ABSTRACT: This contribution explores the problems posed by land subsidence on geohydrodynamic ground and surface water systems. This is particularly relevant to possible effects on water quality and quantity pumped for public and commercial supply and in ensuring water source protection zone requirements. Land subsidence determines the features of permanent and time-limited changes in hydrogeological structures, and it requires effective measures for harm-minimization; including classification of protected sources, delineation of water resource protection zones and monitoring effectiveness of current measures. Case study examples from the Czech part of the Upper Silesian Basin – Doubrava-Špluchov and Darkov Spa catchment area are presented herein; with attention focused on problems encountered in delimitating protection zones in undermined areas.