Control stop (supply stop)A small valve that shuts off or limits the water supply.
Flush valve (flushometer)It lets a set amount of water through, then shuts itself off.
HandlePushed to start a flush.
Vacuum breakerIt keeps used water from being siphoned back into the supply.
Coupling nutIt joins the flush pipe to the spud.
The fixture 6
Inlet spud (top spud)The fitting on the fixture where the flush water enters.
RimThe raised edge round the bowl's top and sides.
BowlThe hollow that the flush water rinses.
StrainerIt covers the waste outlet and keeps solid objects out.
LipThe front edge of the bowl.
TrapA bend that stays full of water, keeping sewer gas out.
At the wall 4
Supply pipeIt brings water from the building to the control stop.
Wall hangerA bracket on the wall that the urinal hangs on.
Outlet connectionWhere the urinal joins the waste pipe in the wall.
Waste pipe (drain pipe)It carries the waste away to the sewer.
How this list was compiled: Every name checked on 2026-09-30, a name kept only where two independent sources use it. Wikipedia, Urinal, Flushometer and Vacuum breaker (https://en.wikipedia.org/wiki/Urinal, https://en.wikipedia.org/wiki/Flushometer, https://en.wikipedia.org/wiki/Vacuum_breaker); US Army, FM 3-34.471, Plumbing, Pipe Fitting, and Sewerage (2001), chapters 4, 8 and 9 (https://archive.org/details/FM_3_34_471_P_2001); US Navy, Utilitiesman 3 and 2 (1973), chapter 4 (https://archive.org/details/ERIC_ED097442); one fixture maker's urinal sheets and urinal flush valve instructions (https://archive.org/details/manualzilla-id-7077840, https://archive.org/details/manualsbase-id-184133, https://archive.org/details/manualsbase-id-175799, one company, one source); a second maker's urinal flush valve instructions (https://archive.org/details/manualsbase-id-262373); a third maker's urinal guide (https://archive.org/details/manualsbase-id-253097). The makers' documents were read as archive.org full text for their part names only. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry; a schematic of no maker's product, nothing traced. Licence: own work
How it works
A wall-hung urinal is flushed by a valve on the pipe above it, with no tank. The first drawing shows the fixture and its flush valve from the front. The second cuts it through from the side to show the trap and the pipes.
Read the full guide
From the supply to the bowl
Water comes along the supply pipe to the control stop and into the flush valve. Pushing the handle lets a set amount run down past the vacuum breaker, through the coupling nut and the inlet spud, and into the bowl.
From the bowl to the sewer
The water drains through the strainer into the trap, a bend that stays full to keep sewer gas out. It leaves at the outlet connection and runs down the waste pipe. A wall hanger holds the urinal on the wall.
Questions and answers
What are the parts of a urinal called?
The fixture has a bowl, a rim, a lip at the front, a strainer over the waste outlet and a trap. Above it are the flush valve with its handle, the control stop, the vacuum breaker and the spud where water enters.
What is the flush valve on a urinal?
The valve on top, also called a flushometer. It needs no tank: it uses the pressure in the supply pipe to send a set amount of water into the bowl, then shuts off by itself. Some have a sensor, not a handle.
What is a urinal spud?
The short fitting on the fixture where the flush pipe connects. A top spud urinal has it on top. A back spud urinal has it on the back, toward the wall.
What does the vacuum breaker do?
It sits on the flush pipe just under the valve. It prevents water from the fixture being siphoned backward into the drinking water supply if the pressure in the supply drops.