The causes of water pollution can be divided into two groups: anthropogenic sources of pollution are those due to human acts, sources include:

discharge of poorly-treated or untreated sewage industrial discharge of chemical wastes and byproducts runoff contining pesticides and herbicides runoff containing spilled petroleum products runoff from construction sites, farms, or paved and other impervious surfaces e.g. silt discharge of contaminated and/or heated water used for industrial processes acid rain caused by industrial discharge of sulfur dioxide (by burning high- sulfur fossil fuels ) excess nutrients added by runoff containing detergents or fertilizers