A constantly running cistern wastes water and can run a household water meter up significantly, particularly in metered London properties. The cause is usually a failed flush valve seal that allows water to seep continuously into the pan, or an inlet valve that does not shut off cleanly when the cistern reaches its operating level. Worn rubber diaphragms, limescale on valve seats and degraded float assemblies are common in hard water areas. The result is a permanent trickle visible at the rear of the pan and an inlet valve that hisses or refills intermittently. Building Regulations and the Water Supply (Water Fittings) Regulations 1999 require fittings to be water efficient and free of waste. Engineers usually address common causes by replacing the flush valve, inlet valve washers or the float assembly.
Constant running cistern
Toilet cistern that runs continuously due to a failed flush valve or float seal.
