This document discusses various causes and types of water pollution. It identifies two main sources of water pollution as point source pollution and non-point source pollution. Point source pollution originates from discrete sources like pipes or drains, while non-point source pollution has diffuse origins from a wide area. Common pollutants include pathogens, nutrients, organic matter, heavy metals, and chemicals from industrial, agricultural, and residential activities. The document also outlines several types of water pollution such as nutrients pollution, surface water pollution, oxygen depleting pollution, and groundwater pollution.