Liverpool King David students enjoyed an extended winter holiday when a problem with the water supply forced the closure of the campus on Monday and Tuesday.
When the issue was discovered on Monday morning, parents of primary pupils were asked to collect their children. High school students were told they could go home.
In an email to parents, high school head Brigid Smith wrote: "The decision to close the school was not taken lightly.
"The water problems were resolved on Tuesday afternoon and were completely out of the control of the campus. With no water supply - which meant no toilets, cleaning or cooking facilities - it was impossible to keep the campus open."