Chemical Sampling and Analysis of ISS Potable Water: Expeditions 1-3

The early International Space Station (ISS) drinking water supply primarily consists of water recovered from humidity condensate and water transferred from Shuttle. The water is dispensed both from the stored water dispensing system (SVO-ZV) and the galley, which is an integral part of the condensate recovery system. The galley provides both hot and tepid water. An assessment of the quality of each potable water source is underway and consists of periodic collection of samples into Teflon^® bags for return to Earth via Shuttle. Water sampling hardware and procedures developed and used during the Shuttle-Mir program are employed on ISS without significant changes. This report provides results from detailed chemical analyses of recovered potable water and supplied (stored) water samples returned from ISS Expeditions 1 through 3. These results have been used to monitor the potability of the product and stored drinking water by comparing the results against water quality standards. The results are also used to evaluate the efficiency of the ISS water recycling systems. In general, the regenerated drinking water has met requirements although the lead levels are a concern. Stored (SVO-ZV) water quality has been acceptable except for cadmium and turbidity excursions.