Sweep elbow

DWV elbows are usually long radius or sweep types, to reduce flow resistance and solids deposition when the direction of flow is changed. A well-designed system will often employ multiple 45° elbows in preference over 90° elbows (even sweep elbows), to reduce flow disruption as much as possible.

Central vacuum system inlet fittings are intentionally designed with a tighter radius of curvature than any other bends in the system. This is done to insure that if any vacuumed debris becomes stuck, it will jam right at the inlet, where it is easiest to discover and to remove.

Closet flange

The closet flange is the drain pipe flange to which a water closet (toilet) is attached. It is a specialized type of flange connection designed to sit flush with the floor, allowing a standard toilet to be installed above it.

Clean-outs

Clean-outs are fittings with removable elements that allow access to drains without requiring removal of plumbing fixtures. They are used for allowing an auger or plumber's snake to clean out a plugged drain. Clean-outs should be placed in accessible locations at regular intervals throughout a drainage system, often including outside the building, because clean-out augers have limited length. The minimum requirement is typically at the end of each branch in piping, just ahead of each water closet, at the base of each vertical stack, and both inside and outside the building in the building main drain/sewer. Clean-outs normally have screw-on caps or screw-in plugs. Clean-outs are also known as rodding eyes from the eye-shaped cover plates often used on external versions.

Trap primers

Trap primers regularly inject water into traps so that "water seals" are maintained, as necessary to keep sewer gases out of buildings. The trap primer must be installed in a readily available place for easy access for adjustments, replacement, and repair. Strictly speaking, a trap primer is a specialized valve, and it is usually connected to a clean water supply, in addition to a DWV system. Because of this dual connection, the design usually must be certified to resist accidental backflow of contaminated water.

Combo-Tee

A combination tee (combo tee) is a tee with a gradually curving center connecting joint. It is used in drain systems to provide a smooth, gradually curving path to reduce the likelihood of clogs, and to ease pushing a plumber's snake through a drain system. The "combo" is a combination of a wye and a 1/8 bend or 45° elbow.

Sanitary Tee

A sanitary tee is a tee with a curved center section designed to minimize the possibility of siphon action that could draw water out of a trap. The center connection is generally connected to the pipe which leads to a trap (the trap arm).

Double Sanitary Tee (Sanitary Cross)

Similar to a cross. This fitting differs from a standard cross in that two of the ports have curved inlets. The fitting has been used in the past for connecting the drains of back-to-back fixtures (such as back-to-back bathroom sinks). Some current codes (including the 2006 UPC) prohibit the use of this fitting for that purpose, instead requiring a special "double fixture fitting".[further explanation needed]

Wye fitting

A type of waste fitting tee which has the side inlet pipe entering at a 45° angle.

Double-tapped bushing

A double-tapped bushing is a fitting that has opposing threads on the inside diameter of the bushing.