ABSTRACT: The gravel pits are an inseparable part of Bratislava. They arrise as a reason of mining of big amount of gravel materials. Mining holes were filled up by groundwater. In present they serve for rest, recreation and fishing. Gravel pits Rusovce, Draždiak, Kuchajda, Zlaté piesky and Vajnory are in present time allowed swimming pools. Water quality of natural swimming pools and river Danube from hydrogeochemical and microbiological aspects was revalued in base of Government Decree Nr. 296/2005.