Turbidity is a measure of water cloudiness caused by suspended particles like silt, clay, algae, and organic matter. High turbidity indicates water quality concerns—particles may harbour bacteria, interfere with disinfection, and affect taste and appearance. Drinking water standards set maximum turbidity levels, with treatment processes including settling, filtration, and coagulation to reduce turbidity. Source water turbidity varies with weather, runoff, and watershed conditions. Water utilities monitor turbidity continuously as a key quality indicator. Turbidity also affects aquatic ecosystems by reducing light penetration and potentially harming fish and other organisms. Environmental regulations may address turbidity in stormwater discharges and construction site runoff. Low turbidity is essential for safe, aesthetically acceptable drinking water.