Plumbing advice · Boilers & Heating
How to Flush Sediment From a Water Heater
Sediment makes cylinders rumble, slows heating and kills elements.
Why sediment builds
Minerals drop out of heated water and settle at the base of the cylinder. The layer insulates the water from the heat source, so heating takes longer, costs more and the tank rumbles as steam bubbles fight through the silt.
The flush, in outline
Power and water off, hose on the drain valve, cylinder drained and refilled until it runs clear. On a vented cylinder it is an afternoon job for a confident DIYer; on an unvented cylinder the law and the safety controls make it an engineer job.
Prevention in hard water areas
Both our cities have hard water zones. A scale inhibitor on the cold feed and a yearly flush keep a cylinder efficient for decades, and both cost a fraction of one replacement element.
Need it done instead?