In an email to parents last night, Deputy Head Paul Curran said the school had been informed of a burst main underneath the tarmac in the school.
As a result, the primary and secondary school are both closed today.
He explained: “This required immediate attention, but we have been told by Jersey Water that we must cut off the school’s water supply for tomorrow.
“This means that the school will have to close tomorrow while these repairs are carried out.”
Mr Curran added that contractors had been on site since 17:30 last night and initially expected to complete repairs yesterday evening, but the school later found out this wouldn’t be possible.
Year 6 SATS tests, and GCSE and A level exams are both able to go ahead today, but students were advised to bring their own water bottles “as they will not be able to be filled on site”.
Other students have been set tasks to complete online.
Mr Curran added that the convent school expected to be open again on Wednesday morning.
