Thames Water and Southern Water faced tough questioning by MPs on Wednesday (13/10) about water pollution.
Thames Water provides drinking water to 15.5 million customers across London and the Thames Valley.
The Reading-based firm has been fined a number of times, including a £1.8 million penalty for an incident which polluted a waterway and residential gardens, and killed almost 150 fish.
Video report on Thames Water by ITV Meridian's Penny Silvester
Thames Water's Chief Executive, Sarah Bentley was asked to explain what investment was being made to tackle sewage spills and pollution from fats, oils, chemicals and plastics.
She said: "People are genuinely concerned and upset about the quality of the rivers and the situation with sewage discharges. Monitoring river water quality more broadly, as we're doing in a trial in the Thames in Oxfordshire is something I'm really keen on doing."
Sarah Bentley, Thames Water:
Southern Water, which covers Hampshire including Winchester and Andover, was also at the meeting.
It comes after Southern Water received a £90m High Court fine for 51 offences of releasing raw sewage.
14 beaches in Thanet remain closed for a second week after wastewater was discharged into the sea from a Southern Water pumping station at Broadstairs.
Wednesday (13/10) is the 9th day that Thanet waters remain closed to swimmers and walkers below the water mark, after the unscreened sewage was released into the sea.
Daily calls are taking place between Southern Water, the Environment Agency and Thanet District Council to assess how long those restrictions will stay.
Despite some signage, lots of people ITV Meridian spoke to are unaware the restrictions are still in place.
Sea swimmer Rebecca Douglas said as restrictions enter their second week, she doesn't think Southern Water are doing enough to warn people.
She said: "People are walking up and down with their dogs, it's a site of special scientific interest and it's part of a marine protected area. All of this [sewage] is swilling around in our beautiful ocean and it's just incredibly frustrating to be subjected to this constantly."
Rebecca Douglas, sea swimmer:
The sewage release has cast a shadow of doubt over a national paddle boarding event due to take place at Broadstairs Viking Bay on Saturday (16/10).
Organisers said they are confident that will be going ahead but that the water quality should never have been in doubt.
Andy Webb, Kent Surf School said: "It should never have been at that point with Southern Water. Our water quality should be clean all year round regardless. And that was the question mark on this happening this national event. It's important to hold events like this so people can come down here and see what we can offer in Kent as a community."
Andy Webb, Kent Surf School:
Thanet residents, councillors and business are very proud of their beaches and it's not the image the area want to project.A Kent County Councillor is calling for Southern Water to hold a public meeting where people can put their concerns and questions to the company directly.
Councillor Karen Constantine, Kent County Council, Lab said: "I think you'll see demonstrations. You've seen them in Whitstable, you'll see one in Margate soon and there'll be one in Ramsgate. This is going to be the future until Southern Water clean up their act and stop discharging raw sewage into our seas."
Cllr Karen Constantine, Kent County Council, Lab:
The Chief Executive of Southern Water, Ian McAulay, was asked by Committee member Matthew Offord MP about whether operatives and senior members of the company deliberately hid documents in locked cupboards.
Ian McAulay said: "There was an instruction given to some members of staff under duress not to handover documents when an inspection occurred.
In other conversation, Ian McAulay said: "There were some deliberate acts and that's one of the reasons why I made the recommendation to the board that when it did come to court, which was this year, that we would plead guilty to all charges because we were, simple as that. Behaviours were inexcusable."
Ian McAulay, Southern Water: