- WikiProject Rivers is a WikiProject which aims primarily to describe the Earth's rivers in a consistent and complete fashion. The parent of this WikiProject is the WikiProject Geography.
- WikiProject Water provides information on water purification.
- WikiProject Sanitation provides information on all issues surrounding sanitation, including wastewater management.
- WikiProject Lakes describes the Earth's lakes. The project aims to consolidate and unify pages relating to lakes around the world.
- WikiProject Dams is a WikiProject formed to organize and improve articles related to dams.