Abstract
The article analyzes the sources of international legal regulation of transboundary water resources, which are an international treaty, international custom and resolutions of international organizations (including judicial institutions) and decisions of non-governmental organizations. First of all, these are two universal multilateral treaties in this area: the 1997 UN Convention on the Law of the Non-Navigational Uses of International Watercourses and the 1992 UNECE Convention on the Protection and Use of Transboundary Watercourses and International Lakes, as well as a system of regional, local and bilateral international treaties. Despite the framework nature, the role of universal treaties is important as sources of international legal regulation of transboundary water resources, since, on their basis, states conclude international treaties in relation to a specific transboundary watercourse. In addition to the 1992 Helsinki Convention, the UNECE has developed three more environmental conventions that are of direct importance for the protection and conservation of transboundary waters, which, as sources of international legal regulation of transboundary water resources, create a framework international legal basis for cooperation in this area.