The plumbing of the stable is not complete without the properly connected horse trough. The horse trough is generally made of cast iron, and may be provided with a standing overflow to guard against the overflowing of the fixture.

Its waste should be 2 in. in size, and its vent 1 1/2 in. The drainage pipes of stables are generally of cast iron, as the presence of strong acids in the waste soon causes wrought iron to deteriorate.