Water pollution is one of the biggest environmental challenges facing humanity, and using microorganisms in water treatment is considered an effective and sustainable solution. Bacteria and fungi break down organic matter and harmful chemical compounds, such as heavy metals, oils, and pesticides, converting them into less harmful substances, significantly improving water quality. This technique is applied in wastewater treatment plants and industrial water treatment facilities, providing an environmentally safe alternative to traditional chemical methods, which may leave harmful side effects. It can also be used in remote or resource-limited areas, reducing the need for expensive infrastructure and offering sustainable solutions. Furthermore, the use of microorganisms in water treatment enhances public health by reducing the spread of waterborne diseases such as diarrhea, typhoid, and cholera. It also helps maintain ecological balance and improves soil and groundwater quality when treated water is reused for irrigation and agriculture.