The Great UK Water Blitz is back from 19 to 22 September, and sign-ups for monitoring water quality in our waterways are now open.
Back in April 2025, nearly 8,000 people tested the water quality of their local rivers, lakes, ponds or streams. The results showed that 66% of freshwater sites in the UK had poor ecological health. By taking part in the September WaterBlitz, you’ll be helping us collect even more valuable data, building a picture of water health across the UK.
Water Blitz project is especially important as the Environment Agency struggle with real-term funding reductions. As they had to pause their testing.
Serious pollution incidents by water companies have risen 60% in a year, according to the Environment Agency. In total there were 2,801 pollution incidents in England in 2024. This is the highest on record, compared with 2,174 in 2023. Just three companies were responsible for the vast majority of the most serious incidents. This includes our own London Thames Water (33), Southern Water (15) and Yorkshire Water (13).
Thames Water levels of serious pollution doubled. Plus they were the worst performer for reporting pollution events to the regulator.
Why the increase in pollution?
England uses a combined sewage system which means both rainfall and sewage are processed through the same system. Last year, rainfall levels were up, which could have overwhelmed some water company infrastructure. However, despite variations in rainfall, discharges that result in serious pollution are a breach of their permits and legal obligations.
Wastewater is usually sent to a sewage treatment works. However, capacity can sometimes be exceeded during heavy rainfall, especially if dry ground cannot absorb large quantities of water. This could lead to inundation of sewage works and potential flooding of homes, roads and open spaces.
The system is therefore designed to overflow occasionally, and discharge excess wastewater into the sea and rivers from combined sewer overflows, external. For more info see How much sewage is spilled near you?.
Sign up to help monitor for Water Blitz
Sign up today to get your free water testing kit 🔗 https://earthwatch.pulse.ly/t7bc4gdxph
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