Rusty or discoloured water
Run the hot tap into a white bucket. If the water comes out with a brown or orange tint and the cold runs clear, the inside of your tank is corroding.
Every storage tank has a sacrificial anode inside it, a metal rod that corrodes so the steel tank does not. Once the anode is gone, the tank itself starts going. Rust in the hot water usually means that process is already well underway.
Noise from the tank
Rumbling, popping or a kettle-like groan is sediment. Minerals settle at the bottom of the tank and the heating element cooks underneath the layer, which both wastes power and stresses the steel.
Caught early, a flush can buy years. Left long enough, the sediment layer will eventually crack the glass lining and the tank starts leaking.
Water that runs out faster than it used to
If the same shower that used to be comfortable now runs cold two minutes early, something has changed. On electric tanks it is usually a failed lower element, which means only the top half of your tank is heating.
That is a cheap repair on a healthy tank. It is not worth doing on a fifteen year old one that is about to leak anyway, which is why the age of the unit matters as much as the fault.
Moisture around the base
A little water from the relief valve line is normal, particularly on a hot day. Water pooling at the base of the tank is not.
A tank that is weeping from the body is finished. There is no repair for it, and the failure mode is that it eventually lets go all at once. If your unit sits inside the house or above living space, this is the sign to act on immediately.
What to do about it
Note the age. There is a manufacture date stamped on the compliance plate. Anything over ten years with any of the symptoms above is on borrowed time.
Get it looked at before it fails rather than after. A planned replacement is a normal booking at a normal price. A tank that fails on its own schedule costs you the replacement plus whatever the water damaged on the way out.
Written by the team at Adlington Plumbing. Licensed plumbing and gas fitting across Newcastle, Lake Macquarie and the Central Coast. Licence 384065C.