Monitoring storm overflows
There are about 15,000 storm overflows in England and 1,300 of them are in our region. Find out where the storm overflows we monitor are located.
We currently monitor around 80% of storm overflows in our region, which shows when they operate and how long for, and have a programme in place to install monitoring equipment on all storm overflows by 2023.
We provide updates when our storm overflows near bathing waters operate. We also give this information to organisations, including Surfers Against Sewage and local authorities.
Visit our Storm Overflow Improvement Dashboard to find out which overflows are currently being addressed (2020-25) as well as future dates for improvements.
The impact of storm overflows
As storm overflows should only operate during periods of intense rainfall, any foul water released from them will be very dilute because of the large volumes of rainwater flowing through the sewers, so they have very little environmental impact.
The Environment Agency is responsible for river and bathing water quality and it regulates intermittent discharges from storm overflows through environmental permits. The main polluting load of the contents of a sewer should flow to the treatment centre, allowing very dilute sewage to overflow when the sewer capacity is exceeded.
When storm overflows operate, the dilute sewage contains faecal bacteria, but their operation does not mean a bathing water’s quality is necessarily unfit for swimming. Bacteria generally do not survive long outside host organisms and are especially fragile when exposed to sunlight in seawater. Learn more about factors that affect water quality.