Individual Dwelling Wastewater Discharges

What’s the issue?

There are almost half a million septic tanks in the country. Also known as On-site Domestic Waste Water Treatment Systems (DWWTS), these are the individual sewage treatment systems attached to one-off houses in rural areas. Discharge from a septic tank contains human excrement as well as household detergents and anything else commonly flushed down a toilet or sink. 

If not properly treated, discharges from septic tanks can pose a serious risk to the local environment, especially to vulnerable high status water bodies and in catchments with unsuitable soil conditions.  Household wells can also be at significant risk of contamination often from their own septic tank.

The EPA reports an inspection failure rate of 50% between 2018 – 2021, with a quarter of these found to have failures that are a risk to human health or the environment, including illegal discharges to surface water.  Almost a quarter of the failed systems detected since 2013 and issued with an ‘advisory notice’ had yet to be fixed as of June 2021 [1] 

What needs to change?

Only 1,000 systems out of half a million are inspected annually and this is not enough. There needs to be increased inspection rates, with a particular focus on water bodies deemed to be at risk from pollution from DWWTS so that all problematic systems can be detected and fixed.

Far more effective enforcement is needed so that faulty systems when detected as a pollution source are fixed as a matter of urgency.  

Necessary supports (including grants if needed) for improvements and upgrades should be provided to owners of DWWTS that fail inspection.

Read more:

Sustainable Water Network (SWAN) Response to Public Consultation on the National Inspection Plan for Domestic Waste Water Treatment Systems 2022-2026

SWAN Response to Public Consultation on the Draft River Basin Management Plan – SWAN Submission, August 2017 


[1] EPA (2021) Review of the National Inspection Plan for Domestic Waste Water Treatment Systems 2018-2021. https://www.epa.ie/publications/corporate/consultations/-consultations/OEE—Review-of-2018-2021-NIP-for-public-consultation.pdf