Raw sewage is being pumped into many rivers and streams around the State because treatment facilities are unable to cope with the high levels of development taking place, a new report has warned.
The report, by the Environmental Protection Agency (EPA), found that, at the end of 2005, only one in five waste treatment plants in small towns was treating sewage to adequate standards. Less than 40 per cent of medium-sized facilities complied with minimum standards.
This is despite investment in water facilities running into billions of euro in the past decade.
Yesterday the EPA said it believed many waste water treatment plants were under increasing pressure from the development that has taken place throughout the State in recent years. It said the operation management of such plants was "proving to be a significant difficulty for many local authorities".
EPA programme manager Dr Matt Crowe said councils needed to "fast-track planned improvement works and enhanced operational controls to protect the quality of our waters".
"While the EPA acknowledge the scale of work being carried out by local authorities, we are disappointed that the necessary improvements are not happening at a fast enough pace. This is an area that needs attention."
Dr Crowe said the pressure on plants had led to the use of rain-water drains to "discharge untreated and unscreened sewage and industrial waste water into receiving waters".
"The EPA is concerned about this development and wants to see it addressed by local authorities as a priority," he added.
More than 80 per cent of waste water went through secondary treatment, compared to 67 per cent in 2003, the report found.
However, it also said there were inadequate treatment facilities in 30 large towns, cities and suburbs. Ten of these were required by law to have had secondary treatment facilities by December 2000, but this had not happened. These include parts of Howth, Baldoyle and Portmarnock in Dublin, Killybegs in Donegal, Sligo town, Tramore and Waterford city.
It also said the monitoring of discharges from treatment plants was "in need of improvement".