The answer to 'my water softener smells bad' is that a smelly water softener is often caused by bacterial growth or mineral buildup. This can happen when the softener isn't properly maintained or if there's an issue with the brine tank or resin beads.
Some common symptoms of a smelly water softener include a rotten egg or musty odor coming from the taps, discolored or slimy resin beads, and decreased water softening performance. To fix the problem, you'll need to clean and sanitize the softener, replace the resin, or address any underlying issues with the system.