Salt-free systems are not true water softeners. These systems are often called “water conditioners” or “descalers.”
Salt-free systems can help reduce the buildup of limescale, the chalky substance you see in dried hard water spots, as well as other chemicals. Water conditioning systems work by altering the chemical structure of water minerals through the descaling process, which prevents solids from depositing in pipes and water-using fixtures.
Water softener salt removes minerals, including calcium and magnesium — which cause hard water — through a process called ionic exchange and replaces them with soft minerals potassium and sodium.
Is a salt-free conditioner the way to go?
One concern with no-salt systems is they’re not as effective in places where water sits, like in your water heater. Those areas can still get a buildup of limescale.
Some nice things about salt-free systems are they cost less to operate and don’t require much maintenance.
Conditioned water also doesn’t have the “slippery” feel you get from a water softener, which can be an advantage or disadvantage, depending on your preference.
The operation of water conditioners can also be affected by the types of contaminants you have in your water which can vary by region.