Water companies accused of wasting 1.2 billion litres of water every day
Southern Water said tackling leaks is a "high priority"
Southern, South East, South West, Thames and Yorkshire Water leaked the equivalent of 16 million bathtubs every 24 hours, according to a union.
The GMB said the five private water companies, who have announced hosepipe bans, "wasted" 1.2 billion litres of water between them every day last year.
The union said in total, the five companies lost 460 billion litres of water in the financial year 2020/21.
Andy Prendergast, GMB National Secretary, said: "Tens of millions of people face a hosepipe ban while these privatised companies let more than 500 Olympic-sized swimming pools’ worth of water go down the plug hole every single day.
"It’s a disgrace that customers face a £1,000 fine as private water fat cats trouser millions, all the while failing to sufficiently tackle leakage and refusing to invest in the workforce.
"Privatising water has been a disastrous failed experiment, it’s time to bring this essential natural resource back into public hands."
A Southern Water spokesperson said: "Tackling leakage is a high priority for us – last year we fixed 22,000 leaks.
In Hampshire and the Isle of Wight, where we have a hosepipe ban in force, we’re repairing 250 a week.
"Importantly we have installed 7000 acoustic loggers across our network which detect and pinpoint leaks and 100 of the Hampshire repairs come from this data.
"These leaks are often on major mains buried deep underground and are invisible on the surface but can lose far more water than the visible leaks from communication pipes close to the surface."