Hydrogeological documetation in the terms of deposit exploitation, water injection to the rock formations, drainage, and other mining activity requires the characteristic of groundwater conditions, mainly in the field of groundwater hazards. Hydrogeological documentations are the basis for granting or renewing a concession. The necessity of a general description in hydrogeological documentation as a result of legal regulations is justified and understood, although broader and non-standard scope should be revised, connected with: development of research methods in hydrogeology, scope of their applicability, modern research methodology for measurement and evaluation of hydrogeological parameters, new mining techniques. Commonly realized documents include, among other things, characteristics of hydrogeological conditions, in particular the extent of geological structure planned for water injection, depth, thickness and capacity of reservoirs, hydrogeological parameters, groundwater flow directions, isolation conditions and hydrogeological parameters of rock formations directly above reservoirs. Based on the documented work, the paper describes the problem of presenting the most important hydrogeological aspects that determine the possibility of water injection into the rock formations, the scope of hydrogeological investigations and justification of the observation and measurement conducted for the assessment of environmental hazards caused by water injection.