Gravity-independent water separation within the condensing heat exchangers onboard manned spacecraft is achieved by using hydrophilic fin surfaces that promote the wetting and wicking of the condensate on the fin. It is also important for the fin surfaces to be antimicrobial to prevent the bacteria growth that may thrive in the moist environment of the fin surface. For practical and economical reasons, the coating must also be durable under wet conditions. Ag-exchanged zeolite A (Ag-ZA) coatings have been shown to have excellent hydrophilicity and are highly antimicrobial. In this study we show that Ag-ZA coatings are highly durable under wet conditions, maintaining their hydrophilic and antimicrobial properties even after submersion in water for 8 weeks. The durability of the hydrophilic and antimicrobial properties of Ag-ZA coating make it a preeminent candidate for use in condensing heat exchangers onboard manned spacecraft. (c) 2005 American Institute of Chemical Engineers.