Fuel cells (38) have water passageways (67; 78, 85; 78a, 85a) that provide water through reactant gas flow field plates (74, 81) to cool the fuel cell. The water passageways may be vented to atmosphere (99), by a porous plug (69), or pumped (89, 146) with or without removing any water from the passageways. A condenser (59, 124) receives reactant air exhaust, may have a contiguous reservoir (64, 128), may be vertical, (a vehicle radiator, FIG. 2), may be horizontal, contiguous with the top of the fuel cell stack (37, FIG. 5), or below (124) the fuel cell stack (120). The passageways may be grooves (76, 77; 83, 84) or may comprise a plane of porous hydrophilic material (78a, 85a) contiguous with substantially the entire surface of one or both of the reactant gas flow field plates. Air flow in the condenser may be controlled by shutters (155). The condenser may be a heat exchanger (59a) having freeze-proof liquid flowing through a coil (161) thereof, the amount being controlled by a valve (166). A deionizer (175) may be used.