The study was carried out to assess the efficacy of solar radiation as a disinfection method for well waters in some communities in the south east local government area of Ibadan metropolis, Nigeria. Well water sampling and quality tests were done during the dry season and parameters such as total solids, suspended solids, total hardness and coli form count were determined using various laboratory methods. Solar disinfection techniques were used and parameters such as volume of water, hours of exposure, colour of container and turbidity were considered. Data collected were analyzed using statistical packages, results are expressed in percentages, frequencies and representation. A 100% coli form count reduction was achieved for 4 and 5 L water samples in 7 L container. 7 h and above of exposure to sunlight were found to be ideal in reducing the coli form count. The degree of disinfection was relatively higher with white (97.9%) and black (98.4%) containers as compared to brown (95%) and blue (82%) containers. With increasing turbidity, solar radiation efficacy decreases. The experiments were found to provide satisfactory and viable performance compared to WHO drinking water standard with MPN count to be 7.2 per 100 ml for 7 h of exposure and 1.4 per 100 ml 8 h of exposure compared to 2478 per 100 ml before the solar disinfection exercise.

Key words: Well waters, solar radiation, disinfection, Ibadan.