AIE: Site locations of domestic waste water inspections

Under the AIE Regs to request the following dataset of geographic locations of national septic tank inspections

As per EPA website

The following link (as above) is a dataset that “represents the site locations of Domestic Waste Water Treatment Systems where inspections have been carried out under the National Inspection Plan.

These locations have been captured by Local Authority Inspectors as part of the process of logging inspection details within the Domestic Waste Water Application

The dataset is used by EPA to create various pdf reports but the actual GIS data does not appear to be in the public domain

Statement on the dataset suggests that the locations in this dataset are captured using an integrated map part within the Domestic Waste Water Application whereby the Inspector selects the location on the map. Alternatively, the Inspector can enter the coordinates manually at which point the application then displays the location on the map for verification.

Please provide the data in the GIS format as collected

Note this is not a request for the inspection plans themselves, the annual reports or a breakout by Local Authority areas. It is a request for the mapping data of the inspections

If the dataset includes additional non-confidential fields along with the inspection locations (like the date of the inspection) please include in the file

AIE Request, (24/3/22)

Domestic Waste Water Application: Module in EPAs EDEN System

This Module is the system used by local authority inspectors to log inspected domestic waste water inspections (septic tanks)

This dataset represents the site locations of Domestic Waste Water Treatment Systems where inspections have been carried out under the National Inspection Plan.

These locations have been captured by Local Authority Inspectors as part of the process of logging inspection details within the Domestic Waste Water Application

The locations in this dataset are captured using an integrated map part within the Domestic Waste Water Application whereby the Inspector selects the location on the map. Alternatively, the Inspector can enter the coordinates manually at which point the application then displays the location on the map for verification.

There are a number of datasets available as decision support tools to assist with the implementation of the National Inspection Plan 2018 – 2021 here:

Shallee Priority Area for Action Desktop Report


July 2020

Within the public drinking water source protection area for Drumcliff springs which
supplies Ennis

Hydromorphology (land reclamation)

Small point sources (DWWTS and farmyards)

One operational limestone quarry within the Shallee_010 sub-basin but it discharges
under S4 licence to the Fergus_040 waterbody to the north

EPA licensed facility located beside the quarry (Licence no. P0771) which discharges to ground within the sub basin. There is no process water discharged, only surface water which is discharged to ground from settlement ponds. The discharge is licensed for suspended solids and pH.

Clogrennane Lime Limited (Clare) (CRH)

A quicklime production facility comprising of; Maerz PFR kiln and auxiliary plant, and storage silos

Non operational limestone quarry at Fountain (closed 2010)

Carrigaholt Priority Area for Action Desktop Report


March 2020

Carrigaholt Bay is a designated Shellfish Water

Nutrients (ammonia and orthophosphate) are the significant issues impacting on water quality. Sediment is potentially a significant issue. Chloride and conductivity levels are also significantly elevated. Elevated chloride in freshwater can be an indicator of domestic sewage (or slurry) pollution

Agriculture and domestic wastewater treatments systems are the significant pressures

Village is unsewered, the river periodically floods and septic tanks overflow, putting the shellfish waters at risk

Carrigaholt requires a waste water treatment plant

Section 4s (effluent discharge licence) on Moyana upstream of the village (holiday mobile home park with over 100 mobile homes and seven holiday homes)

The second S4 licence is not operational (it was an oyster nursery)

Tyshe Priority Area for Action Desktop Report


June 2020

Pressures indicated for Tyshe are agriculture and domestic wastewater

The elevated ammonia concentrations could also indicate the presence of farmyard point sources.

