The best way to soften water in household water systems is to use a water softener unit connected into the water supply line. You may want to consider installing a separate faucet for unsoftened water for drinking and cooking. Water softening units also remove iron. The most common way to soften household water is to use a cation-exchange water softener. Softeners may also be safely used to remove up to about 5 milligrams per liter of dissolved iron if the water softener is rated for that amount of iron removal.
Softeners are automatic, semi-automatic, or manual.
Each type is available in several sizes and is rated on the amount of hardness it can remove before regeneration is necessary. When the resin is filled to capacity, it must be recharged. Fully automatic softeners regenerate on a preset schedule and return to service automatically. Semi-automatic softeners have automatic controls for everything except for the start of regeneration. Manual units require manual operation of one or more valves to control backwashing, brining and rinsing.