an apparatus for performing peritoneal dialysis includes a housing ; a peritoneal dialysis supply bag supported by and / or located above the housing ; a first valve for controlling gravity flow of fresh peritoneal dialysis fluid from the supply bag to a patient ; a second valve for controlling gravity flow of used peritoneal dialysis fluid from the patient to a drain ; and a pressure sensor positioned and arranged with respect to the gravity flow of fresh peritoneal dialysis fluid or the gravity flow of used peritoneal dialysis fluid to provide a reading used to evaluate a head height pressure .