximum flush: 1.6 gpf; high-efficiency models use 1.28 gpf or less.

Urinal maximum flush: 1.0 gpf; waterless urinals use a sealed trap cartridge.

Showerhead maximum flow: 2.5 gpm at 80 psi; kitchen and lavatory faucets: 2.2 gpm.

Water closet clearance: 15 inches minimum from centerline to side wall; 30 inches minimum clear width.

Water closet compartment: 30 inches wide by 60 inches deep minimum, door swinging outward.

Air gap: at least 1 inch or twice the effective opening, never less than 1 inch above the flood-level rim.

Floor drains require a 2-inch minimum trap seal; trap primers maintain seals in infrequently used drains.

T&P valve required on every storage water heater; setpoint not above 210°F or 150 psi.

T&P discharge pipe: full size, gravity-drained, terminates not more than 6 inches above the floor, never trapped or reduced.

Thermal expansion tank required on closed systems with a check valve or backflow preventer.

Gas water heaters in garages: ignition sources elevated at least 18 inches unless FVIR listed.

Drain pan: at least 1.5 inches deep, drained by gravity or a listed pump.

Combustion air: 50 cubic feet per 1,000 Btu/hr from indoor volume, or two openings at 1 square inch per 4,000 Btu/hr.

Domestic hot water delivered to fixtures should not exceed 120°F at the point of use.

Minimum fixture pressure: 8 psi for flush tanks, 15 psi for flushometer valves; maximum 80 psi.

Pressure-reducing valve required above 80 psi; booster pump required below 8 psi.

Water service buried below frost depth; in New Hampshire typically 4 to 5 feet.

Developed length includes pipe run plus equivalent lengths for fittings; 90-degree elbows add 2 to 5 feet.

Water meter and main shutoff must be accessible; bypass allows service without interrupting supply.

Hot water recirculation or point-of-use heaters reduce dead legs and water waste.

Copper Type M is permitted above ground; Type L is used underground and for higher-pressure service.

Drain slope: 1/4 inch per foot for 3-inch and smaller; 1/8 inch per foot for 4-inch and larger where approved.

Trap arm length: 1-1/2 inch pipe = 6 feet, 2 inch = 8 feet, 3 inch = 12 feet.

Vent stack must extend at least 6 inches above the roof; 12 inches where the roof is used for other purposes.

Vent terminal must be at least 10 feet from windows, doors, and air intakes.

Building drain connects to building sewer at least 2 feet outside the foundation.

Cleanouts required at the base of each stack, at the building drain, and every 100 feet in horizontal runs.

Storm drainage must be separate from sanitary drainage; backwater valves required where fixtures are below the upstream manhole elevation.

Gas piping sized by longest length method or branch length method using total Btu/hr input and allowable pressure drop.

Natural gas: about 1,000 Btu per cubic foot; LP gas: about 2,500 Btu per cubic foot.

Gas shutoff valve within 6 feet of each appliance and in the same room; union or flanged connection allows removal.

Sediment trap required at each appliance unless designed without one; located downstream of the shutoff valve.

Low-pressure gas test: 1.5 times working pressure, not less than 3 psi, for 10 minutes.

Appliance connector: maximum 6 feet, must not pass through walls or floors, must not be concealed.

Gas leak testing uses air or inert gas, never oxygen; soap solution or electronic detector locates leaks.

New Hampshire adopts the International Plumbing Code with amendments in Administrative Rules Chapter Plc 300.

Plumbing work requires a license issued by the OPLC under RSA 329-A.

Journeyman plumber license requires documented experience (typically 4 years) and passage of the journeyman examination.

Licenses renew biennially; continuing education hours are required and must be documented.

A plumbing permit must be obtained from the local authority having jurisdiction before work begins.

Inspections must occur before concealment; work must be accessible for inspection.

Unlicensed plumbing work is subject to enforcement, fines, and permit revocation.