Why does my water smell like rotten eggs? A lot of times when that happens, it's usually from a well. And if it's from a well, it can even be a public well in a city that you live in, it's sulfur. And it's a bacteria. And it can be remedied by softening your water. You have to soften the water first before it goes into the water heater. Because as the water heater heats, is releases the sulfur and the bacteria, and that's why it starts to smell like rotten eggs. So if you take the sulfur bacteria out of the water first, that smell should go away. If it persists, you have to flush your tank and/or replace your tank to get rid of that smell. But it is a very disturbing smell.