More than 1,500 pupils have been sent home from the William Howard School in Brampton after problems with the water supply.
Engineers from United Utilities have been working with local contractors to try and establish the fault.
Pupils were sent home after after registration at 9.20am.
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A decent weekend. Chilly nights but mainly dry days with sunny spells
The weekend looks promising for most of the region.
More than one in four children starting school in Cumbria have excess weight and obesity, according to Cumbria's Director of Public Health.