Bans on hosepipe and sprinkler use in south-east England have been extended with new restrictions from both Southern Water and South East Water.
The region has had nine months of below-average rainfall
Southern Water has enforced a ban in Kent and Hastings with patrols across the South East from Saturday.
South East Water has also introduced bans from Saturday, for customers across Sussex and in west Kent.
The firms said the step was being taken as the region was enduring its ninth consecutive month of low rainfall.
A ban is already in force across Southern Water's Sussex supply area and even in parts of Kent without a full ban people are prohibited from leaving hosepipes and sprinklers unattended.
Extra water use
South East Water said it was the first time it had been forced to introduce restrictions on water use since 1995.
Its director of operations, David Shore, said water levels had been hit by below average rainfall but also by over-use of water by customers.
He said: "In one weekend recently our customers used an extra 65m litres over a three day period, compared to normal weekend demand, which resulted in water levels at our three strategic reservoirs in the region dropping significantly."
Southern water said the region was experiencing its driest period since the drought year of 1976.
Spokeswoman Penny Hodges said: "Recent rain has helped to keep demand down over the last week or so because people haven't been using it on the gardens.
"But what it hasn't done is made up for the months of below-average rainfall that we have just experienced.
"So the resources and water sources and reservoirs are still much lower than they should be at this time of the year."
Ms Hodges said staff would be patrolling the area in vans equipped with loudspeakers, particularly on hot days, and relying on customers being vigilant.
"We've had an awful lot of customers in other areas where we have introduced restrictions ringing us up and making us aware of people in the neighbourhood who are still using their hosepipes," she said.
"From that we can write to customers explaining the situation and hopefully they will take the messages on board."