Combined storm overflows are designed to release excess storm water into rivers and seas when a prolonged rainfall occurs.
This helps prevent the risk of sewage backing up, preventing homes and public spaces being flooded by allowing a controlled release.
Storm Water Overflows from sewerage systems are regulated by the EPA’s discharge authorisation regime
Irish Water are required to report on storm water overflow performance to the EPA
Over half (54%) of the combined sewage loading that arises in large urban areas in Ireland is discharged from plants that are not meeting the mandatory European Union standards.
“In practice, many combined sewers are now carrying considerably more load than they were designed for and overflow in relatively minor rainfall events. The overflow of, admittedly dilute, foul sewage to a watercourse has obvious pollution implications“
Not much on EPA or IW websites in relation to CSOs