The Department of Education says the Island's secondary schools sell around 7,000 plastic bottles of water in an average week.
A Freedom of Information request asked for details about single-use plastics and bottled water sold in schools.
In its response, the department said only Ramsey Grammar School sells no bottled water - because it sells cartons instead.
And it added St Ninian's and Ballakermeen High Schools made around £94,000 from sales last year, but QEII and Castle Rushen High Schools couldn't provide the sales figures.
Delays to buses this morning
Changes to 1st time buyers schemes planned
Nobody will lose benefits after MiCards, says minister
Further weather warning in place for later today
Minor Injuries Unit based at Noble's from today
Vandals hit community centre play equipment
Buses to be diverted in wake of Storm Bram
Parts being made to repair power station