ICC P1 cheat sheet

A plumbing permit is required before installation, alteration, or replacement of a plumbing system; stopping leaks, clearing stoppages, and repairing existing fixtures or valves generally do not require a permit.

DWV water test: hold a 10-foot (3,048 mm) head of water for 15 minutes; DWV air test: maintain 5 psi (34.5 kPa) gauge pressure for 15 minutes.

Water distribution test: fill with potable water, raise to not less than the working pressure, and hold for 15 minutes with no leakage.

Building sewer test: use the same 10-foot water head or 5 psi air test for 15 minutes as for DWV piping.

Rough-in and final inspections are required; piping must not be concealed before the rough-in inspection is approved.

In flood hazard areas, plumbing fixtures, equipment, and connections must be installed to minimize flood damage and at the required elevation.

Occupant load and occupancy classification determine the minimum fixture count using the code fixture table.

Water service and building sewer separation: not less than 5 feet (1,524 mm) horizontally, and water pipe at least 12 inches (305 mm) above sewer at crossings.

Water closet spacing: at least 15 inches (381 mm) from centerline to any side wall or partition, with at least 30 inches (762 mm) of clear width.

Drainage fixture unit (DFU) values include water closet 3, lavatory 1, bathtub or shower 2, kitchen sink 2, and washing machine 3.

Water closets are limited to an average flush volume of 1.6 gallons (6 L) per flush.

Lavatory and kitchen faucets are limited to 2.2 gpm (8.3 L/min) at 60 psi; showerheads are limited to 2.5 gpm (9.5 L/min) at 80 psi.

Each fixture must be separately trapped, except fixtures with integral traps or listed combination fixtures.

Minimum fixture counts are based on occupancy classification and occupant load, with separate facilities for each sex where required.

Accessible fixtures require clear floor space and mounting heights; ICC A117.1 applies where accessible design is required.

A fixture's trap arm length and vent size depend on the fixture drain size and the slope of the trap arm.

Temperature and pressure relief valve: set to open at not more than 210°F (99°C) and 150 psi (1,034 kPa), and rated for the heater's capacity.

T&P discharge pipe: full-size, gravity flow, no traps, no valves, terminating not more than 6 inches (152 mm) above the floor or waste receptor.

Drain pan: at least 1.5 inches (38 mm) deep, at least 1.5 inches larger than the heater diameter, with a 3/4-inch (19 mm) drain.

Closed water system: thermal expansion tank or expansion control is required where a backflow preventer or check valve creates a closed system.

Garage installation: water heaters with ignition sources must be elevated 18 inches (457 mm) above the floor unless listed as flammable vapor ignition resistant.

Combustion air: confined spaces require two permanent openings sized per the combustion air provisions of the code.

Relief valve discharge must not be trapped or reduced, and the pipe material must be rated for the temperature and pressure.

Water heaters must be accessible for inspection, service, and relief valve replacement.

Maximum static pressure: 80 psi (552 kPa); a pressure-reducing valve is required where static pressure exceeds 80 psi.

Minimum residual pressure at fixtures: 8 psi (55 kPa) under peak demand conditions.

Water service pipe must be protected from freezing and buried below the local frost depth.

Backflow protection: air gap, reduced-pressure zone assembly, double check valve, or vacuum breaker, selected by hazard level at each cross-connection.

Water hammer arrestors are installed at quick-closing valves, solenoid valves, and laundry equipment.

Sizing uses water supply fixture units (WSFU) and developed length, including fitting allowances from the code tables.

A pressure booster is required where the available supply cannot meet the minimum fixture pressure.

Hot and cold water piping must be supported and protected from freezing, corrosion, and damage in concealed locations.

Slope: 1/4 inch per foot (2%) for pipe 2.5 inches and smaller; 1/8 inch per foot (1%) for pipe 3 inches and larger.

Cleanouts: required at the base of each stack, at changes of direction greater than 45 degrees, and at intervals not exceeding 100 feet (30,480 mm) in horizontal drains.

Horizontal 90-degree turns: use two 45-degree fittings or a long-radius bend; short-radius 90-degree fittings are prohibited in horizontal drainage.

A backwater valve is required where drainage fixtures are below the level of the next upstream manhole cover.

Building drain and building sewer minimum size is 4 inches (102 mm).

Drainage fixture units (DFU) are used to size building drains, sewers, stacks, and horizontal branches.

Sumps and sewage ejectors are required for below-grade fixtures that cannot drain by gravity.

Drainage piping must be tested and protected from freezing, corrosion, and structural damage.

Every trap must be vented, except listed exceptions such as some integral traps and combination fixtures.

Vent pipe must be not less than 1 1/4 inches (32 mm) nominal diameter.

Trap arm length at 1/4 inch per foot slope: 1 1/4-inch = 5 feet, 1 1/2-inch = 6 feet, 2-inch = 8 feet, 3-inch = 12 feet, 4-inch = 16 feet.

Vent terminals extend not less than 6 inches (152 mm) above the roof surface and above anticipated snow accumulation.

A vent must not serve as a drain; no trap or obstruction is permitted on a vent.

Vertical wet vent must be at least 2 inches (51 mm); bathroom group wet venting is permitted under code conditions.

