A hosepipe ban will be imposed from next Friday by Southern Water for customers in Hampshire and the Isle of Wight.
The company said there was no risk to water supply but the ban was being put in place to protect the environment during “one of the driest years on record for over a century” and record temperatures.
Dr Alison Hoyle, Director of Risk & Compliance at Southern Water, said: “We haven’t taken this decision lightly and we know the temporary use ban will have an impact on our customers.
“We’re asking everyone in Hampshire and the Isle of Wight to do their bit by supporting these measures and only use the water that they need.”
It is the latest ban to be announced, with restrictions due to come into force at midnight on Friday on the Isle of Man.