'Risk to human health' - warning from EPA as almost half of septic tanks failed inspections

Nearly half of all septic tanks tested in Ireland in 2023 failed inspections, according to a report by the Environmental Protection Agency (EPA).

According to the EPA report, 45% of Domestic Waste Water Treatment Systems (DWWTS) inspected in 2023 failed, with the EPA saying this poses “a risk to human health and the environment”. A total of 1,189 DWWTS inspections were completed by local authorities last year, of which 532 failed.

Domestic waste water treatment systems (DWWTS), mostly septic tanks, are used by householders to treat sewage. There are nearly half a million systems in Ireland, with around 1,200 being inspected annually.

Reasons for failures were in two categories; Operational (de-sludging and maintenance), or structural defects (illegal discharges to ditches/streams, leaks, ponding and rainwater ingress).

Local authorities issue advisory notices requiring householders to fix tanks that fail inspection.

The EPA report found that there were 576 cases where issues notified to householders over two years previously had still not been addressed.

However, 80 per cent of tanks that failed inspections between 2013 and 2023 were fixed by the end of last year, representing an ongoing improvement from 75 per cent in 2021 and 78 per cent in 2022.

Counties with significant numbers of failures combined with a low level of resolution are Waterford, Roscommon and Kilkenny.