Storm overflows

Storm overflows

We are aware of our customers' increasing concern about the effect storm overflows have on our rivers and the sea.

In an ideal world we wouldn’t have storm overflows at all – they are a legacy from the past. They have always been part of the sewerage network in the UK because the majority of sewers carry both rainwater and foul sewage and they prevent properties from flooding following intense rainfall. We are now getting more intense rainfall due to climate change, which can affect when overflows operate. Storm overflows have minimal or no ecological impact because what is released is diluted wastewater.

Although overflows are permitted by the Environment Agency, we agree that they have no place in the 21st century, but it will take time and significant investment to progressively eliminate them.

We are committed to completely eliminating the discharge of untreated sewage, starting with storm overflows that discharge most frequently and those that have any environmental impact. Our Storm Overflows Improvement Plan means we are taking the following actions:

  • Investing £3 million a month to tackle storm overflows, with work already underway.
  • Sewage treatment upgrades at 42 water recycling centres to increase capacity and with more nature-based, low carbon methods introduced.
  • A 25% reduction in the number of hours of storm overflow discharges by 2025.
  • Increased environmental and public health monitoring at key locations.
  • Use of artificial intelligence to manage sewerage network and provide real time bathing water information.

On this page you can find more information about what storm overflows are, how they work and their environmental impact. We also outline what we’re doing to improve the system and how you can help us to eliminate any negative impact that could be caused by storm overflows.

The background

The impact

The next steps