The answer to 'supply line making noise' is that a noisy supply line is often caused by water pressure issues, mineral buildup, or loose connections. The most common symptoms are a whistling, banging, or vibrating sound coming from the pipes. Solutions can include adjusting the water pressure, cleaning the line, or tightening fittings.
If the noise is intermittent or limited to one fixture, it's likely a DIY-friendly issue that you can troubleshoot and fix yourself. However, if the noise is constant or affects multiple fixtures, it could indicate a more serious problem with the plumbing system that requires a professional plumber to diagnose and repair.