The highest average bill will be as much as £759 for Southern Water customers in southern England. Water companies have come under sustained criticism in recent years amid outrage over sewage spilling into Britain’s rivers and seas. Annual water bills surged by £123 last year at the start of the five-year period. Related: Customer complaints over water bills surge by 50% in England and WalesCustomers of United Utilities in north-west England will see the biggest increase in their average annual bills – £57. However, the Consumer Council for Water (CCW), which represents consumers, said poorer households faced a “postcode lottery” because of different policies on support from different water companies.