A rapidly deteriorating supply of healthy freshwater resources, exacerbated by climate change, intensifies social and economic injustices and inequalities across the world. Strong public laws and institutions upholding equitable procedures for public participation, access to justice and information regarding the fair distribution of access to sufficient water resources are needed more than ever to protect the most vulnerable. International water law and river basin treaties have poor provisions for public participation. This chapter demonstrates how the UNECE environmental regime, especially through the Aarhus Convention and Protocol on Water and Health, provides a comprehensive framework for the principle of public participation, access to justice and information, including identifying where it fills gaps in international water law and basin treaties. For example, non-state actors including the public and non-governmental organisations (NGOs) have limited almost non-existent rights under the 1997 UN Watercourses Convention beyond the procedure on non-discriminatory access to justice. In contrast, the public including NGOs are given a significant participatory role in law making, implementation and enforcement in the UNECE water regime. This contributes to procedural justice and the principle of intra-generational equity in international water law. The Water Convention, however, should be amended to provide for all three pillars of public participation.