The answer to 'pressure regulator rusty water' is that a rusty pressure regulator is a common plumbing issue that can lead to discolored, rust-colored water. This is typically caused by the regulator itself corroding over time, allowing rust and sediment to enter the water supply. Symptoms include reddish, brownish, or orange-tinted water coming from taps and fixtures.
In most cases, the solution is to replace the pressure regulator. This is generally a straightforward DIY project, but it's important to shut off the main water supply first and follow proper safety precautions. However, if the issue persists or you're uncomfortable doing the work yourself, it's best to call a professional plumber to diagnose and resolve the problem.