Potentially illegal practices
Sewage overflows were designed and intended to be an ‘emergency release valve’ only to operate in ‘exceptional rainfall events’ to reduce pressure on the sewage system to avoid sewage backing up into our homes. The Urban Waste Water Treatment Regulations only permit sewage overflows to operate in ‘unusually heavy rainfall’. However, the government has admitted sewage overflows “are being used significantly beyond their original purpose”.29
Water companies are prohibited from making ‘dry spills’ from sewage overflows when there has been no rainfall. However, with water companies now allowed to self-report and with little clarity on what is classed an ‘extreme rainfall event’ it’s unclear just how many ‘dry spills’ are happening and how much sewage is potentially being illegally discharged. So, we’ve been investigating where there have been discharges but no significant rainfall to indicate where sewage overflows are being used when they shouldn’t be. We’ve collated rainfall data provided by the Met Office from over 150 locations across England and Wales and linked the 455 locations on our Safer Seas & River Service (SSRS) to the nearest available data source to determine rainfall. We’ve then looked at the sewage discharge notifications issued for each of these locations and if there had been any rainfall in the  days preceding the discharge notification. Where we had seen a discharge notification but no rainfall in the preceding  days, we have assumed this to be a ‘dry spill’.
Take a look at the map below to investigate where we have found water companies to be making ‘dry spills’ over the last year – that’s raw sewage entering our waterways when there has been no rain.