Vlasina Lake lies on a plateau surrounded by the mountains of Vardenik, Čemernik and Gramada or the Crkvena mountain (Plana, as the locals call it) in southeast Serbia. It is composed of crystalline schists belonging to the first group and the Rhodope system. Below Vrtop (1,721m), the highest peak, is the source of the Vlasina, at 1,500m, far away from roads, large settlements and industry. At the foot, in the village of Preslap at an altitude of 1,100m, there is a bottling water facility which has a 3,000m long pipeline from the source to the facility.
Vlasina spring water, bottled without any processing, is of the same quality as the source, while the quality and content of the soil provides the finest water filtration which ranks it among the cleanest waters. An exceptional softness, a neutral pH value and a very low content of nitrate, sodium and other minerals classify it into a group of very low mineralized waters with only 30-40 mg/l of dry residue at 180°C.
The water temperature at the source is 6°C throughout the year.