Question to the Department for Environment, Food and Rural Affairs:

To ask Her Majesty's Government what assessment they have made of the environmental damage caused by spillages from combined sewer overflows releasing raw sewage into rivers; and what plans they have to prevent such spillages.

Combined sewers that carry surface water from roofs and roads together with sewage from homes are a common sewage system. On occasion, storm sewage discharges occur from Combined Sewer Overflows (CSOs) when the risk of sewer flooding is high and pipework capacity is exceeded. This is done to reduce the flood risk to homes and businesses. The Environment Agency (EA) has looked at the reasons for rivers not achieving good ecological status and found that about 3% of water bodies are failing due to the impact of CSOs.

To prevent spillages, between 2015 to 2020 water companies are installing monitors on up to 13,000 of the 15,000 CSOs in England. These will measure how often and for how long they operate, helping inform where improvement works may be required and providing information to the public about spills. This information has been used to help develop the environmental programme that the water companies will be implementing over the next five years. This includes further monitoring of CSOs, over 700 investigations and more than 200 schemes for environmental improvement or to reduce the spills from CSOs.