New 2023 data for sewer overflows in the Dee catchment: what does it tell us?

Recently, water companies shared their statistics showing how much raw sewage was released in England and Wales in 2023, and the numbers are shocking again. Sewage treatment works release both treated effluent and raw sewage via sewer overflows (CSOs). These overflows are supposed to be used during high rainfall events as a pressure valve to stop sewage flooding back into homes. Analysis by The Rivers Trust revealed that 98% of the known reasons for very high unacceptable levels of spills in England were due to poor management and under-investment in the sewer system, not due to exceptional weather.

Most of the sewage treatment works in the Dee are managed by Dwr Cymru, with a handful managed by United Utilities. In 2023 the data shows that raw sewage was released for 51,165 hours overall on 8,916 occasions across 274 monitored CSO’s.

To view the full dataset across England and Wales visit The Rivers Trust Sewage Map here.

Peter Powell, Welsh Dee Trust CEO, said:

“This data shows that our antiquated sewage systems are ineffective for the Dee. The sewage system requires modernising to bring it up to standard; I hope the investment plans for the 2025 to 2030 period show the required levels of investment”.

Want to help the state of our rivers? Have a look at our citizen science schemes you can get involved with! You can help monitor water quality with the aim of idfentifying and eliminating sources of pollution in your local tributary with us, or join our Smartrivers scheme that analyses river invertebrates to infer the health of the Dee’s tributaries. Head over to our Support us – Citizen Science website page to find out more.