The interactions of water with H-ZSM-5, Cu-ZSM-5, and Co-ZSM-5 have been investigated by density functional theory (DFT). Calculations were also performed to determine the thermodynamics of metal removal from the zeolite. For all three forms of ZSM-5, water adsorbs by direct interaction of the O atom with the cation and hydrogen bonding of one of the two Il atoms with an oxygen atom in the zeolite framework. The magnitude of the energy of adsorption of one H2O molecule decreases in the order Cu-ZSM-5 (Cu as Cu+) > Co-ZSM-5 (Co as Co2+(OH)(-)) > H-ZSM-5 > Cu-ZSM-5 (Cu as Cu2+(OH)(-)). Adsorption of a second H2O molecule occurs with a smaller binding energy, which decreases in the order Cu-ZSM-5 (Cu as Cu+) > Cu-ZSM-5 (Cu as Cu2+(OH)(-)) > Co-ZSM-5 (Co as Co2+(OH)(-)) > H-ZSM-5. At 800 K, demetalation to form a gaseous metal hydroxide species is unfavorable thermodynamically but will occur spontaneously if the final product is a metal oxide. Demetalation of Cu is projected to occur much more readily than demetalation of Co, in good agreement with experimental observation.