More than half of septic tanks inspected in Sligo and Leitrim have failed tests.
In Donegal, just under a third of septic tank inspections resulted in failures.
The Environmental Protection Agency has today released a review of more than 2,000 inspections of septic tanks and other domestic wastewater treatment systems in 2017 and 2018.
Nearly half of the systems failed inspection because they were not built or maintained properly.
In Donegal in 2017/2018, there were 230 inspections, with 29% failing.
In Sligo, there were 83 inspections, with a 54% failure rate.
In Leitrim, there were 56 inspections, with a 63% failure rate, which is among the highest in the country.
The EPA says householders need to fix these systems.
For systems failing between 2013 and 2018, 77% were fixed in Donegal, 67% in Sligo and 37% in Leitrim.
Noel Byrne, senior scientist in the EPA’s Office of Environmental Enforcement, says the government’s proposed expanded septic tank grant scheme, duie to be launched later this year, will increase the maximum grant aid available to €5,000, and remove means test requirements.
