Recreational use of inland and marine waters is increasing in many countries. It is estimated that foreign and local tourists together spend many days annually at coastal recreational resorts. Swimming is considered to be a healthy leisure activity for both the young and old. Swimming is even advised as the most appropriate sport for asthmatic children, mainly on the grounds that inhaling moist air is less conducive to triggering exercise-induced asthma. Swimming pools may be supplied with fresh, marine or thermal water. Swimming pools may be located indoors, outdoors or both; they may be heated or unheated. Swimming pools can be categorized as public, semi-public, and residential pools. A quality of swimming water takes into account physical, chemical and microbiological quality information and shall be maintained these water quality standards at all times. Pool water clarity must be maintained in a clean, clear condition so that a 150 mm diameter matt contrasts with the color of the bottom of the swimming pool, is clearly visible when viewed through the pool water at the deepest part of the swimming pool. There must have a minimum chemical criterion by which a swimming pool should be operated to minimize health risks to bathers to acceptable levels. The microbiological quality of water must not present risk to the health of bathers. A variety of microorganisms can be found in swimming pools, which may be introduced in the pool water in a number of ways. In many cases, the risk of illness or infection has been linked to fecal contamination of the water, due to feces released by bathers or contaminated source water or, in outdoor pools, may be the result of direct animal contamination. If swimming pool is not managed properly, bathers acquire bacterial, viral, parasitological and fungal infection. To minimize/avoid these risks of infection a variety of disinfection techniques are used. Disinfection methods include filtration to remove pollutants, disinfection to kil