What is Blue Water?

Blue water refers to both surface water (water that is above ground, i.e. in streams, rivers, lakes, wetlands, reservoirs, and creeks) and groundwater (water that is below ground, i.e. water that is in the little cracks and crevices of soil, sand, and rock) and typically comes into play when we talk about agriculture or irrigation. Like green water, blue water is a type of virtual water, which is the water we don’t see that goes into the production of food, fiber, and other commodities, including energy (hello, water-energy nexus!). However, unlike green water, the flow of blue water can be controlled by anthropogenic (aka human-controlled) processes.

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Want a hot take? 

While the use of blue water has a higher opportunity cost and higher probability of negative environmental impacts compared to green water, it is a necessary evil in the production of certain products.

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Is Blue Water “good”?

The blue water footprint is the amount of surface and groundwater that is consumed during human activities. Compared to green water, blue water has much larger opportunity costs as well as more negative environmental impacts. When blue water is used for irrigation of crops, the potential for water depletion, salinization, waterlogging, and soil degradation is much higher due to the fact that it can be overused by  unregulated farmers, energy generators, and industrial or household consumers. The benefit of using blue water in production is that it is more readily available than green water because it is on the surface or stored in aquifers and can be pumped more easily.

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What kind of products are made with Blue water?

Blue water is used as a supplemental source of water to green water. Since it is a kind of virtual water it factors into the overall water footprint of a product. When it comes to growing crops, if an area does not get enough water from precipitation (aka green water), farmers will irrigate their land with blue water to ensure their crops continue to grow. 

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Are there certifications I should look out for?

Blue water is not necessarily certifiable, however one thing to look for when shopping is how companies control their “water footprint.” Organizations like the Water Footprint Network help companies take steps to reduce their water footprints in order to sustain their businesses and take precautions for the wellbeing of the planet.

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Still want to learn more? Check out some of our favorite references:

• Agricultural green and blue water consumption and its influence on the global water system
• What to Know About the Water Footprint of Everyday Products
• Water Footprint Network Glossary
• Evaluation of Environmental Impacts Due to Blue Water Consumption in China from Production and Consumption Perspectives