ONE in four waste-water treatment plants are discharging raw sewage into the sea and rivers without carrying out treatment, posing serious public health risks.
And more than half of all plants surveyed by an environmental watchdog are failing to treat waste water to EU standards.
A new report by the Environmental Protection Agency (EPA) has also revealed that major towns, including Bray, Clifden and Kinsale, do not treat waste to the required safety standards. The 'Urban Waste Water Discharges in Ireland' report, to be published today, found that even when multi-million euro plants were built, some local authorities were failing to monitor the water quality, despite it costing just €600 per year.
The report, which covers 2006 and 2007, analysed 370 treatment plants serving 482 villages, towns and cities with populations of over 500.
* Waste water from 192 treatment plants (51pc) did not meet the EU quality standards due to plants either not operating properly or being overloaded.
* Waste water was being discharged with either no treatment or basic treatment at 112 locations at the end of 2007.
* As of June 2009, 93 of these locations remain without treatment or with just basic treatment. In the majority of cases these discharges are to estuarine or coastal waters.
* 158 locations were required to have secondary treatment or higher by December 2005 to comply with EU law. As of June 2009, 20 did not.
* 90pc of waste water in the country received secondary treatment or better. This means that the water was biologically treated to kill dangerous bugs.
The EPA has new powers to take local authorities to court for failing to ensure standards are met. Yesterday it warned that senior managers could be held personally responsible for failed treatment plants.
"Continued investment in waste-water treatment is required, as well as a dramatic improvement by local authorities in the operation and monitoring of existing waste water treatment infrastructure," EPA Programme Manager Gerard O'Leary said yesterday.
Environment Minister John Gormley last night said the fact that 25pc of the non-compliance levels were attributed to insufficient levels of sampling was "unacceptable".
"The report highlights the need for continued investment in waste-water treatment infrastructure if we are to achieve the standards required by EU and national legislation," he said.