Fuel cells are devices capable of producing both energy and clean water. Here the concept of using hydrogen as a carrier of water and energy is explored by studying the quality of water produced by two modern commercial fuel cells, a 1 kW residential-scale polymer electrolyte membrane fuel cell (PEMFC) and a larger 300 kW molten carbonate fuel cell (MCFC). The results show that water produced by the PEMFC meets nearly all US Environmental Protection Agency (USEPA) and World Health Organization (WHO) drinking water requirements. Nickel and aluminum concentrations present in the MCFC water as well as pipe material corrosion products (nickel, aluminum and manganese) found in water from both systems are easily controlled. Without using any additional condensing system, it is possible to recover approximately 8% of the theoretical amount of water generated by the fuel cell. The amount of water produced by the PEMFC is sufficient to satisfy drinking water needs in a typical American household if a recovery efficiency of 40% is reached. Copyright (C) 2010, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.