The answer to 'faucet rusty water' is that rusty water from a faucet is typically caused by corroded or rusting pipes or plumbing fixtures. This can happen due to age, mineral buildup, or chemical reactions in the water supply. Symptoms include reddish, brownish, or discolored water coming from the faucet.
The solution may be as simple as cleaning or replacing the faucet aerator or cartridge, but in some cases it could require replacing corroded pipes or plumbing components. If the issue is limited to one faucet, you may be able to fix it yourself, but if the problem is throughout your home's plumbing, it's best to call a professional plumber to diagnose and resolve the issue.