Six Flags Great America and its Hurricane Harbor water park are bringing back their chaperone policy a week after shots were fired in the Great America parking lot.

According to the policy, all guests 15 and younger must be with a parent, guardian or adult chaperone 21 or older to enter the park starting at 4 p.m. Six Flags noted, though, that it may start the requirement earlier than for 4 p.m. on occasion.

Six Flags Great America will implement a chaperone policy starting Thursday July 17, requiring guests 15 years old and younger to be accompanied by a parent or adult chaperone who is at least 21 years old.