Water quality criteria are all physicochemical and biological indicators that characterize a body of water. The current study aims at investigating the quality of two natural waters in the Gorj County sub-mountainous area (�u�i�a, Vaidei and Runc, capture Runc) used as drinking water sources of Targu-Jiu. Sampling and determinations use spectrophotometric, gravimetric, volumetric or electrometric techniques in accordance with standard methods (SR ISO and / or SR EN) for a series of physicochemical indicators analyzed between January - December 2017: thermal and acidification, oxygen regime, nutrients, salinity, relevant pollutants. Experimental values, annual averages related to the quality standards for potable water, ecological status and classification of water bodies, place the water of the two rivers in the drinking water category A1 and the first class of ecological quality. The Water Quality Index (WQI) for 9 selected parameters highlighted a sensitively close overall level of the water of the two rivers Susita (88) and Runc (85.2), the good quality category (7o-9o), reported to national quality standards for surface water which can be used for delivery as drinking water.The study of indicators of the two rivers in relation to national rules aligned with the European water requirements and research shows a high qualitative status corresponding to community uses.