Catchment News

Significant Pressures: Urban Waste Water

Urban Waste Water Treatment Plants and agglomeration networks (UWW) have been identified as a significant pressure in 20 % (291) of all water bodies that have been determined as being At Risk of not achieving their WFD objectives.

Of these 291 water bodies, 250 are rivers, 15 are lakes, 23 are transitional waters and three are coastal waters (Table 1).

Six of these water bodies have High Environmental Status (HES) objectives. One of these water bodies, Island_030 in Galway is impacted only by UWW while the remaining HES water bodies are impacted by multiple pressures (Figure 1).

Water quality problems in water bodies impacted by Urban Waste Water

Direct discharge of nutrients from urban waste water treatment plants and discharge from combined storm overflows (CSOs) or storm water overflows (SWOs) are the most common water quality problems associated with urban waste water. Emissions of elevated concentrations of phosphorus and ammonia from UWW impact rivers and lakes while emissions of nitrogen and phosphorus impacts transitional and coastal waters while elevated concentrations of microbes impact bathing and shellfish waters.

Table 1. Number of At Risk water bodies with Urban Waste Water (UWW) as a significant pressure

Waterbody (WB)Number of WBsNumber of At Risk WBsNumber of WBs with UWW as a significant pressure% of WBs with UWW as a significant pressure% of At Risk WBs with UWW as a significant pressure
Figure 2. Surface water bodies where urban waste water is a significant pressure either alone or in combination with other pressures.

Possible Solutions and the Next Steps

The River Basin Management Plan (RBMP) outlines the actions that will address the release of nutrients from urban waste water in the 2nd RBMP Cycle. These actions include a €1.7 billion investment by Irish Water in waste water projects, programmes and asset maintenance including €12 million for expenditure on smaller plants which have been identified as significant pressures. In addition, drainage areas plans will be completed for 44 urban areas by 2021. Although this will not directly translate to water quality improvements by 2021, it will help prioritise areas where leaking sewers and misconnections are an issue and where effort should be targeted next.

Find out more:

You can view the individual water bodies where urban waste water is a significant pressure on

You can view a map of sewage treatment locations in Ireland on

For planning and policy, including measures, see

Who is involved?

Quite simply, everyone in Ireland has a role to play. This can be from something as simple as making sure you don’t pollute your local stream, or a local community working together to establish a Rivers Trust to enhance the rivers and lakes in their area, to a Government Department or Agency helping a Minister implement a new policy to help protect and enhance all our water bodies.

This website has been developed and is maintained by the Environmental Protection Agency, and is a collaboration between the Department of Housing, Planning and Local Government, the Environmental Protection Agency, and the Local Authority Waters Programme.


Local Authority Waters Programme

The Local Authority Waters Programme coordinates the efforts of local authorities and other public bodies in the implementation of the River Basin Management Plan, and supports local community and stakeholder involvement in managing our natural waters, for everyone’s benefit.


Environmental Protection Agency

The EPA is responsible for coordinating the monitoring, assessment and reporting on the status of our 4,842 water bodies, looking at trends and changes, determining which waterbodies are at risk and what could be causing this, and drafting environmental objectives for each.


Department of Housing, Local Government and Heritage

The Department is responsible for making sure that the right policies, regulations and resources are in place to implement the Water Framework Directive, and developing a River Basin Management Plan and Programme of Measures to protect and restore our waters.