Sewage pollution is released into rivers through Combined Sewer Overflows (CSOs).
CSOs are emergency infrastructure systems that are permitted to discharge untreated waste water during periods of heavy rain. They are an important part of our sewage infrastructure and designed to stop sewage backing up into our homes during extreme rainfall events.
Water companies routinely use CSOs to release sewage into rivers, even after dry weather. They do this because they have failed to invest in the necessary sewage infrastructure to keep pace with population growth and climate change.
On top of this, regulators are failing to enforce existing legislation. In the rare cases where there are financial penalties, these are easily built into ‘operating costs’ and do not reflect the true environmental damage caused.
Water companies have no incentive to change their environmentally damaging behaviour.
Across the UK, untreated sewage is discharged into rivers daily.
3.6
millionHours worth of untreated sewage was released into rivers and seas in 2023.
464,056
Discharges of untreated sewage into UK rivers in 2023.
75
billionProfits water companies have made since privatisation.
In 2024, 54% of English waterbodies failed their ecological targets because of sewage and wastewater discharged by water companies.
Sewage contains high volumes of nitrogen and phosphorus. In excess, these nutrients can stimulate the growth of algae which starves freshwater species of oxygen. In turn this disrupts natural food chains.
Water companies need to invest in sewage infrastructure that is fit for purpose. This should not be at the expense of the customer.
Water companies need to end the routine use of CSOs.
Environmental regulators need the resources and funding to enforce current legalisation and hold polluters to account.
Polluters must pay penalties that reflect the true environmental damage being caused.
Independent, continuous monitoring of sewage discharge should be mandatory.
Water companies should not be allowed to monitor themselves as they do currently. This is known as operator self-monitoring.
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