Carbon tetrachloride (CCl4) contaminates the ground water in many waste sites. There is interest in using Fe(0) nanoparticles to accelerate degradation to less harmful products (e.g. formate over chloroform). In our previous work, we modeled the reaction of atomic Fe with CCl4 and found low-barrier pathways leading to thermodynamically stable organometallic complexes. Here we report on our investigation of the role of water molecules in the reaction, starting with the (Fe + H2O + CCl4) system. We used DFT and highly correlated theories to characterize stable structures and transition states along the pathways and to explore the interaction of these species. Our DFT calculations raised the prospect of a relatively low barrier (< 5 kcal/mol) to reaction of CCl4 with HFeOH. However, highly electron correlated calculations yielded a much higher barrier to reaction, consistent with the need to unpair d-electrons in forming an HFeClOH •CCl3 intermediate.