If your water smells bad, it’s a big warning sign. Something’s wrong with your water softener, household pipes, or even your main water source. You might smell rotten eggs from hydrogen sulfide, often from sulfur bacteria in the brine tank. Maybe it’s a musty smell, which points to resin fouling or biofilm. Or perhaps you’re getting a chlorine-like odor from regenerant carry-over. Each of these smells has its own cause and solution.