A third of all septic tanks in Longford failed local authority inspections last year, writes Liam Cosgrove.
Figures released by the Environmental Protection Agency (EPA) revealed 33 per cent of all tanks examined in 2014 failed to meet minimum standards.
Though only 18 inspections were carried out last year, Longfordâ€™s failure rate was 15 per cent below the 48 per cent national average.
Neighbouring counties Roscommon, Cavan, and Leitrim fared even worse with failure rates ranging between 72 per cent and 56 per cent.
Twenty-nine directions were also issued by the EPA last year, with six of those linked to supplies in Roscommon.
Westmeath, meanwhile, experienced a more modest 20 per cent failure rate.
The study also found that tanks located within close proximity of private wells are most in danger of failing to meet safety guidelines.
Of the 987 inspections undertaken, more than half of all failures occurred as a result of tanks not being desludged.
New laws introduced in 2013 require county councils to inspect tanks in order to ensure they are not carrying any risk to human health and the environment.
The EPA said that by last December the number of systems passing the inspections had increased to 76 per cent after homeowners took steps to address failures, including de-sludging, which was the most common reason for a failed inspection.
In its annual review, the agency said there was room for significant improvement if wastewater supplies are to meet European Union requirements.
â€œThose supplies with inadequate treatment for cryptosporidium are most at risk of water restrictions,â€ it said.
â€œFurther water improvements are also required because of recent, more stringent standards for lead.â€