Significant Reduction in Sewage Spills in 2025
Water companies released raw sewage into England's rivers and seas for 48% fewer hours in 2025 compared with the previous year, according to data from the Environment Agency.
The regulator attributed most of this improvement to drier weather conditions rather than upgrades to infrastructure.
Causes of Sewage Spills and Impact of Weather
Sewage spills typically occur during rainfall events to prevent the sewage system from becoming overwhelmed and backing up into residential properties. Consequently, with reduced rainfall, there are fewer instances of sewage releases.
Environmental charities have stated that the lower spill numbers do not represent genuine progress, while the industry body Water UK contends that the country is beginning to observe the effects of companies tripling their investment in infrastructure.
In 2025, sewage was spilled for 1.9 million hours, down from 3.6 million hours in 2024.
Challenges of England's Combined Sewage Network
England, like the rest of the UK, operates a combined sewage network where both rainwater and sewage enter the same system. The ageing infrastructure, coupled with population growth and increasingly intense rainfall events driven by climate change, has placed significant pressure on this system.
Rainfall in 2025 was 24% lower than the previous year, as the country experienced one of its driest starts to the year, despite heavy rain during the winter months.
Perspectives from Environmental Groups and Industry
James Wallace, CEO of charity River Action, said: "After one of the driest summers in decades, lower spill numbers were inevitable, not evidence of real change.
Water companies are still profiting from pollution, and regulators have failed to act."
Determining the exact contribution of reduced rainfall to the decline in sewage spills is complex, as it depends on both the frequency of spillages and the intensity of rainfall events.
The Environment Agency emphasized that sustained investment is necessary to achieve lasting improvements.
Water UK, the industry body, stated that the country was already "starting to see the effect of a tripling of water company investment."
In 2024, the industry regulator Ofwat approved increases in water bills in England and Wales over the next five years to fund £104 billion in infrastructure upgrades.
Infrastructure Upgrades and Government Response
Water UK highlighted the efforts of United Utilities, which upgraded more than 400 storm overflows in its service area during 2024.
Water minister Emma Hardy commented: "It is good to see that storm overflow spills are down since the previous year, but there is still an unacceptable amount of sewage entering our waterways and a long way to go in cleaning up our rivers, lakes and seas."
Health and Environmental Risks of Sewage Pollution
In 2024, leading scientists including Professor Chris Whitty, chief medical officer for England, published a report warning that sewage entering waterways poses risks to public health.
Sewage pollution also presents significant environmental hazards. It increases nutrient levels in water, leading to algal blooms that deplete oxygen and harm aquatic wildlife such as fish. Additionally, these spills introduce waste materials including plastics and pharmaceuticals into rivers and seas.
