Students at Aberarder Central School were dismissed early Wednesday.
The Lambton Kent District School Board (LKDSB) said it had to close the public school in Camlachie due to a break in the school's water line.
Parents and guardians were asked to pick their children up from school as soon as they were able.
Bus students, who weren't picked up by noon, were taken home by bus.
*The LKDSB said the school reopened Thursday as repairs were made to the water line.