Non-equilibrium molecular dynamics (NEMD) simulations of liquid water have been performed at 298 K in external square-wave electric fields. Significant non-thermal field effects were noted for coupling of rotational and translational motion with marked increases in diffusion. Non-linear field effects were evident above around 0.05 V angstrom(-1), with enhancements in translational and rotational motion. Translational and librational modes orthogonal to the field's direction were promoted in higher- and lower-frequency fields, respectively, owing to respective coupling of field periods with dipolar and hydrogen bonding relaxation timescales and promotion of libration about a more 'stationary' dipolar alignment for more sustained periods. (C) 2013 Elsevier B.V. All rights reserved.