A hosepipe and sprinkler ban is being imposed on people in Kent and Sussex.
South East Water said it had no choice after the demand for drinking water had reached “record levels” in June.
It said customers had used a similar amount of water as in the drought last year, adding: “Despite asking for customers help to use water for essential uses only, regrettably we’ve now been left with no choice.”
The ban is to be imposed from 00:01 BST on 26 June.