Water is the world’s most fundamental natural resource, sustaining all biological life and driving human civilization. Although the planet is covered in water, the available freshwater is a finite supply that humanity relies on for survival and economic activity. This dependency necessitates managing this resource across several broad categories of use that reflect the diverse needs of modern society.
Household and Personal Needs
Water use within the residential sector focuses on the direct, daily needs of people living in homes and communities. This category encompasses immediate uses, such as providing clean water for drinking and preparing food. Access to safe drinking water is a foundational requirement for public health.
Water is also used for sanitation, primarily flushing toilets, which is a major component of indoor residential use. Personal hygiene activities like showering, bathing, and handwashing also require a steady supply of potable water. This municipal sector typically represents the smallest fraction of global freshwater withdrawals, accounting for approximately 12 percent worldwide.
Water for Food Production
The agricultural sector is the largest consumer of freshwater globally, responsible for roughly 70 percent of all water withdrawals. This demand is driven by the necessity of growing crops and raising livestock to feed the world’s population. Most of this water is applied through irrigation, which supplements natural rainfall to ensure crop yields, especially in arid regions.
Irrigation maximizes the water consumed by the plant through transpiration, where water moves through the plant and evaporates from the leaves. This is a consumptive use, meaning the water is transformed into vapor or incorporated into the plant tissue and is not available for immediate reuse. Methods like flood irrigation apply vast quantities of water, while precise techniques like drip irrigation increase efficiency by delivering water directly to the plant roots.
Raising livestock also requires substantial water resources for the animals’ direct consumption and environmental maintenance. Large animals like cattle require significant volumes of drinking water daily. Additional water is used for cleaning pens, cooling the animals, and processing animal products. The total water footprint of food production emphasizes the scale of water needed to sustain the global food supply chain.
Supporting Industry and Power Generation
The industrial sector accounts for just under 20 percent of global freshwater withdrawals. Water is utilized in complex processes that underpin modern infrastructure and manufacturing. In manufacturing, water functions as a solvent, a cleaning agent, and a raw input material for creating goods like paper, textiles, chemicals, and refined petroleum products. Advanced manufacturing, such as semiconductor production, requires vast amounts of ultrapure water to clean and process microchips.
Water is also in significant demand for its role as a coolant, especially in thermal power generation plants, including those that burn fossil fuels or use nuclear energy. These facilities boil water to create steam that turns turbines, then require cold water to condense the spent steam back into liquid form. Cooling systems vary, with “once-through” systems withdrawing large volumes of water and returning most of it, albeit warmer.
Recirculating cooling systems withdraw less water but consume a greater percentage through evaporation as the water is cooled in towers before being reused. Water is also the primary driver of hydroelectric power, where the mechanical force of moving water turns turbines to generate electricity. Although the water is not consumed like in agriculture, large hydroelectric reservoirs still result in substantial consumptive water loss through surface evaporation.