The company, which was prosecuted by the Environmental Protection Agency (EPA), pleaded guilty at Dublin District Court to 11 charges, in four cases, under Waste Water Discharge (Authorisation). The prosecutions related to water treatment plants in Dublin, Limerick, Galway and Cork.
Irish Water had been prosecuted twice previously by the EPA and could have faced fines of up to €5,000 per charge.
Finalising the case yesterday, Judge John Brennan said that save for one of the facilities, in Balbriggan, in Co Dublin, all the plants were antiquated while Irish Water came into being relatively recently. He also noted its co-operation with the EPA, that it had agreed to discharge prosecution costs, and the lack of risk to public health.
At an earlier hearing, prosecuting solicitor Maeve Larkin said the EPA was proceeding with three charges in connection with a waste water treatment plant in Athenry, Co Galway. This facility takes in waste water for treatment and then discharges clean water into the Clarinbridge River.
Irish Water failed to complete required upgrades by the end of 2015 and had released water with excessive pollutants into the river and failed to report an incident.
Mr Cole asked the court to note that Irish Water intends to carry to out a €5m upgrade at the Athenry plant. Judge Brennan imposed fines totalling €3,500 in this prosecution.
The next case involved four charges related to sewage overflowing at three waste water pump stations in Balbriggan, in north Co Dublin last year. These led to a minor fish kill in a river in May, and Skerries beach being closed for the June bank holiday weekend.
The EPA learned about the beach closure from media reports and it had not been reported to them by Irish Water as required, said EPA inspector Brendan Kissane.
“‘Do not swim’ notices had to be put up”, he told the court.
Fines totalling €5,000 were imposed for the pollution incidents in Balbriggan.
The next case related to two offences at a waste water treatment plant in Boherbue, Co Cork. EPA inspector Patrick Chang said upgrade work was required by the EPA to be completed by the end of 2014 but it is not going to happen until 2019.
Discharges to the Brogeen River, which leads to a tributary of the Blackwater, contained pollutants which were toxic to fish and could affect salmon reproduction.
However, he agreed with defence counsel that there was no danger to public health and significant upgrades are planned. Judge Brennan fined Irish Water €4,000 for these breaches of the regulations.
Ms Larkin said the last case related to two offences at Dromcolliher, Co Limerick, at a 1940s-built water treatment plant.
Judge Brennan imposed fines amounting to €7,000 in this case.
The guilty plea in all the prosecutions meant a trial as long as a tribunal had been avoided, the judge had remarked at an earlier stage.