Context: Water is an important resource for hospitals. There are few studies about the quality, quantity and cost of water that is required for health care. Aims: To study the quality, quantity, cost and applications of water in a hospital. Settings and Design: Observational study. The study was done in a cancer hospital in eastern India. Methods and Material: Water generation and consumption patterns and costing were assessed after: Discussion with the engineers; analysis of documented records; observation of patient/visitor/staff behaviours; measurement of flow rates and metered readings; Individual water consumption surveys. Statistical Analysis Used: None. Results: The total filtered reverse osmosis (RO) water used by the hospital per day was 200,000 L. This equated to 1093 L/patient/day. The volume of filtered reversed osmosis water consumed showed that the total water usage for drinking was 1%, water usage for hand-washing was 18%, water usage for showering was 6%, kitchen water consumption was 2%, housekeeping activities usage was 4%, central sterile supply department usage was 4%, heating, ventilation, and air conditioning systems usage was 36%, hot water consumption was 5% and toilet flush usage was 24%. Cost was Rs. 1119/- for 10,000 liters of RO water and about Rs. 31/- for 10,000 liters of raw water. Conclusions: The economics of hospital water both in terms of consumption and cost is a valuable source of information for hospital planners, administrators and hospital engineers. Key Messages: • Water is a precious resource. Wastage needs to be minimized • It is important for hospitals to monitor its water usage • Safe and adequate water is essential for effective hospital infection control and monitoring its microbiological quality is of paramount importance