Two-thirds of Mayo septic tanks inspected last year failed
SEVENTY-ONE septic tanks were inspected in Mayo last year, with 66 per cent of them failing.
The figures have been published by the Environmental Protection Agency (EPA) in its report on domestic waste water treatment system inspections, which details the findings of septic tank inspections completed by local authorities in 2025.
Across the country, 1,466 septic tanks were inspected last year, with 59 per cent (863) failing because they were not built or maintained properly. Faulty systems pose a risk to human health from harmful bacteria and viruses through the contamination of drinking water wells, and can pollute rivers and streams through releases of nutrients such as nitrogen and phosphorus.
The local authority in Mayo was required to carry out 53 inspections last year but conducted 71, with a 66 per cent failure rate.
Systems failing in Mayo in the period 2013-2025 amount to 588, with 84 per cent of them fixed by the end of last year.
When septic tanks fail inspection, local authorities issue advisory notices to householders setting out what is required to fix the problem.
Commenting on the report, Pat Byrne, director of the EPA’s Office of Radiation Protection and Environmental Monitoring, said: “The gradual increase in the number of faulty septic tanks being fixed by homeowners since 2013 in response to failed inspections is welcomed, as these are in the areas of greatest risk to rivers and drinking water wells.
“This has been aided by increased government grant aid and greater enforcement activities by proactive local authorities. However, more consistent and sustained enforcement is needed across all local authorities to ensure that faulty septic tanks are fixed as soon as possible and that public health and the environment is protected.”
The grant schemes for remediation of septic tanks were amended in 2024 and increased from €5,000 to €12,000. There were 460 grants awarded in 2025, totalling nearly €4.77 million, up from 265 grants awarded in 2024.