Evidence from a number of field sites suggests that water seepage through fractured unsaturated zones may proceed, in part, by means of fast preferential flow paths. This paper presents conceptual and numerical models which aim at developing an understanding of water seepage behavior in such media, and exploring conditions for fast preferential flow. Water seepage has been numerically simulated in heterogeneous fractures, which were conceptualized as two-dimensional heterogeneous porous media. Flow was found to proceed in dendritic patterns along preferential paths, giving rise to such features as localized pending and bypassing. Fast preferential flow can occur from 'external' (non-uniform boundary conditions) or 'internal' mechanisms (heterogeneities), or a combination thereof. A most effective condition for fast preferential flow is the presence of sub-horizontal barriers of significant length. Limited parameter variation studies have shown strong dependence of seepage patterns on fracture permeability and applied flow rate. The temporal evolution of seeps proceeds on a vast range of time scales. This casts doubt on the applicability of steady-state concepts for water migration in unsaturated zones of fractured rock where infiltration is episodic. An approximate invariance of seepage behavior was derived for simultaneous space-and-time scaling, suggesting that seepage patterns should appear more vertically elongated as the scale of observation is increased. Numerical simulation experiments have confirmed this invariance, as well as its limits of applicability.