Freshwater on earth’s surface constitutes only the 2.5% of the whole; of which 2,5% only 1% is accessible for use. Understandably, lakes are amongst the most important freshwater resources that are on our planet. Considering that most of them have been working their formation for thousands even tens of thousands of years we understand the paramount importance behind their protection and sustainability. As per available literature lakes globally seem to be on a quality-deteriorating on-going state with almost half of the lakes in Europe, America and Asia being in Eutrophic state. In this paper the focal point will be the Lake of Kastoria that besides being a fresh water source is a driving factor of this small city’s economy but also is a determining factor in regards with the quality of life of the people that live in its close quarters. Using available literature and measurements provided by the Management Body of Protected Areas of Western Macedonia, an analysis and comparison and contrast of the data took place and valuable conclusions were drawn that aided in the proposition of suitable recommendations in the scope of securing sustainability of the lake and the ensuring the passing on to the next generations.