Air admittance valves: not more than one per branch, installed in an accessible location, and not where positive pressure occurs.

A vent stack must extend to the outdoors and terminate above the roof; it may combine with a stack vent.

Trap seal: at least 2 inches (51 mm) and not more than 4 inches (102 mm) of water seal.

Prohibited traps: S-traps, bell traps, crown vents, and drum traps; use P-traps or listed traps.

Each fixture is separately trapped, except fixtures with integral traps or listed combinations.

Grease interceptors are required for commercial food preparation; they are not required for dwelling units and must be accessible and vented.

Sand and oil interceptors are required for repair garages, car washes, and similar discharges.

Trap primers are required for floor drains and traps subject to evaporation to maintain the trap seal.

Corrosive, hot, or high-temperature special wastes require neutralization, cooling, or dilution before discharge.

Interceptor sizing is based on flow rate and retention time; grease interceptor capacity may be based on fixture units or gallons per minute.

Storm drainage must be separate from sanitary drainage; no storm connection to the sanitary sewer is permitted.

Roof drains and leaders are sized using roof area, local design rainfall rate, and the code sizing table.

Secondary roof drainage, such as overflow scuppers or drains, is required to prevent ponding if primary roof drains become blocked.

Roof drain strainers must be provided and sized to handle the design flow.

Fuel gas piping is sized by the longest-length or branch-length method using Btu/hr load, pipe length, and allowable pressure drop.

A sediment trap (drip leg) is required at each appliance inlet, installed downstream of the shutoff valve.

A manual shutoff valve is required upstream of each appliance, in the same room, within 6 feet (1,829 mm) of the appliance.

Fuel gas piping test: not less than 3 psi (20.7 kPa) for 10 minutes, or 1.5 times the working pressure if higher; unions are prohibited in concealed locations.

Storm drainage must be separate from sanitary drainage; no storm connection to the sanitary sewer is permitted.

Roof drains and leaders are sized using roof area, local design rainfall rate, and the code sizing table.

Secondary roof drainage, such as overflow scuppers or drains, is required to prevent ponding if primary roof drains become blocked.

Roof drain strainers must be provided and sized to handle the design flow.

Fuel gas piping is sized by the longest-length or branch-length method using Btu/hr load, pipe length, and allowable pressure drop.

A sediment trap (drip leg) is required at each appliance inlet, installed downstream of the shutoff valve.

A manual shutoff valve is required upstream of each appliance, in the same room, within 6 feet (1,829 mm) of the appliance.

Fuel gas piping test: not less than 3 psi (20.7 kPa) for 10 minutes, or 1.5 times the working pressure if higher; unions are prohibited in concealed locations.

Storm drainage must be separate from sanitary drainage; no storm connection to the sanitary sewer is permitted.

Roof drains and leaders are sized using roof area, local design rainfall rate, and the code sizing table.

Secondary roof drainage, such as overflow scuppers or drains, is required to prevent ponding if primary roof drains become blocked.

Roof drain strainers must be provided and sized to handle the design flow.

Fuel gas piping is sized by the longest-length or branch-length method using Btu/hr load, pipe length, and allowable pressure drop.

A sediment trap (drip leg) is required at each appliance inlet, installed downstream of the shutoff valve.

A manual shutoff valve is required upstream of each appliance, in the same room, within 6 feet (1,829 mm) of the appliance.

Fuel gas piping test: not less than 3 psi (20.7 kPa) for 10 minutes, or 1.5 times the working pressure if higher; unions are prohibited in concealed locations.

Storm drainage must be separate from sanitary drainage; no storm connection to the sanitary sewer is permitted.

Roof drains and leaders are sized using roof area, local design rainfall rate, and the code sizing table.

Secondary roof drainage, such as overflow scuppers or drains, is required to prevent ponding if primary roof drains become blocked.

Roof drain strainers must be provided and sized to handle the design flow.

Fuel gas piping is sized by the longest-length or branch-length method using Btu/hr load, pipe length, and allowable pressure drop.

A sediment trap (drip leg) is required at each appliance inlet, installed downstream of the shutoff valve.

A manual shutoff valve is required upstream of each appliance, in the same room, within 6 feet (1,829 mm) of the appliance.

Fuel gas piping test: not less than 3 psi (20.7 kPa) for 10 minutes, or 1.5 times the working pressure if higher; unions are prohibited in concealed locations.

Storm drainage must be separate from sanitary drainage; no storm connection to the sanitary sewer is permitted.

Roof drains and leaders are sized using roof area, local design rainfall rate, and the code sizing table.

Secondary roof drainage, such as overflow scuppers or drains, is required to prevent ponding if primary roof drains become blocked.

Roof drain strainers must be provided and sized to handle the design flow.

Fuel gas piping is sized by the longest-length or branch-length method using Btu/hr load, pipe length, and allowable pressure drop.

A sediment trap (drip leg) is required at each appliance inlet, installed downstream of the shutoff valve.

A manual shutoff valve is required upstream of each appliance, in the same room, within 6 feet (1,829 mm) of the appliance.

Fuel gas piping test: not less than 3 psi (20.7 kPa) for 10 minutes, or 1.5 times the working pressure if higher; unions are prohibited in concealed locations.