Hoses should be banned, the environment secretary urged water companies, as Britain expects heatwaves of up to 28°C on Sunday amid an unusually dry August.
George Eustis said some firms have already taken “the right steps” to mitigate the effects of prolonged dry weather and urged others to follow suit.
His remarks, the first public intervention by ministers, signal potential restrictions on watering gardens, washing cars or filling pools with hoses for millions of people in the south of England in the coming days.
This is as forecasters predict that warm weather will continue across much of the UK next week, with conditions remaining dry and settling in with little rain or wind.
Southern Water has already introduced a hose ban for customers in Hampshire and the Isle of Wight, and in exactly one week the measure will take effect for South East Water customers in Kent and Sussex.
Welsh Water also announced a ban for Pembrokeshire and Carmarthenshire later this month.
Mr Eustis wrote in The Sunday Telegraph: “In line with their drought plans, water companies across the country have correctly taken action to mitigate the effects of this prolonged dry weather using the range of tools available to them.
“I urge others to do the same.”
Meteorologists have urged people to avoid the midday sun and stay in the shade as the dry weather will continue for another seven to 10 days.
Highs of 27C and 28C are expected to hit parts of southern and southeast England on Sunday, with sunny spells forecast throughout the day for most of the country.
There could be some light rain in the west of Scotland, but there will also be patches of clear skies, according to forecasters.
Met Office Senior Meteorologist Greg Dewhurst said: “England and Wales will be dry with periods of sunshine (Sunday).
“Northern Ireland and parts of Scotland will be more cloudy with the risk of intermittent rain mainly in the west of Scotland, but there will be sunny spells in Northern Ireland.
“The maximum temperature tomorrow will be around 27 and possibly 28 degrees Celsius, which will be in the central, southern and south-eastern parts of England.
“It will still be in the sun further north, even east of Scotland we can see 23C.”
The dry conditions seem to be at odds with the hose ban that has already been or is about to be announced, and more firms are likely to follow suit after the environment minister intervenes.
“It looks like it will be dry in most of the country for the next seven to 10 days,” Mr. Dewhurst said.
Mr Dewhurst also urged people to take warm weather precautions to avoid overheating, including closing curtains and windows during the day.
“As the heat develops, stay out of the midday sun, try to stay in the shade if you’re outside, and it’s best to close the curtains during the day and then open the curtains and windows at night to let in cooler air. in,” he said.
“Drink plenty of water and stay hydrated.”
He added: “In general, August tends to be a wetter month, so it’s rather unusual to have extended dry weather in August.”