A New England Patriots spokesperson apologized Monday, one day after the team charged fans at least $4.50 for tap water at Gillette Stadium.

With the temperature hitting an unseasonably high 86 degrees in Foxborough, Massachusetts, the team doubled its inventory of water bottles for Sunday's game, the Boston Globe reported. That was almost four times the inventory for an average game.

The problem was that each concession stand could hold only so many bottles.

When the on-hand supply ran dry, fans started asking for cups of tap water -- and, according to numerous tweets, were charged $4.50 or $5 per soda cup. The tap water was the only option available until more bottles could be brought to individual stands throughout the stadium.

We are being told at the Patriots Game today when it's 90 that we have to pay $4.50 for tap water when they have run out of bottled water — Alan Blankenship (@alcurtis48) September 24, 2017

"We apologize. That should not have happened," Patriots spokesperson Stacey James said in a statement to reporters. "It is the first time that I have ever heard that complaint here. We are looking into the matter to ensure that it doesn't happen again."

The Patriots (2-1) defeated the Houston Texans 36-33 in the game.