ABSTRACT: Assessment of the impact of tectonic faults on Central-Slovakian Volcanic Field hydraulic properties was studied using data from 529 hydrodynamically tested boreholes. This information was taken from the Slovakian hydrogeological wells and boreholes database (Geofond archive of the State Geological Institute of Dionýz Štúr). Changes in standard specific capacity 1q show that faults are not the most significant factors controlling volcanic formation hydraulic properties at the regional level. There is almost regular increase and decrease in standard specific capacity values in a gradual 200 m surplus buffer zone to a maximum evaluated distance 3 km from the faults. The significant impact of faults is evident in those with north–south orientation where there are higher mean standard specific capacities (1q) compared to others. We consider the low but also higher permeability of these tectonically unaffected Neogene volcanic formations is mainly due to the primary hydraulic properties of these formations which are strongly anisotropic. Permeability is locally increased only in some places; especially in the N-S oriented hydraulically active fault zones.