Wastewater contains many bacteria that cause many diseases. For example, one gram of body output (sweat, urine or feces) contains 10 million viruses and a million bacteria. For example, salmonella bacteria that lead to typhoid fever and gastroenteritis. Shigella bacteria cause diarrheal diseases, and Escherichia coli causes vomiting and diarrhea and may lead to dehydration, especially in children. Leptospira bacteria cause inflammatory liver, kidneys, and central nervous system diseases, while Vibrio bacteria cause cholera. These types of bacteria and others cause various diseases due to dealing with water contaminated with sewage, whether by drinking, bathing, or even eating fish caught from this water instead of staying near contaminated water bodies. It can be referred to diseases such as polio, yellow fever, scabies and malaria. Keywords: Bacteria, Disease, Environment, Microbial, contamination.