The EPA (Environmental Protection Agency) figures show that over half of septic tanks inspected failed. The EPA has recently published the third National Inspection Plan 2018-2021: Domestic Waste Water Treatment Systems Draft for Consultation which covers a four year period. The National Inspection Plan is implemented by Local Authorities under the supervision of the EPA, however the EPA also said that the majority of cases of failure was because the tank was not de-sludged or not properly operated and maintained.
The regulations (S.I. No. 223 of 2012) governing the operation and maintenance of domestic wastewater treatment systems (DWWTSs) require owners of DWWTS to operate and maintain their systems and this includes de-sludging. All domestic wastewater treatment systems require ongoing maintenance to ensure that the septic tank/treatment system operates effectively and that solids do not enter the percolation area and clog the distribution pipe work.
The inspections allow for the systematic collection of information on the condition of domestic waste water treatment systems in Ireland. The results show that many of the failures could have been prevented. The EPA published the first national inspection plan in 2013 with the second plan following in 2015.