The availability, distribution and control of freshwater resources have been at the centre of the human story since the start of the Neolithic revolution roughly 12,000 years ago. With the advent of the modern nation state and its attendant emphasis on sovereignty, self-sufficiency and rivalry, it comes as no surprise that interactions between states over shared watercourses have at times been tense and conflictual. This fact was elaborated by the Ex- UN Secretary General; Kofi Annan, Message during the World Water Day on 22nd March, 2002. He warned that… “Fierce national competition over water resources has prompted fears that water issues contain the seeds of violent conflict. By the year 2025 two thirds of the world’s population is likely to live in countries with moderate or severe water shortages as demand for water approaches the limit of the available supply”. Water as a fugitive resource, respects neither political boundaries nor commonly accepted notions of fairness or equity, hence posed the most complex management challenges to water managers of today. In the SADC region, shared waters cannot be viewed in a purely national context due to its fluidity and the mobility of its nature. It is factual that, over 70% of the water bodies in the region are transboundary in nature. In terms of state practice, the concept of community of interest is commonly traced back to a French decree of 1792 dealing with the opening of the Scheldt River to Navigation. The position expressed in this decree was quickly adopted in a number of instruments concerned primarily with rights of navigation in international rivers, but also in some early agreements not restricted to navigational uses. Therefore, the lakes, and watercourses which form the frontier between the two states or which are situated at the territory of both or which flow into the said lakes and watercourses shall continue to be considered as “common’. In this regard one may wish to refer to the recent global instruments namely; the UN Convention on the Law of the Non-Navigational uses of International Water (1997) which came into force on 17th August 2014 and the Convention on the Protection and Uses of Transboundary Watercourses and International Lakes (1992) which came into force on 6th October, 1996 and further in 2016 became an official global legal framework for transboundary water cooperation. These instruments are regarded as a vital step in building a strong foundation for global principles on water management and governance. Legal agreements between states during the colonial era as well as post-independence in the Southern Africa region, have formed the bedrock of cooperative water resources management regionally. The Anglo Germany Treaty of July, 1890 (The Helgoland Treaty), had established an agreement between the colonial powers of Great Britain, France, Portugal, Belgium and Germany and their respective spheres of influence over the African nations aimed to establish borders between the nations. Interesting to note in the presence of scarcity of geo-information over the areas in question; the water bodies (Rivers and Lakes) were used to mark the lines of influence hence boundaries of the sovereign states of today. This chapter therefore, will provide an account of the influence of the 1890 Anglo – Germany Treaty (Helgoland Treaty) and international customary law in regard to conflict resolution and transboundary water cooperation in the Southern Africa Region (SADC). It will also examine some of available information as well as the historical background of boundary treaties; legal frameworks for cooperation; importance of Africa Union(AU) resolutions on the same, such as Resolution AHG/Res16(1) of July 1964 as well as resolution CM/Res.1069(XLIV) of 1986 and finally a conclusion.