The Helsinki Rules on the Uses of the Waters of International Rivers is an international guideline regulating how rivers and their connected groundwaters that cross national boundaries may be used, adopted by the International Law Association (ILA) in Helsinki, Finland in August 1966. In spite of its adoption by the ILA, there is no mechanism in place that enforces the rules. Notwithstanding the guideline's lack of formal status, its work on rules governing international rivers was pioneering. It led to the creation of the United Nations' Convention on the Law of Non-Navigational Uses of International Watercourses. In 2004, it was superseded by the Berlin Rules on Water Resources.