Water, essential for health, turns harmful when contaminated, causing diseases like diarrhea and cholera. WHO reports 5,05,000 diarrheal deaths yearly due to microbiologically contaminated water. E. coli infections from water contamination lead to severe digestive issues, sometimes requiring hospitalization. Parasites in water trigger chronic diarrhea, vomiting, and nutrient absorption problems. Chemical contaminants disrupt digestion and may cause long-term damage. It is thus important to protect water by regular testing, sanitation improvement, and water purification methods.