Description: This Event Duration Monitoring dataset relates to overflow performance in England and Wales. Water and Sewerage Companies (WaSCs) submit this regulatory return annually to the Environment Agency or Natural Resources Wales to meet discharge conditions outlined in the Environmental Permitting Regulations. The English data were downloaded from environment.data.gov.uk (accessed 27th March 2025). Sewer Storm Overflow EDM Annual Returns Data for Wales were downloaded from the Dŵr Cymru/ Welsh Water and Hafren Dyfrdwy websites. For England, the dataset also includes reasons why event duration monitors may have provided information for <90% of the relevant return period, and why an overflow may have high spill counts in that period. What doesn't this dataset show?There are a significant but unknown number of overflows which are not included in this dataset because the WASCs and the Environment Agency don't know where they are within the sewer network. If you spot signs of sewage pollution please report this to the Environment Agency on 0800 80 70 60 or Natural Resources Wales on 0300 065 3000 so that these unmapped discharges can be pinpointed. Emergency overflows in England and Wales are not included in this dataset as the Environment Agency and Natural Resources Wales only require storm overflows to be included in the EDM returns, though some WASCs do record this information. Emergency overflows do have permits but these are for use in the event of mechanical issues, for example pump failure. We do publish the emergency overflows for England and Wales in the consented discharges dataset, but we don't have spill duration data for them. You can find out more about environmental permits for storm and emergency overflows for England here and Wales here. Quality ControlThe Rivers Trust has endeavoured to clean, check and interpret the data, but cannot be held responsible for any missing or inaccurate data. Points in the sea may be long-sea outfalls or they may be errors in the data. Water companies, citizen scientists and map users are welcome to contact us to notify any known data errors on specific overflows and we will flag these in the map popups and pass on to the regulators. We are providing feedback to the Defra storm overflows taskforce about how to improve transparency around sewer storm overflows, and would welcome feedback and suggestions.Contact us at data@theriverstrust.org
edmNumberofYearsOperational (type: esriFieldTypeInteger, alias: EDM Number of Years Operational, SQL Type: sqlTypeOther, nullable: true, editable: true)
noFullYearsEDMData (type: esriFieldTypeString, alias: Number of Full Years of EDM Data, SQL Type: sqlTypeOther, length: 8000, nullable: true, editable: true)