The European Court of Justice has found Ireland is in breach of an EU directive on the provision of waste water treatment plants.
Ireland was found guilty of failing to provide secondary waste-water treatment plants in towns with populations more than 15,000, in line with the relevant directive.
The court found that Ireland had failed to carry out secondary treatment of waste water at six locations: Bray, Howth, Shanganagh, Letterkenny, Sligo and Tramore.
The ruling (read it in full) by three judges at the court in Luxembourg found Ireland was in breach of the 1991 Urban Waste Water Treatment Directive.
Ireland was ordered to pay the costs of the case.
Action was first taken against Ireland in July 2004 by the European Commission.
Following correspondence between the commission and the Government the case was finally taken by Brussels to the Court of Justice in July 2006.
Ireland warned to comply
Ireland has effectively been told to comply with the directive, and it is now up to the European Commission to monitor progress.
If the commission feels that Ireland has not complied then a second case can be brought which could result in fines.
The thrust of Ireland's defence was that plans to provide this infrastructure are being advanced as quickly as possible and there is a commitment to tackle the problem.
Ireland did not contest the fact that it had failed to comply with the directive in relation to five of the areas.
In relation to Howth, the court found that Ireland's argument that the agglomeration should be redefined could not be accepted.
It said Ireland had produced no evidence that the area from which the waste water originated should no longer be part of the Howth agglomeration.
The ruling opens up the possibility of heavy fines being imposed but Ireland is being given time to correct the breaches.
Minister for the Environment John Gormley has already announced a series of measures to improve drinking water, following a separate ECJ ruling.
