ICC P2 cheat sheet

A plumbing permit is required before installing, altering, repairing, or replacing a plumbing system, except for minor work specifically exempted by the code.

Typical permit exemptions include clearing stoppages, replacing a faucet washer, and other minor repairs that do not change the piping arrangement.

Plans and specifications must be submitted for review when required by the code official, and installed work must match the approved plans.

Required inspections commonly include rough-in of water supply and drain-waste-vent piping, water heater installation, building sewer, and final inspection.

Drain-waste-vent piping must be tested before concealment; the code specifies water or air test methods, pressures, and durations.

A stop-work order may be issued for work that is unsafe, contrary to code, or performed without a permit, and work must stop until the order is rescinded.

The code official may approve alternative materials or methods when they are equivalent in quality, strength, effectiveness, fire resistance, durability, and safety.

A certificate of occupancy is not issued until the final plumbing inspection has been approved.

"Approved" means acceptable to the code official because the material, method, or product conforms to the code or an approved standard.

"Plumbing" includes the water supply and distribution pipes, fixtures, drainage pipes, vents, and related appurtenances installed in a building.

"Potable water" is water free from impurities in amounts that could cause disease or harmful physiological effects.

A "cross-connection" is any actual or potential physical connection between a potable water supply and a nonpotable source.

"Backflow" is the reverse flow of water or other substances into the potable water system from a nonpotable source.

An "air gap" is the unobstructed vertical distance between the lowest opening of a water outlet and the flood level rim of the fixture it supplies.

A "fixture unit" is a measure of the probable load that a plumbing fixture imposes on the drainage system or water supply system.

A "trap" is a fitting that retains a water seal to prevent sewer gas from entering a building.

"Developed length" is the length measured along the centerline of pipe and fittings, including allowances for fittings.

Water closets require at least 15 inches from centerline to sidewall, 15 inches between adjacent fixtures, and 21 inches in front of the fixture.

Each fixture trap must have a water seal of at least 2 inches and not more than 4 inches.

Water heaters require a temperature and pressure relief valve, and the discharge pipe must be full size, gravity-drained, and terminate in a safe location.

The relief valve discharge pipe must not be reduced in size and must not contain valves or traps.

Water heaters installed in garages must have ignition sources elevated at least 18 inches above the floor unless listed as flammable vapor ignition resistant.

Hose bibbs and similar outlets require backflow protection such as a vacuum breaker where a hose can be connected.

Grease interceptors are required for many food service establishments to separate fats, oils, and grease from wastewater before discharge.

Fixtures must be installed with clearance for cleaning and use, and fixtures must be accessible for inspection and repair.

Minimum fixture supply pressure is typically 8 psi for tank-type fixtures and 15 psi for flushometer valves.

Static water pressure exceeding 80 psi requires a pressure-reducing valve to protect the plumbing system.

Maximum water velocity in distribution piping is commonly 8 feet per second for cold water and 5 feet per second for hot water.

Backflow prevention must match the hazard; air gaps and reduced pressure zone assemblies provide high-hazard protection.

Water service pipes must be buried below the frost line or otherwise protected from freezing.

A thermal expansion tank is required on a closed water heater system to absorb expanded water and prevent excessive pressure.

Water distribution piping is sized using fixture units, developed length, pressure available, and elevation changes.

The water supply system must be tested under working pressure or with air, and leaks must be repaired before approval.

Horizontal drainage pipe must slope at least 1/4 inch per foot for 2 1/2 inch and smaller pipe, and 1/8 inch per foot for 3 inch and larger pipe.

Drainage pipe size must not be reduced in the direction of flow.

Trap seals must be at least 2 inches and not more than 4 inches deep.

The trap arm length between a trap and its vent is limited by code and depends on the trap size.

Cleanouts are required at the base of stacks, at changes of direction of 135 degrees or more, and at specified horizontal intervals such as every 100 feet.

Vent pipes must extend at least 6 inches above the roof and must be located away from windows, doors, and air intakes.

A wet vent serves as both a drain and a vent and is permitted only where the code allows and when properly sized.

A backwater valve may be required where fixtures are subject to sewage backflow from a surcharging public sewer.

Air admittance valves may be used only where permitted by the code and must be installed in accessible locations.

Storm water must discharge to an approved storm drainage system or receiving water and must not connect to a sanitary sewer unless an approved combined system exists.

Roof drains are sized using the roof area and the local design rainfall rate.

Roofs with parapet walls often require secondary drainage such as overflow drains or scuppers to handle rainwater if primary drains block.

Storm drainage piping must be sized and sloped so that water drains freely without ponding on the roof.

Sump pumps must discharge to an approved location and must not discharge to the sanitary sewer without approval.

Special plumbing systems such as nonpotable water systems must be identified and protected against cross-connections with potable water.

Subsoil drains collect groundwater and must discharge to an approved location.