On March 27, 2025, water companies released their 2024 storm overflow data, showing only a slight improvement from 2023. Welsh Water recorded 112,589 spills over 929,168 hours, compared to 121,422 spills in the previous year. While heavy rainfall remains a key factor, wastewater treatment failures are an increasing concern.
Analysis by Afonydd Cymru found that the worst-overflowing sites were legally compliant only 1% of the time. In 2024, 276 locations spilled for over 1,000 hours, significantly impacting Welsh rivers, including the River Dee. Spills into the Dee and its tributaries threaten water quality, wildlife, and recreational use, raising concerns for both local communities and conservation efforts.
The National Environment Programme (NEP) outlines Welsh Water’s investment plans, with 33 projects addressing treatment failures, 60% due by 2027. While real-time discharge data could drive improvements, urgent action is needed to restore Welsh Water’s environmental performance and better protect the River Dee and other vital waterways.
Afonydd Cymru full report and interactive maps: https://afonyddcymru.org/welsh-water-publish-2024-storm-overflow-data-2/
Dŵr Cymru Welsh Water (2025) Storm overflow data 2024. Available at: https://corporate.dwrcymru.com/en/news-media/2024/welsh-water-launches-storm-overflow-map (Accessed: 28/03/2025).
Afonydd Cymru (2025) Analysis of Welsh Water storm overflow data 2024. Available at: https://afonyddcymru.org/welsh-water-publish-2024-storm-overflow-data-2/ (Accessed: 28/03/2025)
