Plumbing Drainage Fittings

The fitting shown and discussed below are some of the common fittings you would use to construct any DVW (drainage waste and vent) system. They may be made of different materials; such as: copper, ABS, PVC or cast iron and employ different joining methods but their shape will be roughly the same.

Sanitary tee In drainage, sanitary tee's (usually just called a tee) are always installed as the picture shows it, with the curved part of the tee connecting a horizontal pipe to a vertical pipe. In venting a tee may be installed on the horizontal to connect a vertical vent.
Wye Wye's are used to connect both horizontal to horizontal and horizontal to vertical pipes. Often used in combination with a 45 degree fitting.
90 degree Not to be used at the bottom of a vertical drainage pipe on sizes smaller than 4".
45 degree Are commonly used in a DWV system to gradually change direction of flow, such as at the base of a stack. They are also often used in combination with a wye.
22.5 degree Not commonly used but may help create difficult offsets.
Coupling Used to connect two sections of pipe.
P-trap Used at each plumbing fixture to prevent sewer gasses from escaping by keeping a water seal in the trap.
Trap adapter Used to connect the fixture outlet pipe (tail piece) to the trap.
Double wye Same as a wye but typically used to connect back to back fixtures.
Double sanitary tee Can only be used on the vertical and will require a cleanout above the flood level rim of the fixtures connected to it.
Reducer Used to reduce upstream pipe size.
Bushing Same as a reducer but fits inside the hub of another fitting.
Plug Plugs are commonly installed as an access port (clean out) at various points in a DWV system.
Cap Used to keep an air tight seal on an unused pipe end.
Backwater valve Used on below grade drainage pipes to protect from sewer back-ups. To learn more see: Backwater valves.
Clean out Must be installed to allow cleaning of the drainage system. To learn more see: clean outs
Toilet flange Used to mount a water closet to. See installing a water closet.