Scale buildup — Minerals in hard water deposit on the heating element over time, reducing efficiency and causing discolored water.
Tank corrosion — Aging tank lining may rust, releasing brown/orange particles into the water.
Anode rod depleted — The sacrificial anode rod wears out after 1–2 years, no longer protecting the tank from corrosion.
Stagnant water — Infrequent use allows sediment to accumulate at the tank bottom.