The complex [Ru(Mebimpy)(bpy)(OH2)](2+) [Mebimpy = 2,6-bis(1-methylbenzimidazol-2-yl)pyridine; bpy = 2,2'-bipyridine] and its 4,4'-(PO3H2CH2)(2)bpy derivative on oxide electrodes are water oxidation catalysts in propylene carbonate and 2,2,2-trifluoroethanol (TFE) to which water has been added as a limiting reagent. The rate of water oxidation is greatly enhanced relative to that with water as the solvent and occurs by a pathway that is first-order in H2O; an additional pathway that is first-order in acetate appears when TFE is used as the solvent.