摘要：This study was conducted to determine the quality of water stored exteriorly in storage tanks. The water samples were obtained from ten different storage tanks at homes in Tanke area, Ilorin. The water samples were investigated for their physicochemical and bacteriological characteristics. The pH, suspended solids, chloride and total hardness were determined using pH meter, loss in weight on drying, argentiometric and complexometric titration, respectively. The viable bacterial, total coliform and faecal coliform counts were determined by standard plate count method, multiple tube fermentation and the use of differential media, respectively. The viable bacterial count ranged from 2.1x101 to 1.6x103 cfu mL-1. The total coliform and faecal coliform ranged from 0 to 210 cfu 100 mL-1 and 0 to 6 cfu mL-1, respectively. The pH of the water samples ranged between 6.53 and 7.45; the suspended solids between 0.5 and 6 mg mL-1, the total hardness between 10 and 55 mg L-1 and the residual chlorine contents ranged 0.23 and 0.89 mg L-1. A total of ten bacteria were isolated from the stored water sample collected. The bacterial isolates were: Bacillus lentus, Bacillus licheniformis , Bacillus circulans, Staphylococcus aureus , Lactobacillus brevis, Streptococcus sp ., Corynebacterium kutscheri, Micrococcus varians, Pseudomonas aeruginosa and Escherichia coli . This study revealed that the quality of water in a storage tank depends on the source from which it was drawn and the handling of the tank by the users. Recommendations were made that good quality water from borehole or municipal supply should be stored in the storage tank and the users should ensure proper sanitation in order to minimize the rate of contaminations.
