Water companies say they have been inundated with requests from pubs and bars to pour beer down drains.
Millions of pints of beer have gone off in pub cellars since businesses shut in March and now they have to apply for permission to dump it in sewers.
Severn Trent has given consent for 3.5 million litres to be disposed of, while Thames Water has allowed three million.
The Tudor Arms in Gloucestershire said it was “heart breaking” having to flush more than 1,500 pints away.
Thames Water said across the region – which includes Gloucestershire, Wiltshire and the Thames Valley – more than six million pints of beer have been thrown away.
A spokesman said it had been working with the industry to “make sure any spoilt beer is disposed of correctly”.
“There are some risks associated with tipping large quantities of beer into the sewer system,” he said.
“We need to make sure that there is no overwhelming of the network.”
‘Alcohol in moderation’
Grant Mitchell, from Severn Trent, said pubs could not “just throw it down the sewer” but needed to apply to find out “when to do it and in which quantities”.
“The sewage system is a very balanced system and relies on bacteria or bugs treating the sewage for us,” he said.
“Like anybody, too much alcohol can impair you and we don’t want to get the bugs in our treatment works impaired, so we need to feed them in moderation.”
Richard Sims, manager of the Tudor Arms at Slimbridge, said they were given permission to flush 600 litres of beer down the drain.
“We had about 13 or 14 barrels left from lockdown and they [Thames Water] gave us three days to do it in,” he said.
“To dispense that many pints, it took quite a few hours but it was heart breaking pouring it straight down the drain.”
In May, the British Beer and Pub Association (BBPA) estimated 70 million pints would be lost due to Covid-19.
Emma McClarkin, from the BBPA, said: “The need to destroy so much beer really shows how much our brewing and pub sectors have been affected by this crisis.”