Water intensity – the next stage in eco-labeling?

So you’re concerned about water stress. You know you could recycle your greywater, install a low-flow showerhead or water tanks, or even get a composting toilet. You can make your entire home water-smart, and never turn on the tap without thinking twice about it. What else can you do to save water?

In Victoria, only eight percent of water use is domestic. That means even if every resident of Victoria cut their in-home water use in half, we would still be extracting 96 percent of the volume of water from the environment that we do today. And it seems that few people know what to do to conserve water apart from minimizing their personal water use.

Agriculture is responsible for 66 percent of water use in Victoria. Therefore, it is the sector where smart water management policies can have the greatest effect. And despite the fact that we seem far away from the places where our food comes from, we have a lot more power over what happens on farms than we think.

Most people have heard of shopping organic, or paying attention to food miles. But what about shopping for water intensity? By being conscious of the relative water intensity of different food products and making purchases accordingly, we can choose to buy food items whose production is sustainable given Australia’s constant state of water stress and reduce our personal water footprints.

Some products require a lot more irrigation than others. In an environment with such scarce supplies of water as Australia, the amount of irrigation a crop receives has a huge effect on the environment. Removing water from rivers, streams, and other natural bodies of water throws off the delicate balance of their ecosystems. Excess irrigation can leach nutrients into our water supply, and cause salinisation of land and water. Therefore, it is important to encourage farmers both to take as little water from the environment as possible, and when they do extract water, to use it in an thoughtful way and return it in good condition.

In the future, we hope that products will be labeled for their water intensity. That way, every time you shop you will be able to judge products for their water intensity and compare individual producers’ water use practices. The label would take into account both the average water intensity of a product and a producer’s individual water use efficiency. This should encourage farmers to improve their irrigation practices for the water intensive products they are already growing as well as to switch to growing foods that require less water. It would also give consumers considerable power to minimise their impacts and support those farmers who are the mots efficient.

In the meantime, you can use the following as a guide when you go grocery shopping—think about how much water goes into what you’re buying and remember that you do have the power to decide how our water is used.

Water intensity and food

In general, processed foods have high water intensities. Many industrial food processes use a lot of water, and although they are becoming more efficient, they tend to produce a lot of waste water. So the virtual water content of processed foods include not only the water required to grow the ingredients, but also the large amounts of water used in their manufacture.

The best products to eat for low water intensity are fruits and vegetables. They have a high yield per water input and require little processing. Pumpkin and squash, tomato, sweet potato, lettuce, and strawberries are some of the fruits and vegetables with the lowest water intensity. Grapes, oranges, bananas, and stonefruits have high water intensity in comparison.

Grains, legumes, and cereals have higher water intensities than fruits and vegetables, largely because they are usually processed before they arrive on our plates. Among grains, rice has one of the highest water footprints. Many Australian rice growers are amongst the most efficient in the world. It takes 1,176 litres of water to grow one kilogram of rice in Australia—which is small compared to the global average of 2,300 litres. Even though we live on the driest inhabited continent in the world, we are growing enough rice to feed 40 million people daily. This makes a huge dent on our water supply.

Animal products are uniformly more water intensive than plant products. This is because the water footprint of an animal product includes the water content of their feed, servicing, and drinking. Beef products are the worst due to the long life span of cattle. They consume a lot more in their average three years of life before slaughter than a sheep does in 18 months or a chicken does in ten weeks. In terms of water intensity, it would be best to avoid meat altogether, but if you must eat meat, try to stick to chicken or lamb and steer clear of beef.

Coffee also has a very large water footprint due to the water intensive processes required before we drink it. Tea, by comparison, has a very small water intensity. The virtual water content of a cup of coffee is 140 litres while that of a cup of tea is only 30 litres. Drinking a cup of tea every morning rather than a cup of coffee would save 770 litres of water a week.

Next time you go for a drink, choose beer. The virtual water content of a 250 mL glass of beer is only 75 litres, while it takes 120 litres of water to produce a 125 mL glass of wine.

There is currently very little research on water intensity and the virtual water contents of different foods. Hopefully, as the water shortage becomes more serious, a larger body of information will become available. In the meantime, there is a lot of good information available on www.waterfootprint.org. Happy eating!

Research by Naomi Schwartz