Thames Water made over £485 million last year.
Lib Dems demand 'Sewage Tax' to clean up rivers including the River Wey.
New analysis by the Lib Dems has revealed Britain's nine water companies made a total £2.8 billion in combined operating profits last year.
Thames Water, which dumps sewage in the River Wey, made an operating profit of £488.8 million last year. As a result of sewage dumping the River Wey is one of the worst 23% of rivers in terms of ecological and overall river health according to the Rivers Trust.