A method and a system comprising an integrated water purifying apparatus with a pre-filter circuit including a particle filter and an activated carbon filter arranged to produce pre-treated water; a fluid circuit arranged to receive pre-treated water from the pre-filter circuit, the fluid circuit including an RO-pump and a Reverse Osmosis (RO) device arranged to produce purified water; a heating device arranged to heat purified water from the RO device to a temperature above 65°0 C.; the water purifying apparatus further arranged to heat disinfect the fluid circuit using the heated purified water. The system further comprises a line set connected to the purified water outlet connector at a water line connector of the line set, wherein the line set includes at least one sterile sterilizing grade filter arranged to further filter the purified water.