The answer to 'why is my water softener foul smell' is that a foul odor coming from your water softener is often caused by bacterial growth or mineral buildup. This can happen when the softener isn't maintained properly or if there's an issue with the brine tank.
Some common symptoms of a foul-smelling water softener include a rotten egg or sewage-like odor coming from your taps, slimy buildup in the brine tank, and decreased water softening performance. The solution typically involves cleaning and disinfecting the softener, replacing the resin, or addressing any underlying issues with the system.