There are several options for hard water treatment in your home. These options include:
Whole house/point-of-entry (POE) systems treat all or most of the water entering your home. They are installed at the source of the water entering your residence. A water softener, also called a water softener system, is an example of a POE system. The Water Quality Association lists these options as POE systems: (see the benefits of using a whole house water softener)
Point-of-use (POU) systems typically treat water at the point of consumption, such as at the kitchen sink. Some work in line with the plumbing while others will dispense filtered water through a separate faucet. A filtered water pitcher is an example of a POU system. The Water Quality Association lists these options as POU systems:
Salt Free systems do not technically soften your water. Water softening is the process of removing hardness (Calcium and Magnesium), while saltless systems do not remove hardness from your water. A salt-free system changes the composition of the minerals so they will not adhere to your plumbing. These are anti-scaling, descalers, or scale inhibitors while a water softener removes hardness.