Catchment News

EPA publishes water quality Q-value results for rivers surveyed in 2022

26 January 2023: EPA Water Quality Q-value results for rivers surveyed in 2022 are now available. These reflect average water quality at monitored locations.

View Q values on EPA Water Map: – see Monitoring and Flow/Q values

River Quality Surveys:

Data download: – see Water Quality and Monitoring/ Biological Q results 19/01/2023

About Q values and biological monitoring of our rivers

Information on the relative abundance and condition of different algal, plant and animal communities is used to assess the ecological health of Ireland’s waters. Every year, over a thousand river sites and dozens of lakes, estuaries and coastal waters are surveyed by biologists.

The EPA Q-Value System is based on the well-established sensitivities, abundance and diversity of macroinvertebrates and their relation to water quality. The Q Value system has been used to assess the quality of Irish rivers since the 1970’s. It has a nine point scale ranging from Q5 indicating high quality to Q1 bad quality.

At each river site the macroinvertebrates such as juvenile (larvae) and adult insects, crustaceans, mites, snails, mussels, leeches, and worms are examined. The relative abundance of pollution sensitive species versus pollution-tolerant species give an indication of the ecological health of the river (Q-value).

Some of the pollution-sensitive species used to assess the health of our waters.

The scheme mainly reflects the effects of organic pollution i.e. deoxygenation and eutrophication i.e. nutrient enrichment, but can also reflect the effects of toxic chemical pollution e.g. pesticides, and general habitat degradation.

Biological macroinvertebrate surveys are usually undertaken in the most sensitive time of the year, summer to early autumn period, when flows are likely to be relatively low, water temperatures are higher and any stresses on aquatic ecosystems are expected to be at a maximum. Biological material for examination is obtained by kick-sampling, a method used to disturb the river bed substrate and dislodge the resident macroinvertebrates living in the shallower, faster-flowing areas (riffles) into a standard pond net. The sample is then transferred to a white tray and the assessment of water quality is completed on the river bank.

How to kick sample – video with Teagasc and LAWPRO

This video by Teagasc gives a good overview of how biological samples are taken and reflect the health of a river.

2022 River Q Values

2022 River Q Value Survey Results

How to view the 2022 River Q Value results on the EPA Water Map

All active layers on the EPA Water Map can be filtered.

To view 2022 Q Value results, first switch on ‘Latest Q values’ in the Monitoring menu, then select Active Layers (1) on the left hand side menu. When this menu opens, click the Cog symbol (2) beside Latest River Q Values. Click Filter (3) and use the below filter settings and finally click Add Filter to only show 2022 results:

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.