The virtual water trade is the idea that when goods and services are exchanged, so is virtual water. When a country imports one tonne of wheat instead of producing it domestically, it is saving about 1,300 cubic meters of real indigenous water. 

For instance, water-guzzling activities are getting outsourced for production to other countries. Thus, crops, meat, leather, chemicals, and industrial goods are imported to ensure a positive water balance. For example, Mexico imports maize and in doing so, it saves 12 billion cubic meters per year of its national water resources. 

Countries export less water-intensive crops and products and export less water-intensive commodities to increase their water availability 

Source: Relation between Agri exports and water stress – Explained, Pointwise