Just over half (53%) of the 2,355 river water bodies assessed nationally are in satisfactory ecological health being in either good or high status. The remaining 47% are in moderate, poor or bad ecological status. The decline in surface water quality is mostly driven by the decline in river water quality which has declined by 5.5%. This decline is marked by a drop in the number of high status river waters, which have declined by a third since 2009 and an increase in the number of poor status waters. The number of the most seriously polluted (bad status) river water bodies has also increased after many years of improvements. 

There has also been a substantial loss in the number of highest quality biological sites (i.e. Q 5). These sites are important reservoirs of aquatic biodiversity and provide a home to species most sensitive to pollution. In the most recent monitoring period (2016-2018) only 20 sites were classified as highest quality (0.7% of sites) compared with 575 between 1987 and 1990 and 82 between 2001 and 2003. This is an all-time low. This is an area where substantial effort is required to protect the few remaining highest quality rivers and where feasible return impacted ones back to their previous condition.



Of the 215 lakes and 9 reservoirs assessed under the Water Framework Directive, half (50.5%) are in good or better ecological health. This represents an improvement in lake status since the last assessment but overall the picture for lakes is similar to what it was in the baseline period 2007-2009. Although, trend analysis over the period 2013-2018 has indicated an increase in the concentration of total phosphorus, a key nutrient in lake ecology, in over a quarter of lakes analysed. Higher nutrient concentrations can increase the likelihood of algal blooms which can damage lake ecology.



In Ireland, 92% of groundwater bodies met their good chemical and good quantitative status objectives, accounting for 98% of the country by area. 38 groundwater bodies (7.4%) were at poor chemical status and two groundwater bodies (0.4%) failed to meet the quantitative status objective. Over a fifth (22%) of groundwater sites had concentrations of nitrate greater than 25 mg/l NO3, which is considered as a high nitrate concentration. This is an increase of 5.2% of sites since 2018. Generally, groundwater in the south and southeast of the country continues to have the higher nitrate concentrations, and the most substantial nitrate increases.


Transitional (estuarine) and coastal waters

Results from a six-year ecological status assessment from 2013-2018 indicate little change in the quality of our transitional (estuarine) and coastal waters. Transitional waters, the collective term for estuaries and lagoons, have the poorest water quality, with only 38% of water bodies in good or better ecological health. Phosphorus and nitrogen inputs via rivers to estuarine waters have increased by 31% and 16%, respectively, since 2014, indicating an increase in pressures coming from catchment-wide sources.

For coastal waters, the number of water bodies in good or better ecological health is much higher at 80%, making them some of the best quality coastal waters in Europe. This tends to reflect their more open exposed nature and greater capacity to absorb nutrients when compared to more sheltered transitional waters. The latest details on water quality in Ireland, including maps showing water quality to the end of 2018, is available on the “Catchments.ie – Water, from source to sea” website (www.catchments.ie).


Ireland's marine environment

Ireland’s marine environment is one of the largest in the European Union (EU) and is nearly 10 times its land area. The temperate waters that surround Ireland are highly productive and provide a rich mosaic of marine life, including hundreds of species of invertebrates and fish, 24 species of whales and dolphins, breeding colonies of both the common and grey seal and some of the largest breeding populations of seabirds in Western Europe. The assessment of this wider marine areas is covered under the EU Marine Strategy framework Directive.

Ireland’s location in the Atlantic Ocean on the edge of the European continent has meant that its marine environment has remained relatively unpolluted. In recent years, however, the level of environmental stress, from both internal and external sources, has increased. Coastal development, particularly during the 1990s, has resulted in an increase in the range and magnitude of pressures that have the potential to impact negatively on the quality of Ireland’s tidal waters.