What’s the best way to reduce your water consumption? You might do better by keeping the lights off, going out to restaurants less, buying fewer cotton t-shirts and cutting back on how much bread and pasta you eat than by shutting off the tap while you brush your teeth.
Power generation and supply, along with grain farming, are the two most water-intensive industries in the US, according to a comprehensive analysis by researchers at Carnegie Mellon University.
Chris Henderson, Michael Blackhurst and Jordi Sels I Vidal calculated both the direct and indirect water footprints for all 426 sectors of the US economy (based on 2002 data). They found that, while farming and power generation account for 90 per cent of all direct water withdrawals, most water use in the country — 60 per cent — is indirect, via each sector’s supply chains. In fact, 96 per cent of sectors use more water indirectly than they do directly.
When it comes to indirect water consumption, the food and beverage industry dominates, accounting for 30 per cent of all indirect water use.
Producing a single five-pound bag of refined white sugar, for example, takes a full 88 gallons of water from start to finish. Most of that footprint — 84 pounds — comes from the farming of sugar cane and sugar beets.
In fact, in terms of water use per dollar of economic output, agriculture is far more water-intensive than even power generation and supply. The top 10 thirstiest industries, in water consumption per dollar of output, were:
- Grain farming
- Cotton farming
- Sugar cane and sugar beet farming
- Tree nut farming
- Fruit farming
- Flour milling and malt manufacturing
- Power generation and supply
- Wet corn milling
- Beet sugar manufacturing
- Vegetable and melon farming
Interestingly, while meat farming is often targeted as an energy- and carbon-intensive sector, it’s lower on the list in terms of water use per dollar of economic output: number 15 (cattle ranching and farming), after other animal food manufacturing (number 11), sugar cane mills and refining (12), poultry and egg production (13) and dog and cat food manufacturing (14).