The answer to 'why is my shower rusty water' is that it is likely due to corrosion or rust buildup in your plumbing system. This can happen when the water supply contains high levels of minerals, especially iron, which can cause discoloration and a metallic taste in the water. Rusty water can also be a sign of an underlying issue with your pipes, such as a leak or damage.
Some common causes of rusty shower water include old galvanized steel pipes, corroded copper pipes, or a malfunctioning water heater. Over time, these components can deteriorate and release rust particles into the water supply. This can lead to staining, clogged showerheads, and even health concerns if the water is consumed.