It could be described as unseen pollution. Around 500,000 homes not connected to a public sewage network depend on septic tanks — many of which are not working properly with resultant risks to human health and the environment.
In an effort to deal with the problem, improvement grants will rise from the current €5,000 to €12,000 from January 1.
Though not nearly enough inspections are carried out by local authorities, an EPA report found that half of the septic tanks inspected failed to reach the required standards, with an additional 20% posing an immediate risk to human health and the environment.
Tanks are designed to remove pollution and release treated water to the environment. If sewage isn’t treated correctly, it can carry harmful bacteria and viruses which pose a threat to our rivers and streams.
There can also be seepage into wells used by people for drinking water. About 165,000 households have both a septic tank system and a well.
Half of Ireland’s septic tanks failed inspection in 2022. 20% were a risk to human health and the environment. 550 are not fixed more than 2 years after inspection. Read our latest report: https://t.co/1NuLvntLtu @LGMAIreland @DeptHousingIRL @EPACatchments #EPAoee #septictanks pic.twitter.com/po8zFyLVpO
— EPA Ireland (@EPAIreland) June 28, 2023
David Flynn, of EPA’s environmental enforcement office, said half of the problems are very straight-forward and require desludging a tank rather than tank replacement. The EPA is trying to increase the awareness of servicing the tank and emptying the sludge regularly.
Meanwhile, the enhanced grants can be used to repair, upgrade, or even replace poorly-functioning septic tanks, according to Senator Tim Lombard, Cork South-West.
Domestic water from toilets, sinks, showers, washing machines, and dishwashers enters the septic tank system, which is not allowed to discharge into rivers and drains.
Solids settle and form a sludge which needs to be emptied at least once a year to prevent blockage. The liquid flows from the tank into a network of shallow, underground pipes, called a percolation area.
Studies have found frequent occurrences of bacteria in groundwater and household wells, creating obvious risks for people consuming the water. Another risk to human health is created when tanks overflow and leak into the surrounding area.
When a tank system is working properly, the liquid is naturally treated as it flows through the soil. Also, there are alternatives in the absence of a suitable percolation area — soil and sand filters and constructed wetlands, for example.
Separately, the scandalous discharge of raw sewage from large urban areas into rivers and the sea has been highlighted, and it will take a "high level of sustained investment" to bring all treatment systems up to standard in the next two decades, says EPA director Dr Tom Ryan.
On a positive note, he described the elimination of raw sewage discharges from Cobh and Castletownbere, County Cork, as a good example of progress. More of the same is badly needed.