The project by University College Dublin and funded by the Environmental Protection Agency sought to establish what factors cause the delay of maintenance of their on-site septic tank systems.
It also examined how communication aimed at improving maintenance could be more effectively delivered to households.
“Septic tank systems operating ineffectively are a source of pollution to our water resources and generate significant risks to public health,” said project leader Eoin O’Neill.
Dr O’Neill said private well-owners who have an individual septic tank system on their property are exposed to higher health risks.
“We know that about 30% of private wells in Ireland are contaminated by E.coli. It is important that this health and environmental risk is communicated to the large number of Irish households that rely on a septic tank system so they are motivated to undertake regular maintenance of their system,” he said.
Unwittingly consuming polluted water from private water sources is identified as being a dominant factor in the transmission of E.coli, particularly verotoxigenic E.coli, a strain of the bacteria which has the potential to cause lifelong kidney problems.
Catherine Devitt, project researcher, said the study showed that people do not realise the dangers of an un-serviced septic tank.
“We found that people are often only alerted to their septic system when it turns into an inconvenience for them — such as when there is a strong odour, or unsightly ponding in the garden,” she said.
“At this point, water contamination may have already occurred. There is the problem of “out-of-sight, out-of-mind.”
The Environmental Protection Agency has also welcomed the findings of the report. “We would encourage people to have the sludge emptied from their tank on a regular basis using a permitted contractor, and if they have a package treatment system to have it regularly serviced,” Margaret Keegan of the EPA said.
“These measures help address the risk of well water being contaminated by septic tanks and reduce the likelihood of illness associated with contaminated private wells.”
“The challenge for those striving to improve environmental and health outcomes through regulation is to identify an appropriate balance between enforcement, incentives and education so as to maximise positive long-term behaviour changes, the guidelines produced by this study seek to address this balance,” she said.