Despite the importance of hydration, American school-provided lunches have been accompanied by milk rather than water for decades because of a few interesting reasons.

One reason milk was prioritized over water was a result of a surplus created during WWII where farmers were encouraged to increase their dairy production for soldiers overseas.

In 1940, the U.S. government had to establish its first federal subsidized program, providing low-cost or free milk to select schools in Chicago to address the surplus milk.

Then, in 1955, the Special Milk Program was born. The program stipulated that children would receive a half pint daily, and schools would be reimbursed for the milk they provided.

As per those in the dairy industry, milk was prioritized over water to help school kids meet their daily nutritional needs for calcium and vitamin D, among 13 other nutrients.

Bills regarding the U.S. school’s milk requirements continue through Congress today, such as 2023’s Whole Milk for Healthy Kids Act, allowing 2% and whole milk, for school lunches.

Though schools must make water available, water in schools isn’t subject to the same regulation as milk and 50% of U.S. states have no regulations to test water for safety.