Yes, potassium chloride is an acceptable substitute for salt in most salt-based ion-exchange water softeners. Although the use of potassium chloride will reduce the amount of sodium in the softened water, states that legislate against water softeners on the basis of salt contamination also view potassium chloride as a form of salt. In addition, potassium chloride is substantially more expensive than standard salt, so one must be sure to evaluate all options before deciding on the use of potassium chloride. If a member of your household is on a low sodium diet for health purposes, it is advisable to consult a medical practitioner about the use of either sodium or potassium-based water softener. In areas of moderately hard water, a salt-free water conditioner may be a viable alternative.