Water management on ISS is responsible for the provision of water to the crew for drinking water , food preparation , and hygiene , to the Oxygen Generation System ( OGS ) for oxygen production via electrolysis , to the Waste & Hygiene Compartment ( WHC ) for flush water , and for experiments on ISS . This paper summarizes water management activities on the ISS US Segment , and provides a status of the performance and issues related to the operation of the Water Processor Assembly ( WPA ) and Urine Processor Assembly ( UPA ) . This paper summarizes the on - orbit status as of June 2012 , and describes the technical challenges encountered and lessons learned over the past year .