Jersey's desalination plant was turned on this week due to the dry summer.
Millions of litres of water will be treated and pumped into the Val de la Mer reservoir for use as drinking water.
The island has received 25% less rainfall this year than the long-term average, according to Jersey Met.
Switching on the plant should ensure there is enough drinking water available for the island's population.
This is the second time this year the plant has been switched on, following a seven-year gap between 2011 and 2018.
The plant removes salt from 10 million litres of sea water a day, before pumping it into Val de la Mer reservoir.
Helier Smith, CEO of Jersey Water, said the plant's activation was a "precautionary measure".
He said: "Water efficiency is something all homeowners should take responsibility for. Water is a precious resource and we don't have a lot of it in the island. No reason to worry, but we must not waste water and every opportunity to save it must be taken."
Jersey Met expects the low rainfall to continue into the winter months.
The plant will was switched on from Monday, but the additional water for the drinking supply is not expected for a further 14 days.