Across much of the UK, our sewerage network is set up as a ‘combined system’. This means that our sewage water and surface water flow into the same pipe system before travelling to a treatment plant. However, when the sewerage system becomes overloaded – because of heavy rainfall for example – water companies are allowed to use sewage overflows (including Combined Sewer Overflows (CSOs) and pumping stations) to discharge untreated human sewage and waste water into the environment.
Sewage overflows are meant to act as an emergency relief valve for our sewerage system to stop sewage backing up into our homes. Legislation states they should only be used in ‘exceptional circumstances’.
Despite this, we’re seeing hundreds of thousands of discharges happening every year. In 2021 alone, water companies discharged sewage into rivers and seas over 370,000 times. That’s an eye-watering 2.7 million hours of sewage swamping our beaches and river banks.
And that’s just the discharges that water companies tell us about. At SAS we’ve become increasingly concerned that discharges are being used to regularly dispose of untreated sewage, even during times of low rainfall – or none at all. Our Safer Seas and Rivers Service notified users of over 5,550 sewage discharges affecting bathing waters over a 12 month period in 2021. Read the full results in our Water Quality Report.
Our friends at Windrush Against Sewage Pollution have been investing this further and have uncovered thousands of cases where water companies have discharged sewage illegally during dry periods, or before a treatment plant has reached its minimum treatment rate. In 2021 Southern Water were fined a record £90 million for deliberately dumping sewage into waterways between 2010 and 2015. And in the same year the environment agency and Ofwat launched an investigation into over 2,000 sewage treatment works across six water companies for releasing unpermitted sewage discharges into watercourses.
All this sewage entering the environment is wreaking havoc on our precious environment, and putting our health at risk. Check out how storm overflows are making us sick.
There are around 22,000 sewage overflows in the UK (excluding Scotland). Sometimes they take the form of very obvious pipes going straight out to sea, or large grates opening onto beaches, but most are well-hidden, out of sight of unsuspecting eyes.
See if your local swim or surf spot is being swamped in sewage pollution from storm overflows, in real time.
We won’t be able to get rid of storm overflows overnight. But there are lots of ways we can reduce our reliance on them. We can:
Check out our demands and take action with us.
