The water company introducing a hosepipe ban has been accused of “wasting” 430 million litres of water every day from leakages.
The GMB union said its research showed that United Utilities was allowing 175 Olympic-sized swimming pools’ worth of water to go “down the plughole” every day.
The North West-based company, which is banning the use of hosepipes from August 5, said it had cut leakages by half since the 1990s.
Stuart Fegan, GMB national officer, said: “It’s a disgrace that customers face a £1,000 fine as private water fat cats trouser millions, all the while failing to invest to tackle leakages.
“While we have had hot weather, the UK uses less than 2% of the water that falls from the sky each year and which flows into the sea.
“Whatever the weather, we need to take back the tap and ensure our water services are run in the interests of the public once more and not just the few at the top.”
A United Utilities spokesman said: “Reducing leaks is a top priority. We have cut leakage by half since the 1990s and are working hard to do even more.
“For instance, we now use satellites to help to detect leaks, and we have just recruited a team of sniffer dogs trained to pinpoint leaks in rural areas where the water does not always show on the surface.
“The company takes the issue of losses of water from its distribution network very seriously and every year invests millions of pounds to minimise the amount of water lost.
“Currently, there are over 160 full-time inspectors detecting leaks across the region. Since the Beast from the East severe weather event in February and response to the ongoing drought, we have increased both our leakage detection and repair activities by around 50%.
“In addition to traditional detection methods, we are also investing in emerging satellite technology to help spot leaks.”
The union said water companies in England and Wales lost three billion litres of treated water every day in 2017.