In-Line Ultraviolet Water Disinfection System produces water that is free from disease causing micro-organisms, without the use of chemicals. The Water Disinfection System functions on ultraviolet light that is a natural, cost effective and environmentally friendly source of disinfection process for use in recreational facilities, homes and other areas where safe. The Ultraviolet Water Disinfection System destroys infectious microbes by directing light to their reproductive mechanism. The In-Line Ultraviolet Water Disinfection System also eliminates the risk of disease.