Stormwater runoff carries pollutants from impervious surfaces, such as roads, parking lots, and rooftops, into water bodies.

Excessive nutrient input, particularly nitrogen and phosphorus, from agricultural runoff and sewage discharge, leads to eutrophication, causing algal blooms and oxygen depletion.

Groundwater is the primary drinking water source for most of the world's population, providing approximately 50% of global drinking water.

The WHO sets the maximum allowable level of lead in drinking water at 10 micrograms per liter (µg/L) to protect public health.

A water quality index (WQI) is a numerical value that combines multiple water quality parameters into a single measure, providing an overall assessment of water quality.

Diarrhea is the most common waterborne disease globally, causing significant morbidity and mortality, particularly among children in developing countries.

The Safe Drinking Water Act (SDWA) is a federal law in the United States that aims to protect public health by ensuring the safety of drinking water.

The Clean Water Act (CWA) is a federal law in the United States that aims to restore and maintain the chemical, physical, and biological integrity of waters.

Increased carbon dioxide (CO2) absorption by the oceans from the atmosphere is the primary cause of ocean acidification.

A total maximum daily load (TMDL) is a calculation of the maximum amount of a pollutant that a water body can receive and still meet water quality standards.

The Water Framework Directive (WFD) is a European Union directive that aims to achieve good ecological status of water bodies.

The Global Water Partnership (GWP) is a global network that promotes integrated water resources management.

Sustainable Development Goal (SDG) 6 of the United Nations aims to ensure access to safe and affordable drinking water for all.

World Water Day is celebrated annually on March 22 to raise awareness about the importance of water and to promote sustainable water use.

The Water Footprint Network is a global network that promotes sustainable water use.