The wastewater treatment plant at the Export Processing Zone in Kenya was evaluated to see how well it reduced pollutants in the water released into River Athi. Samples were collected and analyzed for various pollutants. The plant was not effective in reducing nitrates, phosphates, heavy metals, and some other pollutants, especially during the rainy season. However, it did reduce chemical oxygen demand and biological oxygen demand. Some physical parameters were within acceptable limits. Pollution levels were higher at the discharge point compared to upstream and downstream areas.