All plumbing fixtures shall be provided with approved drains and vents. Vents shall be connected to the venting system for the building or where installed compatible with the listing approved air admittance valves may be used.


Approved water piping materials include welded or seamless copper tubing (WK, WL, WM, K, L or M), chlorinated polyvinyl chloride (CPVC), cross-linked polyethylene (PEX) and other materials as listed in the code.

Underground building drain and vent piping may be ABS plastic, polyvinyl chloride (PVC-Type DWV) and other materials as listed in the code.

Above ground sanitary drains and vent piping may be ABS plastic, polyvinyl chloride (PVC-Type DWV) and other materials as listed in the code. All piping materials shall be labeled with the manufacturer’s mark or name and the quality or grade of the product.

Access – valves and cleanouts

The code requires that access for maintenance and repair be maintained for plumbing drain clean-outs and floor drains. A door or a re-moveable panel is acceptable means for providing access.

Venting – air admittance valve

Where plumbing fixtures are installed for kitchenettes, bathrooms, and sinks, venting of the fixtures is required. Venting prevents trap siphonage, and helps wastes drain more efficiently. An air admittance valve may be used for fixture venting. Air admittance valves must remain accessible for inspection and maintenance and may not be concealed within walls (an access panel is permitted). Install the valves a minimum 4 inches above the horizontal branch drain of the fixture being vented. Stack type air-admittance valves must be installed at least 6 inches above the flood level rim of the highest fixture being vented.

Backwater Valve

Backwater valves are required where plumbing fixtures are installed in a basement and the flood level rim of the fixtures are located below the elevation of the next upstream manhole cover. Normally, this means all basement plumbing fixtures must be protected by a backwater valve. This valve must be installed in the branch drain line serving only the basement fixtures. It should not have other fixtures from upstairs passing through it. Access is required for routine maintenance of the valves.

Common Plumbing Requirements That Get Overlooked:

  • The minimum slope for drain lines is ¼” of fall for each 12” of run for drain pipe that is 2 inches or smaller, and must slope at least 1/8” of fall for each 12” of run for drain pipe that is 2.5 inches or larger.
  • Access panels must be provided for hydro massage bathtubs and air admittance valves (stud or vents) as required by the manufacturer.
  • An individual shutoff valve is required on the fixture supply water pipe to each plumbing fixture other than a bathtub or a shower.
  • All shower control valves must be the anti-scald type (pressure balance, thermostatic mixing, or combination pressure balance/thermostatic mixing per ASSE 1016).
  • Some municipalities require the use of purple primers and solvent cements for PVC drain waste and vent piping connections.
  • ALWAYS follow the manufacturers’ installation instructions.