The threat of water scarcity is an issue that constitutes one of the biggest challenges to Pakistan. Therefore, alternate water sources including rain water harvesting (RWH) is dire need of the time. The present study applied SWMM V 5.0 to analyse the stormwater and evaluate the potential of RWH in managing the stormwater in the study area, i.e., an industrial estate named Quaid-E-Azam Apparel Park (QAAP) located at M-2 near Sheikhupura, Pakistan. After analysing model on two, five and ten-year return periods, results show that the maximum flow at outfall with stormwater of two-year return period without RWH was 693 cusecs (19.7 cumec) and with RWH it was 529 cusec (14.98 cumec) thus a reduction of 24%. Furthermore, with RWH, there was 9% reduction in flooding of manholes, flooding time of manholes reduced significantly and with RWH many manholes stopped flooding. Moreover, with RWH the O&M cost of pumping station is reduced by 26%.