According to the Department of Environment, numerous rivers, and streams in Selangor, and practically all rivers, are in the 'polluted' and ‘slightly polluted' category even before the COVID-19 outbreak (DOE, 2022). Due to a lack of anthropogenic activities such as industrial discharge, agricultural, poultry, sediment, and silt erosion, the trend of pandemic lockdown on water quality parameters in Selangor is expected to decline. The goal of this research is to see if contamination of water resources and rivers increases or decreases during a pandemic by examining the trajectory of water quality parameters in relation to the COVID-19 pandemic, to figure out which parameters are affecting pollution in Selangor rivers, and to emphasize the water quality in each river for DOE (2022), utilizing data from 2016 to 2020. The results of the investigation revealed significant variations in water and wastewater quality over time. Finally, it showed positive changes during the pre-pandemic and pandemic lockdown periods. DO, TSS, ammoniacal nitrogen, and turbidity exhibited positive effects on water quality metrics during the pandemic lockdown period, however, BOD, COD, and pH levels had negative effects.