Green, Blue, and Grey Water

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Do you know what the color codes mean in water production?

As a company, we like to think of ourselves as sustainability advocates. In the past, we took deep dives into sustainable farming practices and eliminating food waste.

As climate change progresses, we feel like we collectively have a responsibility to understand how water impacts food production and how we can all work together to protect this invaluable natural resource.

According to the United Nations, approximately 20 percent of the world’s population lives in water-scarce areas; another 25 percent face a water shortage. With numbers like these, the importance of water as a commodity becomes evident.

When we’re speaking of water footprints in food production, water comes in three colors: green, blue, and grey. Knowing the color code of the water used in production can help you make a more informed choice when deciding how to create a more sustainable packaged food.

Green Water

“Green Water” is the amount of rainfall that is either intercepted by the vegetation, or enters the soil and is picked up by plants and evaporated back into the atmosphere. Some 65 percent of all rainwater is cycled through the green water cycle and is the water source for rain-fed agriculture. One of its benefits is that harvesting green water produces minimal consequences on our environment.

Green water is non-competitive with urban water needs. However, a green water system is highly vulnerable to climate change and drought. If farmers and other food suppliers cannot capture enough rainwater to successfully harvest a product, they will need to tap into a “blue water” source. (We’ll get to that.)

To find suppliers practicing green water best practices, look for farmers who utilize aquifers to conserve water for drier periods. Planting cover crops can help lower crops retain more water naturally under shade. Rotating crops who love drier conditions, like grapes and olives, can also help conserve water while increasing agricultural output.

Blue Water

“Blue Water” is the water most of us are familiar with – groundwater. In farming, it looks like irrigation and surface water. In food manufacturing, it is your standard tap water used run machinery, cool facilities, and up to 60 percent of water consumption is tied to cleaning processes.

Blue water is often the backup source when food producers cannot source enough rainwater.

When thinking about sustainability, we also look at how many gallons are used to produce a pound of food. In 2012, irrigated farms accounted for roughly half of the total value of crop sales on 28 percent of U.S. harvested cropland. About 10-15 percent of corn, about 8 percent of soy crops, and 33 percent of alfalfa crops are irrigated.

While green water is most vulnerable to climate change and weather conditions, food producers depending on blue water are most vulnerable to changes in municipal and state policy. Competing demands over water resources can spark battles over water rights, allocations, and use between sectors, in court, and in the larger community.

Grey Water

“Grey Water” is often a grey-area of sorts when it comes to repurposing this water supply for use. Grey water includes used shower and bath water (not toilet water) that can be recycled for subsurface irrigation as an alternative to using more valuable blue water.

Grey water can also include indirect water pollution because of farm field runoff of fertilizers and pesticides that were applied to corn and soy crops. Synthetic fertilizers are one of the primary causes of dead zones in US freshwater and marine systems.

It’s worth noting that grey water is more alkaline than rainwater, and it is not suitable for crops that normally grow in acidic soils.

Despite its additional safety precautions, when used properly, grey water can help businesses achieve a neutral water footprint. We anticipate that we will see continuous developments in water filtration technology to open up more grey water use as climate change affects availability of green and blue water sources.

Now we challenge you to leave us a comment below.

Do you know how much water your favorite snack requires to produce one serving? Do you know how or where they source their water?

One Response

  1. No I do not know how much water it takes to produce my favorite snack nor do I know the source of the water. To tell the truth I never really gave it much thought.
    I do think about how our food is grown and how we can grow our own. I think mostly about the soil even though I know water is important also.

    I have heard of grey water, never heard of blue or green water. I am more familiar with terms like alkaline and ph of water.

    The information about the types of water is
    good information especially if you are farming

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