This study was carried out to investigate the effectiveness of Ultraviolet light for waste water disinfection. Recent studies have shown that water chlorination causes several environmental problems and therefore the need for safer methods. Ultraviolet light is currently a more preferable method for water disinfection. It has some inherent advantages over all other disinfection methods which are: no chemical consumption, no transportation and handling, no harmful by-products formed, a minimum of, or no, moving parts therefore high reliability and low energy requirements. Three critical points of water quality were focused on incoming and outgoing points of the fish culture tank and outlet of the filter tank. The outlet is important because it indicates the effectiveness of Ultraviolet light, specifically the ability to disinfect the water so that pathogenic bacteria are killed after the water has been treated with Ultraviolet rays. Waste water from the sampling points were analysed for different parameters. Temperature was determined using Mercury in glass thermometer (British standard BS593). pH was determined using a Hanna pH meter model No. 02895, CaCO3, NO3, NO2 and NH3 were determined using water analysis kit by Hague while the microbial analysis was carried out using the MacConkey agar plate. The UV disinfection method was found suitable for treatment of waste water. This is obvious since the treated sample of water had lower coliform count than the other waste water samples. The favourable quality of the UV disinfected water was also observed in its improved chemical properties especially ammonia and dissolved oxygen.