Six domestic wastewater systems with high – very high P impact potential along the north and south tributaries of the Tyshe

Agriculture and urban wastewater are listed as the significant pressures

New WWTP for Ardfert was installed in 2017

Dewatering at the Section 4 quarry

The quarry has a section 4 license and is being dewatered – approximately 2500 m3/d on average

Drinking water abstraction at Ardfert South comes under strain in dry summer

Nitrate concentrations are consistently high

Chloride concentrations are consistently high

Elevated nutrients, including orthophosphate, ammonium and nitrate, as well as sediment, are the
significant issues

The Tyshe River, falls within the Banna Drainage District. Kerry County Council has a statutory duty to maintain this Drainage District. The River Tyshe flows to the sea at Blackrock. The outfall at Blackrock is vulnerable to blockage from build-up of sand (Flood Risk Management Plan for the Tralee Bay-Feale River Basin, 2018). Sand and seaweed are excavated out of the channel opening. These works currently take place at least every two weeks, but this can be daily in the winter months. The annual cost of these works is estimated at approximately €150,000. The drainage systems back up when this outfall at Blackrock is not clear. Maintenance work is also carried out to keep tidal flaps, approx. 600m upstream of the outfall, functioning. Sluice gates are manually operated to close on high tides to prevent tide backing up on Tyshe River, once every few weeks (Flood Risk Management Plan for the Tralee Bay-Feale River Basin, 2018). As part of a national Preliminary Flood Risk Assessment, discontinuing the existing regime of removing silt and debris from the outfall at Blackrock is being explored

Adrigole Priority Area for Action Desktop Report

June 2020


EPA initial characterisation predicts the significant pressure to be clear felling of forestry. Domestic
waste water treatment systems as well as agriculture may also present possible pressures.

The 2016 sanitary survey carried out by the Sea Fisheries Protection Authority suggested that potential sources of contamination include slurry spreading and domestic waste water treatment systems.

Important shellfish area

No monitoring data are available on Adrigole Harbour, it is a protected area for shellfish and so would be
sensitive to bacterial contamination. It is notable that there is another river inputting into the harbour (Cappanaparka_East_010). This is not included in the PAA but may also be a potential source of contamination, it is currently unassigned.

Sediment is affecting water quality on the Adrigole river. It is likely that sediment making its way to the
streams from multiple sources including forestry, agriculture and possibly peat harvesting. Nutrient enrichment may also be causing issues

POMs (Programmne of Measures) agreed on septic tanks

Ireland has EU obligations in relation to water pollution from septic tanks

Is there any research on the national and catchment level impact of septic tanks ?

There was a POMs (Programmne of Measures) agreed after a court case that set out what Ireland is required to do to rectify the septic tank failings identified in the proceedings ?

Extract from presentation entitled

Domestic Waste Water Treatment Systems: Expansion of Grant Scheme
Colin Byrne, Department of Housing, Planning and Local Government

Full presentation is here:

Domestic Waste Water Treatment Systems

The number of registered domestic waste water treatment systems increased by 0.9% in 2020 to 475,990. There was an increase in every local authority in 2020 with Donegal recording the highest annual increase of 1.2% (see Figure 1 and Table 1).

In 2020 Cork had the highest proportion of domestic waste water treatment systems at 11.4% followed by Galway (8.8%), Kerry (7.1%), Donegal (6.4%), Mayo (6.1%), Tipperary (5.5%) and Wexford (5.3%). These seven counties accounted for 50.6% of all individual waste water treatment systems (see Table A and Figure 2).

Cork accounted for 14.3% of all new registrations in 2020 followed by Donegal at 8.9% (see Table 2).

Household owners accounted for 97.1% of all registered waste water treatment systems in 2020. Public authorities accounted for 1.5% and Other non-domestic owners accounted for the remaining 1.4% (see Table 3). In Longford public authorities accounted for 4.3% of all owners in 2020 whereas in Kildare they only accounted for 0.1%.

National Inspection Plan 2018-2021: Domestic Waste Water Treatment Systems

This report outlines the proposed third national inspection plan for domestic waste water treatment systems (DWWTS) for the period 2018 to 2021.

The Water Services Act 2007, as amended by the Water Services (Amendment) Act 2012 requires the EPA to prepare a national inspection plan for DWWTS. The purpose of the plan is to protect human health and water quality from the risks posed by DWWTS (also known as septic tank systems).

The EPA prepared the first national inspection plan for DWWTS in 2013 covering the period 2013 to 2014. The plan required local authorities to undertake a minimum of 1,000 inspections each year across the country. The EPA developed a risk based methodology to assist the local authorities with the selection of locations for inspections. The methodology took into account the potential risks that DWWTS pose to both human health and water quality.

