The EPA has published its latest report into domestic wastewater treatment systems like septic tanks, and have found that nationally half failed the inspection, and almost 30% pose a danger to both human and environmental health. There are nearly half a million domestic wastewater treatment systems in Ireland, mostly septic tanks. 

In Tipperary of the 62 systems inspected, which was the minimum requirement, 34% of them failed. Since 2013, that local authority has fixed 60% of the faults found which is the third lowest improvement rate in the country.

In Waterford, 6 of the 20 systems inspected did not pass. Only the minimum number required were tested and since 2013, Waterford County Council has overseen the fixing of 61% of the failing systems.

Limerick City and County Council was required to test 33 systems in 2021 but actually tested 46, and had a failure rate of 43%. Since 2013, they have fixed 87% of identified failures.

Cork County Council were required to inspect 60 systems but actually completed 62 tests. The failure rate of these 62 was 60%. The local authority here has fixed 86% of identified failing systems since 2013.


Failing domestic wastewater treatment systems can contaminate household wells with harmful bacteria and viruses if not built and operated properly. Excessive releases of nitrogen and phosphorus can also cause pollution in rivers and other waters.

The draft River Basin Management Plan for Ireland has identified domestic waste water as a significant pressure on water quality in 188 rivers and other waters nationally

The EPA say that the failure to resolve older issues is an increasing concern. 533 systems that failed the inspection have not been fixed after two years. The environmental body stated that local authorities need to increase their enforcement to get the public to fix any identified issues. Since 2013, seven local authorities have taken 36 legal actions for failures to fix domestic wastewater treatment systems.

Noel Byrne, EPA Programme Manager, said that the need to fix failing septic tanks has been repeatedly highlighted by the EPA as a concern.

“It is unacceptable that over 500 failed septic tanks are not fixed more than two years after inspection. Over half of these involve sewage ponding in gardens and discharging to ditches and streams, which cannot be allowed to continue. Local authorities must increase their enforcement effort to ensure failed systems are fixed.”