Deposits of lime and other sediments create a rock-hard layer in the bottom of the tank, and build up on electric heating elements!
Sediment eats away at the tank's protective inner lining and welds. Rust soon forms, and it's just a matter of time before a leak starts!
BAD: The tank "gets smaller."
As sediment builds up, there's less room to store hot water!
BAD: High-priced hot water!
Sediment buildup coats the electric heating elements and collects in the bottom of the tank, blocking effective heat transfer. The heating elements or the burner in a gas fired water heater has to work harder and longer, and water heating costs get higher every day!
WORST: A premature leaker.