A Rechargeable Water Softener should be an out-and-out requirement for every commercial espresso machine... Why? Water softeners reduce the calcium or magnesium ion concentration in hard water.
Calcium and magnesium carbonates tend to precipitate out as adherent solids on the surfaces of pipes and especially on espresso machine heat exchanger surfaces of boilers. The resulting scale buildup can restrict water flow. In boilers, the deposits act as thermal insulation that impedes the flow of heat into the water; this not only reduces heating efficiency, but allows the metal to overheat which, in a pressurized system, can lead to catastrophic failure.
Whether you area has hard water or not, it is a good idea to purchase and install a water softener to prevent calcium and lime deposits from accumulating in your espresso machine.
This rechargeable water softener is one of your best options. Because it is rechargeable no filter cartridge replacement is necessary. Recharging is a snap and is done with rock salt found at any hardware, plumbing or even grocery and drug stores.