The privately owned companies have apologised for the amount of contaminated water being discharged into rivers and seas, amid mounting public anger over the practice.
Some campaigners have cautiously welcomed the move, but others say firms are shifting the cost on to billpayers.
The industry paid out £1.4bn to shareholders in 2022.
Musician and environmental campaigner Feargal Sharkey called it a “half apology” that was another attempt to extract more money from customers.
“What I am actually hearing is no apology for the fact we have paid them for a service we haven’t got, they are now suggesting we pay them a second time for a service we haven’t had,” he told BBC Radio 4’s Today programme.
“We should have an apology for the suggestion they are going to put bills up by £10bn for their incompetence and their greed. This is nothing to celebrate.”