What Human Activities use the Most Water?

When was the last time you had a glass of water? What about 82 gallons of water? That’s how much H2O the average American uses each and every day. This crucial resource enables everything from hydration to hygiene— and that’s only looking at personal usage. Outside of the domestic sphere, water allows us to grow food, create energy, build infrastructure, and manufacture all kinds of goods, however, what human activity uses the most water?

Although water is a renewable resource, we still need to conserve it in order to meet everyone’s needs. Here is a great lesson plan on  Drought Causes: Climate Change Impacts. So, how can we preserve the Earth’s most important resource? To begin to answer this question, it might help to identify some of humanity’s most water-intensive activities. What human activity uses the most water? It depends on how you frame the question.

Human Impact on Aquatic Environments

When you add up all usage in all spheres and sectors globally, what human activity uses the most water? The biggest piece of the pie, it turns out, is agriculture. Irrigating crops takes a lot of water— we’re talking 70 percent of global freshwater withdrawals according to The World Bank. This video from Khan Academy explores human impacts on aquatic environments and discusses many topics including coral bleaching, toxic pollution, dead zones, and oil spills. There is also an interactive quiz about various forms of water pollution on this site. 

Unsurprisingly, some agricultural methods are more water-intensive than others. For instance, drip irrigation (using plastic pipes with holes in them to send water directly to plants) is much more efficient than flood or furrow irrigation (letting the water run along the ground among the crops) according to  The USGS Water Science School. Farmers can also conserve water by monitoring soil moisture levels and the seasonal water needs of crops in order to use only as much water as necessary, and by keeping tilling to a minimum so as to keep water in the soil. For more information about irrigation check out  Sustainable Agriculture Techniques.

In addition, some agricultural products require much more water than others. As a rule, foods further up the food chain and processed foods tend to be more water-intensive. A 6-ounce steak takes 687 gallons of water to produce!  The Water Footprint Calculator has a great interactive tool to easily minimize your own water footprint. While agriculture is what uses the most water in the world, it’s not the whole picture. There are opportunities to save water in many aspects of our society.

Youth Climate Story: Drought in Nevada

In our day-to-day lives, in our homes, what human activity uses the most water? For the average American, the answer is toilet-flushing. However, not all toilets are created equal. If you own your home, consider installing a water-efficient toilet. A 2017 water-efficient toilets study found that if all toilets in the U.S. were switched to water-efficient models, it could save around 360 billion gallons of potable water per year! Other ways to save water in the bathroom include peeing in the shower and only flushing solid waste. In this 3-minute video, students will learn about Celeste Tinajero from Reno, NV who led several initiatives at her school to reduce water waste, decrease water use, and install a hydration station at their school. This is an inspiring video, as her environmental club received two grants for her school to install water-saving toilets and sinks, energy-saving lights, and a filtered water station for reusable water bottles.

By identifying what human activity uses the most water, we can hone in on one of the top priorities for individual conservation. However, there are many other ways to save water at home. To name a few: 

• Run fewer loads in the washing machine by washing full loads.
• Turn off the faucet while brushing your teeth, shaving, and washing dishes.
• Take shorter and fewer showers.
• If you have a lawn, water it with a sprinkler system instead of by hand. Better yet, don’t have a lawn! You can replace grass with drought-tolerant groundcovers or a vegetable garden. Perennial Drought-Tolerant Ground Covers and 15 Drought-Tolerant Groundcovers That Look Gorgeous Without Much Water articles can help find the best plants that will suit your needs. You can ensure the plants are well-suited to your climate —all while supporting local wildlife— by growing native plants by using the native plant finder.
• A  greywater reuse system takes water from your sink, shower, and washing machine, and uses it to irrigate your garden. For a low-tech version, you can place a bucket in the shower, then bring the water you capture to your plants.
• If you have a car, wash it with a sponge instead of a hose. If you do use a hose, make sure it’s one with a shut-off nozzle.

Many products take a great deal of water to produce. You can save water by buying less stuff, avoiding water-intensive agricultural goods like animal products and processed foods, cutting down on food waste, and using less electricity as well as using the water footprint calculator.

As we deal with water shortages, we’ll need to get creative. One helpful piece of technology is atmospheric water generation research, which draws water out of thin air! Using technology similar to a dehumidifier, AWG collects the tiny water particles that float in the air around us. However, there’s a catch— this technology requires a lot of energy.

According to The Water Crisis website, 1 in 9 people lack access to safe water. In this World Water Development Report, we can expect this problem to get worse. Demand for water is going up at the same time that an increasing number of water supplies are becoming contaminated. To address this crisis, it is important to consider not only what human activity uses the most water worldwide, but also what power dynamics play into that water use. As is the case with most environmental issues, water shortages and contamination disproportionately impact poor communities, communities of color, and formerly and currently colonized people. This disparity is no accident. Polluters leave toxins in marginalized communities, contaminating their water supplies. Wealthy nations divert water from poor ones.

Droughts bring with them many social ills. Crops and livestock die, creating famines. Wildfires become deadlier and more destructive. In this Youth Climate Story: Drought in California lesson plan a teenager talks about the impacts he and his family have felt due to long-term drought in the state. Scarcity breeds political conflict and war. We have no choice but to transform human uses of water-- to treat it like the precious resource that it is. Making these changes will require both individual and collective actions. We can combat the global water crisis, individually and together. Want to learn more about what human activity uses the most water and other big environmental questions?