Q&A: Storm overflows discharge reduction plan

To prevent sewers from becoming overwhelmed when the system is unable to cope with a surge in volumes of water, combined sewer overflows (CSOs) or storm overflows are permitted. When in operation, storm overflows discharge raw untreated sewage (although significantly diluted) into waterways and the sea.

There are around 14,500 storm overflows in England. The Environment Agency’s 2021 data shows that there were:

• 24,800 discharges into bathing waters with a total duration of 162,000 hours
• 28,700 discharges into shellfish waters with a total duration of just over 200,000 hours.

On 26 August 2022, the Government published its storm overflows reduction plan as a legal requirement of the Environment Act 2021. This followed a consultation on the plan which ran from 31 March 2022 to 12 May 2022.

The plan sets out actions for water companies, the Government and the public to take to help reduce the impact of storm overflow discharges.

Two of the headline targets set out in the plan are:

• by 2035, water companies will have to improve all storm overflows discharging into or near every designated bathing water; and improve 75% of overflows discharging into high priority nature sites
• by 2050, this will apply to all remaining storm overflows covered by our targets, regardless of location

The Government has called the plan “the most significant investment and delivery programme ever undertaken by water companies to protect people and the environment.” However, the Rivers Trust hihglighted that the plan “has not taken into account the thousands of responses to the draft consultation” and criticised “the government’s lack of ambition and clarity for the sector”. Water UK, the industry body representing the water sector, called the plan a “step forward” but called on the Government to do more to prevent housing developers adding to the burden on sewers.