Samples of borehole water were collected from Iperu, Ilishan, Sagamu, Ogere, Ilara, Ikenne, Irolu, Oderemo
and Babcock community, all in Ogun state. They were analyzed microbiologically using pour plate
technique for total viable counts and tube fermentation technique for Most Probable Number (MPN)
counts. Thirteen samples were positive for coliforms while remaining five were non-coliforms. Three
samples satisfied the W.H.O. standard requirements of coliform count between 1-3/100 ml. Four
samples were suspicious having coliform count ranging from 4-8/100 ml and eleven samples with too
numerous counts did not satisfy W.H.O. standard requirements. Six bacteria isolates were obtained
from the samples and identified as Escherichia coli, Klebsiella sp., Proteus sp., Enterobacter
aerogenes, Staphylococcus aureus and Streptococcus sp. Characterization of isolates was carried out
by Gram staining reaction and biochemical tests. Gram-negative bacilli (72.22%) were more prevalent in
the water samples compared to Gram Positive Bacilli (11.11%) and Gram Positive Cocci (16.67%). E. coli
gave the highest percentage of occurrence of isolates (33.33%) followed by Klebsiella sp. (27.78%)
while the percentage of occurrence of Proteus sp., S. aureus and E. aerogenes were the least (5.56%).
Two samples were confirmed for Streptococcus sp. (11.11%) and Clostridium sp. (11.11%). 50% of the
isolates tested positive to acid and gas.