But why are mercedes still feeling the heat? raw sewage was discharged into england s rivers nearly 375,000 times by water companies last year, according to the environment agency. the government has announced plans to overhaul the sewer system to tackle the problem and has promised a 40% reduction in discharges by 2040. but in west sussex some volunteers, frustrated by the high levels of pollution, have been taking samples from the waterways near their homes to find outjust how much sewage and other chemicals are in the water. zoe conway has been to find out more. chichester harbour, an area of outstanding natural beauty. people here may love being on the water, but many worry about what could be in it.