Sediment gathering inside your water heater can cause a number of problems. Sediment can stick to the heating element and form a white scale. This scale interferes with heat transfer and reduces the heater's efficiency. If enough sediment settles at the bottom of the tank, the drain valve can become clogged. That's a potential safety hazard. Accumulation of settlement in the bottom of your water heater can be controlled with a simple periodic flushing.