Jersey's desalination plant will be turned on shortly because of a lack of rain.
We've had less than half the usual amount between May and October - 227mm compared to 485mm in the same period in 2017.
The island's reservoirs are only 46% full.
Jersey Water says it is taking the precautionary measure because the long-term forecast predicts the drier-than-average weather will continue into January.
The plant - which removes the salt from sea water - has not been used since December 2011.
It is likely to be turned on early next month.
Jersey Water Chief Executive Helier Smith says customers don't need to worry and won't see any immediate impact on their utility bills.
"The plant is expensive to run. It consumes the same amount of power as is required by around 4,000 homes. So there is a considerable cost that come with running that plant. Historically, Jersey Water has absorbed those costs. The extent to which we absorb these costs we can't foretell until we know how long we have run the plant for."
Islanders are being urged to use water wisely to help preserve resources, by taking showers instead of baths and checking for leaking pipes.
£75,500 raised in Jersey Christmas Appeal Charity Auction
Government to announce support option for carers
Drink driving can cause 'life-changing' consequences
Parked cars damaged in Victoria Avenue crash
L'Ecume II: Lewis Carr jailed for 20 months for fatal collision at sea
Guernsey's former Chief Minister admits making indecent images of children
Minister approves 42 sheltered homes at nursing home
Jersey potato farm to be the site of Channel Islands' largest roof solar array
