As referred to in other blog posts, there has been a growing concern about storm water overflows in England and Wales, the quantity and the frequency. Particularly where there may have been no unusual storms. Before addressing this latter point the government Department (Ministry) responsible had been working with the private companies ('DBO contractors') to consider the next phase of improvements required, costs and who pays.
Defra reports that "There are around 15,000 storm overflows in England. They discharge at different rates depending on local conditions including climate, rainfall and the type of sewerage system. In 2021, 90% of storm overflows discharged at least once, with 5% discharging more than 100 times, including in high priority nature sites such as Sites of Special Scientific Interest. Bathers and other water users are impacted by the 8% of storm overflows that discharge near a designated bathing water. "
Targets: "By 2035, water companies will have: improved all overflows discharging into or near every designated bathing water; and improved 75% of overflows discharging to high priority sites. By 2050, no storm overflows will be permitted to operate outside of unusually heavy rainfall or to cause any adverse ecological harm."
"Based on the modelled costs provided in the Impact Assessment, it is anticipated that annual water bills averaged over the whole period to 2050 would eventually rise by £42 p.a. compared to current prices. There will be no bill impacts until 2025. The modelled bill increases will start in 2025 and would average £12 between 2025 and 2030 (DEFRA Storm Overflows Discharge Reduction Plan 26 Aug 2022).
"The main costs are capital investment in equipment to contain and treat storm overflows (range in PV terms base year 2022: £25,805m to £40,746m), associated operating costs (£716m), and the cost of financing the investment (£10,023m to £15,827m). The direct impact of these costs would be on the nine regulated sewerage companies in England but would be passed to customers in their bills (DEFRA Storm overflows: Impact assessment 02 Sept 2022).
Sewerage costs indeed! A retired Thames Water engineer once commented that the worst thing ever 'invented' was combined sewerage - that is foul and storm water collected through the same pipes. Other water company folk have commented that even where the systems start off separate, over time misconnections and deliberate misconnections start to build up where individual house-owners and their builders of extensions may have simply used the nearest inspection chamber to connect to - uncaring as to whether it was designed to collect foul or rain water.