Where the sediment comes from
Heating water drives dissolved minerals out of it, and they settle to the bottom of the tank as scale and grit. Hard water produces more of it, and the layer grows every year the tank is not flushed.
Why it matters
- The heater works harder and uses more energy to heat through the layer
- The bottom of the tank runs hotter, which shortens its life
- Less usable volume means hot water runs out sooner
- In electric heaters, the lower element can burn out in the buildup
What you can do
Flushing the tank through its drain valve removes loose sediment. If the tank has not been flushed in years, the buildup may be hardened and the drain valve may clog, which is worth knowing before starting.
When professional help makes sense
If flushing does not quiet the heater, if it is older and has never been maintained, or if you see rust-colored water or moisture at the base, have it assessed. Heavy sediment in an aging tank is often a sign that replacement is near.