Plumbing fixture

However, water closets and showers (that are not in bathtubs) usually lack this feature because their drains normally cannot be stopped.

In some occasional cases, a sink may have both a potable (drinkable) and a non-potable water supply.

Floor-mounted water closets seal to the toilet flange of the drain pipe by means of a wax ring.

Each fixture drain, with exceptions, must be vented so that negative air pressure in the drain cannot siphon the trap dry, to prevent positive air pressure in the sewer from forcing gases past the water seal, and to prevent explosive sewer gas buildup.

In public facilities, the trend is toward sensor-operated (automatic) fixtures that improve hygiene and save money.

For example, sensor operated automatic-flush urinals have fewer moving parts, reduce wear, and tend to last longer than manual-flush valves.

Sensor-operated soap and shampoo dispensers reduce waste and spills that might otherwise represent a slippage hazard.

Construction companies on cost-plus contracts may actually favor these fixtures for this reason, although their clients may not.

The additional complexity of these fixtures also complicates repairs, particularly the diagnosis of malfunctions causing unexpected flushing.