The answer to 'water heater rusty water' is that rusty water from a water heater is typically caused by corrosion inside the tank. Over time, the metal tank can rust, which can cause the water to take on a reddish-brown color and a metallic taste. This is a common problem with older water heaters.
Some common symptoms of a rusty water heater include discolored water, a metallic taste or smell, and sediment buildup in the tank. If you notice any of these issues, it's important to address the problem promptly to prevent further damage and ensure the safety of your water supply.