It's a policy that could be set by local school boards, but Mississippi lawmakers are taking matters into their own hands.
A bill that passed the state House last week says students must be allowed to drink water on school buses.
Republican Rep. Becky Currie of Brookhaven says she filed the bill at the request of a constituent.
Currie says it's not right for people to put children "on a tin can in 110-degree weather" and tell them they can't have water.
Democratic Rep. John Hines of Greenville asked what would happen if kids filled bottles with vodka instead of water. Currie said that would, of course, be illegal.
House Bill 348 passed the House on Wednesday. It moves to the Senate for more debate.