The Langat River in Selangor, Malaysia was studied to assess its water quality and microbial contamination in 2016. Different points along the river were tested for oxygen levels, pollution levels, and bacteria counts. The midstream point with effluent discharge was found to be the most polluted, while the upstream point had the cleanest water. Overall, the Langat River was classified as moderately polluted, indicating a need for treatment before using the water for domestic purposes.