The answer to 'bathtub rusty water' is that it is typically caused by corrosion in the plumbing system or sediment buildup in the water heater. Symptoms include reddish-brown water coming from the bathtub faucet, staining of the bathtub, and a metallic taste or odor in the water. Solutions can range from simple DIY fixes to more complex professional repairs, depending on the underlying cause.
If the rusty water is isolated to the bathtub, it may be due to a corroded drain pipe or fixture. This can often be addressed by homeowners through cleaning, replacing washers, or even replacing the faucet. However, if the issue is throughout the home's plumbing, it likely indicates a more systemic problem that requires the expertise of a professional plumber to diagnose and resolve.