Rainwater harvesting for portable and non-portable use has gained popularity in developing countries due to failure of conventional means of water supply for its increasing population, industrial and commercial activities. The objective of the study is to determine the quality of harvested rainwater with increasing urbanization. Rainwater samples were harvested from different locations in Owerri, Imo state, Nigeria and its physiochemical and microbiological quality analyzed using standard methods and procedures. The results were compared with WHO standards for drinking water and subjected to statistical analysis. The rainwater samples at the different locations showed statistically significant differences p (0.05) < alpha (0.708). The physicochemical quality was affected by increased amount of sulphate (484.81 ± 115.02)mg/l, color (56.23 ± 14.59)PCU, turbidity (23.92 ± 6.20)NTU, phosphate (25.03 ± 20.32)mg/l, phosphorus (8 ± 6.59)mg/l and heavy metals (0.92 ± 0.84)mg/l. Though there was no fecal coliform contamination, the microbial concentration (11.95 ± 5.04) in the present study exceeded standards. It is concluded that the harvested rainwater is not suitable for direct drinking without treatment but it could be used for other domestic purposes.