Why is my hot water brown?

Brown or rusty hot water usually indicates corrosion inside the tank or a failing sacrificial anode. Sediment build-up at the bottom of the cylinder can also discolour the water and reduce efficiency.

If only the hot water is discoloured, have the system inspected promptly — replacing the anode early can extend the tank's life, but ongoing rust often signals the tank is near the end of its life.