59% of Septic Tanks Failed Inspection in Ireland in 2025, EPA Report Finds

The Environmental Protection Agency’s latest Domestic Waste Water Treatment System Inspection Report has highlighted ongoing concerns around septic tank maintenance across Ireland.

According to the EPA Report, 1,466 domestic wastewater treatment systems (DWWTS) inspections were completed by local authorities during 2025, with 59% of systems failing inspection. The report stated that a significant number of these failures were identified as a risk to human health and the environment.

There are nearly half a million domestic wastewater treatment systems in Ireland, the majority of which are septic tanks.

Why are septic tanks failing inspection?

The EPA identified both operational and structural issues as the main reasons for inspection failures.

Operational issues included:

• Inadequate desludging

• Poor maintenance

• Systems not being appropriately maintained by homeowners

Structural defects included:

• Illegal discharges to ditches or streams

• Leaks

• Ponding

• Rainwater ingress

The report noted that high failure rates have remained consistent with previous years, showing that issues persist with domestic wastewater treatment systems in Ireland.

Risks to human health and the environment

According to the EPA, faulty domestic wastewater treatment systems can pose risks to both human health and the environment.

The report stated that faulty systems can contaminate drinking water wells with harmful bacteria and viruses. Wastewater may also surface in gardens or run off into ditches and streams.

The EPA also identified domestic wastewater as a significant pressure on water quality in 148 at-risk water bodies in Ireland.

Excessive releases of nitrogen and phosphorus from faulty systems can contribute to pollution in receiving waters.

Inspections targeted at higher-risk areas

The National Inspection Plan requires local authorities to complete a minimum of 1,200 inspections annually.

The EPA stated that inspections are targeted at areas where domestic wastewater treatment systems are identified as a pollution risk, including:

• Areas near rivers known to be at risk from DWWTS

• Areas where DWWTS are co-located with household drinking water wells

The inspection programme has now been running for 13 years, with approximately 14,500 inspections completed.

Local authority enforcement activity

Local authorities issue advisory notices requiring homeowners to fix systems that fail inspection.

By the end of 2025:

• 84% (6,027 out of 7,212) of systems that failed inspection between 2013 and 2025 had been fixed

• The number of advisory notices open for more than two years reduced from 523 at the end of 2024 to 442 at the end of 2025

• Legal cases increased from 66 at the end of 2024 to 88 at the end of 2025

The EPA stated that increased grants, greater enforcement by proactive local authorities, and increased regulatory oversight contributed to improvements in advisory notice closures.

The report also noted that grants for DWWTS remediation increased from €5,000 to €12,000 from the start of 2024.

What can homeowners do?

The EPA stated that homeowners should ensure their domestic wastewater treatment systems are properly built and maintained to protect family health and the environment.

Regular septic tank emptying and maintenance can help reduce sludge build-up and support system performance. Depending on household size and usage, many domestic septic tanks require emptying every 1-2 years.

Homeowners with private wells should also ensure their drinking water is tested regularly.

Common warning signs of septic tank problems

Some of the most common signs of septic tank issues can include:

• Slow-draining sinks or toilets

• Unpleasant odours around the property

• Wet or boggy ground near the septic tank or percolation area

• Gurgling drains or pipework

• Wastewater surfacing externally

Heavy rainfall and saturated ground conditions can also place additional pressure on drainage areas.

Book a septic tank inspection or service

If your septic tank has not been emptied or inspected recently, arranging maintenance early may help reduce the likelihood of more serious issues developing later.

Contact the team today to arrange domestic septic tank servicing, inspection, or repair.