Parents of pupils at All Hallows Catholic High School on Crabtree Avenue have been advised to make arrangements to collect children or ensure they have access to homes.
A spokesman for the school said that parents have been contacted via text and email.
A statement on the school's website says: "Due a burst water main the school is without water. We have taken the decision to close All Hallows at 12.30pm.
"Parents may collect pupils anytime from now. Buses will be arriving to take pupils home shortly."
Parents are advised to check the school's website to confirm it will be open tomorrow.