Classes were cancelled yesterday for students in the Malta ISD because of a water leak, and a boil-water advisory is in effect for customers of the Central Bowie County Water Supply Corporation between the Red River and US 67 and from Highway 8 to FM 2789/FM 990. A loss of water pressure prompted the state environmental quality commission to issue the boil advisory yesterday. Customers in the affected area are advised to boil water for at least two minutes before consuming it until the advisory is lifted.