More often than not, we take for granted the clean water that we drink directly from our taps. We fill a glass from the faucet, and drink without giving it a thought. However, pollution can impact the suitability of water not only for drinking water treatment, but for other purposes such as protecting aquatic life and recreation (e.g. swimming, water sports). Where do pollutants come from and how do they move in the environment? How do we try to control and minimise pollution so that water remains suitable for beneficial uses? This course seeks to answer these questions by focusing on the science and quantitative elements that will facilitate the understanding of water pollution in the environment. Case studies from Singapore and other countries will be used to demonstrate the concepts covered in class, where relevant.