Solar Water Disinfection, or SODIS, is a simple, low-tech method of purifying drinking water using sunlight. The process involves filling transparent plastic or glass bottles with contaminated water and placing them under direct sunlight for 6-48 hours, depending on weather conditions.
UV-A radiation and thermal heating deactivate pathogens such as bacteria, viruses, and protozoa, making the water safe for consumption. SODIS is widely promoted for its affordability, accessibility, and minimal infrastructure needs, especially in disaster zones, refugee camps, and low-income rural or peri-urban communities.
It is recognized by theWorld Health Organization as an effective household water treatment option and contributes directly to improved health, reduced waterborne disease, and increased water access for vulnerable populations.