Armed conflicts have an impact on freshwater resources and often damage water installations, which could be targeted or incidentally damaged, affecting water quality and quantity and limiting access for the civilian population. Thus, in situations of armed conflict, protecting freshwater resources and related installations becomes essential. International humanitarian law (IHL) and international environmental law (IEL) provide for relevant rules that limit the impact of armed conflicts on freshwater and water infrastructure. IHL protects civilian objects, objects indispensable to the survival of the civilian population, works and installations containing dangerous forces and the natural environment. It also prohibits employing poison or poisonous weapons and environmental modification techniques. IEL regulates the sustainable and environmentally sound use, development and management of water resources. Progress in the realm of the human right to water and the rise of environmental consciousness further necessitate an eco-friendly approach that recognizes comprehensive protection. Therefore, this article examines the interplay between IEL and IHL, explaining how IEL can contribute to the interpretation of IHL rules and exploring areas where IEL could complement IHL rules relevant to the protection of freshwater resources and related installations during warfare.