Engineers from United Utilities were called out to the William Howard School in Brampton this morning to fix a water supply problem that closed the school.
Over 1,500 pupils were sent home after registration when staff felt it would not be safe to keep the school open.
No other properties in the area have been affected by the issue.
A spokeswoman from United Utilities told the News & Star:
“It seems to be a problem with the school’s own pipework. A pipe may have burst in the school grounds so we have given advice and helped as much as we can but it is not our pipework so we have left the situation with the school.”
More top news
Campaigners gathered in Kendal for a victory rally, after a decision to keep the town's Kentmere mental health ward open.
Emma Jesson brings you Saturday's forecast for the Border region
It is the final chance for people to have their say in Stage Two of the public consultation into a new nuclear power station in Cumbria.