The Lewes Green Party councillors concerned about water leaks may be reassured to learn that the government, despite its other preoccupations, is well ahead of them.
South East Water has recently had its 2019 Water Resources Management Plan approved, covering water supply to their part of Lewes District for the period up to 2080. It does include provision of a new reservoir at Arlington in the 2030s. However, the main thrust, at government insistence, is on investment in improved water efficiency and preventing leakage. Reducing leakage is actually a more expensive way of increasing water supply than providing new reservoirs.
Such investment will have to be paid for, and it is future customers who will have to cover the cost.