Johns Island is the one part of our service area where water treatment genuinely matters for a lot of households, because plenty of homes here are still on a private well.
If you are on a well
The usual complaints are orange staining in sinks and laundry, a smell like rotten eggs, or water that leaves a film. Those are iron, sulphur and hardness, and they each need different equipment. There is no single system that handles all of it, which is why a proper water test comes before any recommendation.
Testing is not optional here
Private wells are not treated or monitored by anyone but you. Alongside the things you can taste and see, it is worth testing for bacteria and nitrates, particularly if your well is older or shallow. We would far rather test first than sell you something that treats the wrong problem.
If you are on city water
Newer neighbourhoods along Maybank Highway are connected to the municipal supply, and the honest answer there is that most homes do not need much. A filter at the kitchen tap handles the chlorine taste, and that is usually enough.
Softening and filtering are not the same thing
Softening deals with hardness and the scale it leaves in your water heater and taps. Filtering deals with taste, smell, sediment and iron. Plenty of homes want one and not the other, and it is worth understanding which you are being quoted for.