The answer to 'sump pump rusty water' is that a sump pump with rusty water is often caused by corrosion within the pump itself or the discharge pipe. This can lead to the pump's internal components deteriorating and the water becoming discolored. Symptoms include reddish or brownish water being pumped out, unusual noises from the pump, and reduced pumping efficiency.
The solution may be as simple as replacing the pump's impeller or other internal parts. However, if the pump housing or discharge pipe is severely corroded, the entire sump pump system may need to be replaced. In many cases, it's best to call a professional plumber to diagnose and fix the issue, as they can ensure the problem is properly addressed and the sump pump is functioning safely and effectively.