Looking to soften your water a bit without completely removing the mineral content? Try out one of these in-take resin water softeners. Not only are they rechargeable, so they’ll last basically forever, but they easily fit on any machine that uses an intake tube to pull water from the reservoir into the machine — such as the Rancilio Silvia, any of the Quick Mill machines or the Saeco Aroma.
It’s not super sophisticated, but it will reduce the hardness of your water and, in turn, how fast it takes scale to build up in your boiler and related waterworks. You can recharge it by putting it in a glass with water with a few tablespoons of non-iodized and additive-free salt (like kosher) and let it hang out once a week.