You turn on the hot tap and out comes tea-colored water. Before you panic about the plumbing, run one test — it takes thirty seconds and tells you almost everything.
The hot-only test
Run the cold tap for a minute: clear? Now run the hot: rusty? If only the hot water is discolored, the corrosion is in the water heater or the hot-water piping — not the supply. If both run rusty, it is the supply or the main piping, a different problem entirely.
If it is the tank
Rusty hot water with clear cold points at the tank interior corroding — usually a depleted anode rod that stopped protecting the steel years ago. This is the same corrosion pathway that ends in pinhole leaks and tank failure. Other traveling companions: metallic taste or smell, and water that starts clear then turns rusty as the tank drains down.
If it is the pipes
Galvanized steel hot-water piping corrodes from the inside and sheds rust into the flow. Clues: the whole house’s hot water is affected equally, the heater is relatively new, or the discoloration is worst at fixtures farthest from the heater. A technician can usually distinguish tank rust from pipe rust by sampling at the heater’s drain valve.
What to do next
Do not just live with it — rust in hot water means active corrosion somewhere, and active corrosion eventually leaks. If the heater is the source, the next steps are an anode-rod inspection and an honest assessment of the tank’s remaining life. If it is the piping, that is a repipe conversation. Either way, start with a diagnosis: call (833) 713-2101 and mention the hot-only test result.