The answer to 'garbage disposal rusty water' is that a rusty garbage disposal is often caused by corrosion over time. This can lead to discolored, rusty-looking water coming from the disposal. Common causes include mineral buildup, acidic foods, and age of the unit.
Some solutions include cleaning the disposal with vinegar or lemon to remove buildup, or replacing the disposal if it's very old and heavily corroded. However, if the problem persists or you're unsure of the cause, it's best to call a professional plumber to diagnose and fix the issue.