First, do a simple sniff test. Run the cold water from your kitchen tap—does it stink right away? If yes, the problem is probably in your well or the main water supply. If the smell only hits you after the water sits for a minute, it’s likely bacteria partying in the pipes.
Now test the hot water. If only the hot side reeks, your water heater is the villain. It’s probably got a sulfate-eating bacteria colony throwing a rave inside the tank. Pro tip: if the smell is stronger when you’re running hot water, your heater needs a serious chat.
