South West Water says it was “left with no other choice” to “protect our precious water”.
A hosepipe ban is to start in Cornwall for the first time in 26 years amid a continuing drought.
South West Water (SWW) said it had been “left with no other choice” to “protect our precious water”.
The ban, which includes parts of north Devon, will begin on 23 August.
Activities to be banned include using hosepipes to water gardens or clean cars. Businesses and farmers are unaffected.
Lisa Gahan, of SWW, said it was the “right thing to do” in the “extremely hot and prolonged dry weather”.
“We’ve done our best to avoid this ban,” she said.
“In the last two years we’ve doubled the amount of leak detection staff and now fix about 2,000 leaks a month.
“Thirty per cent of leaks happen on customer supply pipes, we’ve offered to fix these leaks for free.”
Customers will still be able to water gardens or clean cars without using a hosepipe if they use tap water from a bucket or watering can.
Or they can use water that is not sourced from taps such as grey water, rainwater from a water butt or a private borehole.
The temporary measure will not apply to blue badge holders or those on SWW’s priority register.
SWW said the ban also covered some households in the Upper Tamar region of north Devon and there was a postcode checker on its website. where people could see if they were affected.