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Will be for 1 hour at a time. Plan according if on island.

Seems to happen more often in high season when the demand gets very high. Another reason we try to stay at hotels or condos that have generator and back up water supply.

If I read it correctly it should last an hour? Or will it be on and off hours at a time?

Says it will be off around an hour at a time in different locations. Not all locations at once.