The potability and qualities of Olumirin waterfall, Erin-Ijesa were investigated by determining the total bacteria and coliform count with antibiotic susceptibility of the isolated bacteria and physico-chemical qualities of the water samples. Total bacteria and coliform enumeration were determined using pour plating and multiple tube techniques, the antibiotic susceptibility were carried out using disc diffusion method, while physico-chemical and mineral studies were also carried out using standard methods. The mean total viable count of the water samples ranged 14.8 x 102 CFU.ml-1 - 21.3 x 103 CFU.ml-1 while the coliform count ranged 13 -175 MPN/100ml. The identified bacteria isolates and their percentage distribution were E.coli (43.1%), Klebsiella spp (20.7%), Proteus spp (12.1%), Salmonella spp (6.99%), Pseudomonas spp (5.17%), Shigella spp (6.9%), and Enterococcus spp (5.17 %). Antibiotic resistance shown by bacteria isolates were exhibited as follow; Nalixidic acid (31%), Ampicilin (76%), Cotrimoxazole (60%), Gentamicin (19%), Nitrofurantoin (24%), Colitin (48%), Streptomycin (34%) and tetracycline (52%). 82.8% of the isolate exhibited multiple antibiotic resistance. The physico-chemical analysis also revealed the presence of some mineral elements in the water samples. The mineral value of the water samples include; magnesium (84.8 - 93.4) mg.L-1, phosphate (12.6 - 17.1) mg.L-1, sodium (47.8 - 87.6) mg.L-1, potassium (76.6 - 104.5) mg.L-1, chloride (59.0 - 90.2) mg.L-1, zinc (0.75 - 1.82) mg.L-1, lead (0.12 - 0.33) mg.L-1, iron (0.52 - 0.60) mg.L-1, copper (0.12 - 0.27) mg.L-1 while nickel and arsenic were not detected in any of the water samples. Comparing the experimental results with the international water standard for natural water, the waterfall is not fit for consumption or for any domestic purpose unless being treated. Also, problems that may arise from the resistance bacteria strains can be tackled while the new antibiotics can also be developed.