Stop many espresso machine problems at the source with Best Water Technology in-tank water filters and softeners. Hard water can cause scale to build up on the inside of your boiler which will eventually impact the performance of your espresso machine. In-tank water filters are meant for espresso machines that are not directly plumbed in to a water source. If you want to directly plumb in your espresso machine to a water source then check out our inline water filtration system.