How does urbanization impact water quality?

Urbanization typically leads to increased pollution and runoff due to the expansion of impervious surfaces such as roads, buildings, and parking lots. As cities grow, these surfaces prevent water from being absorbed into the ground, resulting in more surface water runoff. This runoff often carries pollutants, including oils, heavy metals, chemicals, and sediments, into nearby waterways.

Additionally, urban areas increase the risk of combined sewer overflows, where stormwater and sanitary sewage mix, leading to significant contamination of water bodies during heavy rain events. The concentration of people and activities in urban settings also leads to greater levels of waste production, which can overwhelm local water treatment facilities and further degrade water quality. Therefore, the impact of urbanization on water quality is predominantly negative due to these factors.