Water quality and human impacts

Why is water quality important? How is water quality measured?
The US EPA has set water quality standards in accordance with the Clean Water Act: Water quality standards are important because they help to protect and restore the quality of the Nation’s surface waters, consistent with the requirements of the Clean Water Act. Standards help to identify water quality problems caused by, for example, improperly treated wastewater discharges, runoff or discharges from active or abandoned mining sites, sediment, fertilizers, and chemicals from agricultural areas, and erosion of stream banks caused by improper grazing practices.* The impacts of nitrates and phosphates on water have been gaining increased press. But, from the list above, one can see that these are not the only impacts that need attention.

* water.epa.gov