Raw sewage contains a cocktail of bacteria, viruses, harmful chemicals, and microplastics. This is a disaster for our ocean.

Storm overflows

Sewage Pipe

Credit: David Dixon

What is a storm overflow?

Many of our sewer pipes collect both rainwater and sewage (called combined sewers). Safety valves, called Combined Sewer Overflows (CSOs, or just storm overflows) were built into them to stop flooding during periods of very heavy rainfall. These storm overflows allow untreated sewage to spill into our rivers, estuaries and seas.

What's the problem?

Water companies across England have become too reliant on using storm overflows to dump raw sewage in our waters, rather than improve their infrastructure.

The raw sewage contains a cocktail of bacteria, viruses, harmful chemicals such as Per- and polyfluorinated alkyl substances (PFAS), and microplastics. It’s nearly impossible to remove microplastics and ‘forever chemicals’ once in the environment where they continue to build up and put wildlife, people and planet at risk.

How sewage pollution impacts our ocean

Currently, sewage is being dumped not only into bathing waters and rivers, but also into supposedly protected areas of English coastline.

In 2021, 1,651 storm overflows within 1km of a Marine Protected Area (MPA) in England spilt untreated sewage for a total of 263,654 hours - equivalent to over 30 years - across England.

These protected areas are home to vital habitats like seagrass and chalk reef, as well as an incredible array of marine life. By allowing pollutants to continue pouring into our seas, our ocean is being put at greater risk.

What the data tells us


storm overflows within 1km of an MPA in England


of these overflows spilt more than 10 times in 2021

According to the Department for Environment, Food & Rural Affair’s (Defra's) own latest assessments, only 19% of estuaries and 45% of coastal waters are at Good Ecological Status, with none meeting ‘good’ Chemical status, and three quarters (75%) of shellfish waters failing to meet water quality standards.

Snakelocks Anemone on Seagrass Georgie Bull

Seagrass is an important habitat for wildlife, and the planet, being put at risk from sewage pollution.

Credit: Georgie Bull

Our work so far

In early 2022, Defra consulted on Storm Overflows Discharge Reduction Plan which we hoped would finally address the cocktail of contaminants that we know are regularly discharged into our rivers, estuaries and seas from storm overflows in England. We welcomed the UK Government’s ambition to reduce the harm from storm overflows as a priority and agreed that water companies' reliance on overflows is unacceptable.

However, the outlined plan failed to protect estuaries and coastal waters by completely excluding around 600 storm overflows in the long-term, which would continue to dump uncontrolled amounts of sewage directly into our seas and onto our beaches.

While these overflows may not be adjacent to sites designated as bathing waters, they could still be discharging onto other beaches people use for walking, swimming and surfing, as well as into shellfish waters and some MPAs.

On 18th August 2022, we wrote an open letter to Defra, outlining the ways in which the Storm Overflows Discharge Reduction Plan is failing.

Sewage in the sea

Credit: Shutterstock: Andrei Metelev

In late August 2022, DEFRA published it's final Storm Overflows Discharge Reduction Plan, giving water company bosses until 2050 to improve England’s storm overflows to prevent or reduce mass-scale sewage discharges.

The plan hasn't been amended since the consultation: it lacks the ambition needed to protect estuaries and coastal waters, and the pace of delivery for all targets is far too slow. The concerns we raised in our response to the consultation and in our open letter to Defra still remain.

Giving the green light to this form of environmental vandalism for decades to come will do untold damage. We believe the Government’s lack of urgency is not only dangerous but also unlawful.

We're bringing an action for judicial review against the Secretary of State for the Environment, Food and Rural Affairs for not taking effective action on sewage pollution that is entering our seas.

We hope that the legal case will compel DEFRA to rewrite its Storm Overflows Discharge Reduction Plan 2022 to impose tighter deadlines on water companies, and effectively apply to coastal waters, which are almost entirely excluded at the moment.

Raw sewage is being pumped into our seas for hundreds of thousands of hours each year; into bathing waters and supposedly protected areas. It's putting people, planet and wildlife at risk.

Sewage shutterstock_2135758211 Olga Pedan

Credit: Shutterstock | Olga Pedan

Public support

We're angry about how often raw sewage is dumped into our sea. So are our supporters. As the UK's leading marine conservation charity, we need to be the voice for our ocean now more than ever.

If you want to support our work, please do make a donation, or become a member. Every single action you take to support us makes a difference – and we are incredibly grateful.

The quotes above were collected in an anonymous survey we conducted on social media platforms, to better understand public views and values regarding marine habitat restoration in Sussex. We did not ask about sewage specifically – all the responses we received around sewage were completely unprompted.

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Healthier oceans, protected oceans