During the Industrial Revolution, Grejs River was used as a source of water power for about 14 watermills, which powered textile, paper, and metal factories.
For example, Grejs Mølle Klædefabrik (Grejs Mill Textile Factory) was the country's largest private textile factory in 1830, employing 150 people.
At the height of its activity around the turn of the twentieth century, the river had the highest concentration of industrial mills in the country.

As of 2016, a pumping station was under construction at the confluence of Vejle River and the Omløbsåen branch of Grejs River in order to prevent high water levels in Vejle River and Vejle Fjord from backing up into Grejs River and causing floods.
During the Industrial Revolution, Grejs River was used as a source of water power for about 14 watermills, which powered textile, paper, and metal factories. For example, Grejs Mølle Klædefabrik (Grejs Mill Textile Factory) was the country's largest private textile factory in 1830, employing 150 people. At the height of its activity around the turn of the twentieth century, the river had the highest concentration of industrial mills in the country.
As of 2016, a pumping station was under construction at the confluence of Vejle River and the Omløbsåen branch of Grejs River in order to prevent high water levels in Vejle River and Vejle Fjord from backing up into Grejs River and causing floods.
Grejs River