The second national inspection plan for DWWTS in 2015 outlined the inspection process covering the period 2015 to 2017. Some minor changes were made to the risk maps used for site selection as additional environmental data had become available. This also resulted in a slight change to the number of inspections in some counties.

This third plan has been prepared for the years 2018 to 2021. The risk-based methodology has been updated to take into account additional information gathered on water quality during the preparation of the River Basin Management Plan 2018 – 2021. Further information on the revised methodology is provided in section 2 of this report.

The minimum number of inspections across the country remains at a 1,000 inspections per annum. However, the minimum number of inspections required in each local authority area has changed in response to the revised methodology and further details are provided in section 3 of this report. The final number of inspections remains a matter for each local authority. Additional inspections should be carried out where evidence exists that DWWTS are causing an issue in a particular catchment.

Under the national inspection plan local authority inspectors are required to undertake a minimum number of inspections each year. Any shortfall in the number of inspections completed at the end of the 2015 to 2017 reporting period will be carried over and added to the number of inspections to be undertaken in 2018.

Close to half of all inspection failures have been related to the operation, maintenance and desludging of DWWTS.

Private wells may be at risk of contamination if the DWWTS are not sited, installed or operated correctly (in 2016, it was found that 51% of DWWTS, with private wells on site, failed inspection).


Local authorities must maintain a register of all complaints and other inspections, such as water pollution incident investigations, that relate to DWWTS. But this file is not in the public domain

Likelihood of Inadequate Percolation

Potential risk to groundwater supplies from DWWTS

National inspection plan 10 risk zones map

Minimum number of inspections by county

Percolation tests for site assessment for domestic wastewater treatment systems

Project AttributeProject Details
Project TitlePercolation tests for site assessment for domestic wastewater treatment systems
EPA Project Code2019-W-DS-35
Lead OrganisationUniversity of Dublin, Trinity College (TCD)
CoordinatorLaurence Gill
EPA Research 2014 – 2020 Theme(s)Water: Theme 4: Understanding, Managing and Conserving our Water Resources
EPA Research Pillars
Project Start and End DatesStart: 02/03/2020
End (if applicable): 01/03/2021
Revised End Date (if applicable): 01/06/2021
EPA Project TypeDesk Study
EPA Award TypeSTRIVE – Project Based Awards
Current Project StatusGrant Awarded
Total Funding Amount90131.20
Project Abstract/DescriptionThis research will evaluate different methods of how to assess the percolation characteristics of soils as part of the site assessment process used for the design domestic wastewater treatment systems (DWWS). Currently, site assessment (and subsequent DWWTS design) is prescribed in the EPA Code of Practice (EPA, 2009) which requires an on-site falling head percolation test, known nationally as the T-test, to be carried out. However, this method has limitations for more low permeability subsoils and so an alternative method needs to be evaluated. Several different approaches can be taken to determine a soil’s saturated hydraulic conductivity, either by percolation tests (carried out in the laboratory or in the field) or via soil size distribution analysis. The project will focus on a review of the different methodologies used internationally and also provide a clear explanation of the theoretical background for water percolation. It will then investigate the Irish situation specifically and translate the existing data / findings in to a proposed new approach to site assessment and associated percolation testing, in addition to how it might be incorporated into the Code of Practice, in order to overcome the issues with the existing falling head test for low permeability subsoils. As set out in the Communication Plan (see Section C of the proposal) the project will produce the following: a Final report for the EPA, a minimum of 1 peer-reviewed publication in a high quality international journal, and a database of over 800 falling head test and around 20 constant head percolation tests carried out across the country which will be compiled for EPA and stored on its Research Data Archive (SAFER). In addition, the project will set up a Stakeholder advisory group of members hopefully representing the following organisations: EPA, Local Authority Waters Programme (LAWPRO), Local Authorities, An Bord Pleanala, Geological Survey Ireland, Site Assessors, National Standards Association of Ireland (NSAI), Irish Onsite Wastewater Association (IOWA), Irish Water Treatment Association (IWTA), National Federation of Group Water Schemes (NFGWS) and Irish Water.
EPA Scientific OfficerKarenRoche