Sulfur smell is almost always bacteria doing their thing. They munch on organic matter in your drain, water heater, or even your well water. The waste they burp out? That’s hydrogen sulfide gas—the exact same stuff that makes hot springs smell so… memorable. Think of it as microscopic dragons living in your pipes, breathing fire. Cute, but stinky.
If the smell comes from your tap, it’s probably in your water supply. Well water is a common culprit, but even city water can pick up sulfur from old pipes. If it’s just the sink drain, though? You’ve got a biofilm party happening. Time to crash it.