ABSTRACT: The utilisable groundwater occurs in Quaternary and Triassie formations. The most valuable source of potable water is the Triassie karst-fractured carbonate aquifer. High negative human impact and generally high groundwater vulnerability to pollution have caused a significant groundwater contamination in both aquifers. Locally high groundwater contamination observed in the Triassie aquifer (B - up to 82 mg/dm3, Sr - up to 16,3 mg/dm3, As - up to 2,57 mg/dm3, N03 - up to 159,95 mg/dm3, trichloroethene - up to 841 ug/dm3) is alarming. This critical situation resulted in cIosing many intakes. Groundwater is intensively monitored ( 124 monitoring sites, functioning in the framework of national - 7 sites, regional - 7 sites. and local monitoring networks - 110 sites) in this area. All these networks have their own programme (variable number of sites, sampling frequency, range of chemical analysis) and they should be co-ordinated. The complex interpretation of data from all existing monitoring networks is necessary for assessment of the real state of groundwater quality in considered district.