Jerusalem Onyedikachukwu OB

Water meant for drinking and domestic use can easily become a source of infection if stored under poor sanitary conditions. This study emphasizes on the bacteriological analysis of water tanks in halls of residence in the University of Benin, Edo state Nigeria. Swab and water samples were taken aseptically from water tanks in the halls of residence and in a household with regularly treated water tanks. Serial dilution and pour plate methods were carried out for the isolation of microorganisms on different sterile media. The population of the bacteria isolates were enumerated using the colony counter. Pure cultures were obtained by the streak plate method and they were characterized by Gram staining and some biochemical tests. The isolates were further identified using Bergey’s Manual of Determinative Bacteriology. The highest total heterotrophic count for swab samples was gotten from Household A and Household B which both recorded TNC bacterial count and the lowest count was 2.33±0.57 ×10 1 CFU/mL which was gotten from Hall 3A, while that of water samples recorded the highest from 2.67±0.57 ×10 3 CFU/mL which was gotten from Sample B and the lowest was 2.33±0.47 ×10 3 CFU/mL which was from Sample A. The highest total coliform count in swab samples was 7.63 ± 0.58 ×10 3 cfu/mL which was gotten from Hall 4 and the lowest was 1.00 ± 0.57 ×10 2 cfu/mL gotten from Hall 2A, while for that of water sample recorded the highest as 2.33±0.94 ×10 3 cfu/mL which was gotten from Sample A and recorded the lowest as 1.67±0.57 ×10 3 cfu/mL which was gotten from Sample B. The highest total count for Non-lactose fermenting Gram-negative bacteria for swab was 6.60± 0.58 ×10 3 CFU/mL which was gotten from Hall 3A and the lowest was Hall 1B and hall 4 which showed no growth, while for water samples, the highest was 2.63±0.48 ×10 3 CFU/mL which was gotten from Sample A and the lowest was gotten from 1.00±0.58 × 10 3 CFU/mL which was Sample B. The predominant isolates identified included Escherichia coli, Klebsiella sp., Enterobacter sp., Citrobacter sp., Proteus sp., Pseudomonas sp., Staphylococcus aureus and weakly fermenting E. coli. This study has shown that the water stored in the halls of residences in University of Benin stores different varieties and levels of bacterial contamination indicating that the water is not entirely safe for domestic use without proper treatment