A discharge licence is required where a trade effluent is discharged to either a public sewer, surface water or groundwater.
The Water Pollution Act (1977) defined a trade effluent as a wastewater, which is discharged from premises used for carrying on any trade or industry (including mining) but does not include domestic sewage or storm water.
- All trade effluent discharges must be licensed by either Irish Water or the local authority.
- Discharges of domestic-type wastewater (sewage) from commercial and industrial premises to municipal sewers is generally not subject to licence but a licence would be required if the discharge is directly to a surface water.
- Discharges of other-type wastewater (eg. canteen, process water, commercial floor cleaning etc.) from commercial and industrial premises is normally subject to licence to for discharges to either sewer or surface water.
- A licence is typically not required for domestic sewage not exceeding a volume of 5m3 in any period of 24 hours that is discharged to an aquifer from a septic tank or other disposal unit by means of a percolation area, soakage pit or other method.
- A licence is required for discharge of domestic sewage from a septic tank where the discharge is direct to surface waters and, in all cases where the discharge exceeds 5m3 in 24 hours.
- Many industrial processes do not generate process wastewater or effluent but may discharge other waters, eg. cooling water, boiler make-up or blow-down water. These would be regarded as trade effluent and as such should be licensed.