Rice is the world’s thirstiest crop by total volume, consuming over 1,000 cubic kilometers of water per year. But the full picture depends on whether you’re asking about total global usage or water per unit of food produced. Agriculture accounts for 72 percent of all freshwater withdrawals worldwide, and a handful of crops drive the bulk of that demand.
Rice Tops the List by Total Volume
Rice requires more water than any other food crop on the planet. In 2020, global rice production used roughly 1,035 cubic kilometers of water per year, and that figure climbs to 1,183 cubic kilometers when you include the water needed to flood paddy fields before planting. To put that in perspective, producing one kilogram of milled white rice evaporates about 1,444 liters of water and pollutes another 131 liters through fertilizer and pesticide runoff.
The reason rice is so water-intensive comes down to how it grows. Most rice varieties spend weeks or months standing in flooded fields, which prevents weeds but demands enormous volumes of water that evaporate or seep into the ground. Of the 1,444 liters needed per kilogram, about 764 liters comes from rivers, lakes, and groundwater (the water we actively pump and divert), while 680 liters comes from rainwater absorbed through soil. That heavy reliance on actively managed water sources is what makes rice particularly vulnerable to drought and groundwater depletion.
Soybeans, Maize, and Cassava Are Growing Fast
While rice holds the top spot, several other staple crops are catching up quickly. Cassava now uses 82 percent more water than it did in previous decades, driven by expanding cultivation across Africa and Asia. Soybeans use 60 percent more, and maize (corn) uses 45 percent more. These increases reflect both rising global demand for food and animal feed and the expansion of farming into new, often less water-efficient regions.
Maize is a useful example of how geography shapes water use. Research comparing different climate zones in Egypt found that growing corn in the hottest, driest region (Upper Egypt, where summer temperatures hit 41°C) required about 8,007 cubic meters of water per hectare. The same crop in the milder Nile Delta needed only 6,211 cubic meters per hectare, roughly 22 percent less. On less fertile soils in the hottest zone, the water footprint per ton of corn produced was more than double what it was on good soil in a cooler area: 2,232 versus 1,067 cubic meters per ton. The takeaway is that the same crop can be a moderate or extreme water user depending on where and how it’s grown.
Sugarcane Needs a Steady River of Water
Sugarcane is one of the most water-demanding crops per acre. A single growing season requires between 1,500 and 2,500 millimeters of water, delivered through rain or irrigation over roughly 12 to 18 months. For context, that upper range is about the total annual rainfall of a tropical rainforest climate, except sugarcane needs it concentrated during its active growing period.
Daily water consumption ranges from 2 to 6 millimeters depending on the growth stage and local conditions. During peak growth in hot weather, a sugarcane field can drain the equivalent of a swimming pool’s worth of water per hectare every few days. Because sugarcane is grown heavily in Brazil, India, and Thailand, regions where water stress is already a concern, its footprint carries real consequences for local water supplies.
Cotton and Almonds: Small Crops, Big Footprints
Not every water-intensive crop is a food staple. Cotton, the foundation of the global textile industry, requires an average of 2,745 cubic meters of water per ton of raw fiber. About 65 percent of that comes from irrigation rather than rainfall, meaning cotton farming puts direct pressure on rivers and aquifers. The environmental cost is well documented: the near-disappearance of the Aral Sea in Central Asia was driven largely by cotton irrigation diversions.
Almonds tell a similar story on a smaller scale. A single California almond requires about 12 liters (3.2 gallons) of water to produce. Across the state’s almond orchards, that adds up to roughly 10,240 liters per kilogram of kernels. California produces about 80 percent of the world’s almonds, and virtually all of that water comes from a state already facing chronic drought. Almonds have become a flashpoint in debates about agricultural water use precisely because they’re a high-value, high-water crop grown in a place that can’t easily spare it.
Why Climate Zones Change Everything
The same crop can have a dramatically different water footprint depending on temperature, humidity, soil quality, and rainfall. Hotter regions lose more water to evaporation, so plants need more irrigation to compensate. Wind speeds up moisture loss from soil and leaves. Sandy or degraded soils hold less water, forcing farmers to irrigate more frequently.
Research in Egypt found that maize water use per ton increased by 33 percent between the mildest and hottest climate zones, and wheat increased by 29 percent. On newer, less fertile farmland, the gap was even wider. This pattern plays out globally: a rice paddy in Southeast Asia with heavy monsoon rainfall uses far less pumped water than one in arid northern India that depends entirely on irrigation wells.
This matters because climate change is pushing agriculture in exactly the wrong direction. Projections show that the probability of crop yield failures could be 4.5 times higher by 2030 and up to 25 times higher by 2050 across major growing regions. India, China, and the United States face particularly high water scarcity risk in their most productive farmland. If groundwater depletion makes irrigation unreliable in these regions, crop failure rates will climb sharply for rice, soybeans, maize, and wheat.
Drip Irrigation and Other Ways to Cut Water Use
The most effective single change for reducing crop water consumption is switching from flood or sprinkler irrigation to drip irrigation, which delivers water directly to plant roots through slow-release tubes. Drip systems can cut water use by up to 60 percent while increasing crop yields by as much as 90 percent compared to conventional methods. The efficiency gains are especially dramatic for high-water crops like sugarcane and cotton, where flood irrigation wastes enormous volumes to evaporation and runoff.
Cost has historically been the barrier. Drip systems require upfront investment in tubing, filters, and pressure regulators that many small-scale farmers in developing countries can’t afford. Engineers at MIT and other institutions have been working on low-cost designs that reduce the price of drip systems, but adoption remains slow in the regions where water savings would matter most, particularly South and Southeast Asia, where rice and sugarcane dominate.
Other strategies include breeding crop varieties that tolerate less water, shifting planting schedules to align with rainfall rather than relying on irrigation, and in some cases relocating production to regions with more natural rainfall. Canada, for instance, is projected to see increasing crop yields as climate zones shift northward, while parts of the current U.S. breadbasket face declining productivity. The geography of water-intensive agriculture is likely to look quite different by mid-century.