Chapter 3 shows data on the quality of water and wastewater in Ireland. We cover five key areas: bathing water quality, drinking water quality, urban wastewater treatment, river water quality and nitrates in groundwater. These indicators provide useful data on national trends over times and are useful from an environmental policy formation and evaluation perspective. Some indicators (such as public water supplies, wastewater treatment and nitrates in ground water) show significant improvement over time, while others (such as bathing water quality and river water quality) have either not improved or gotten worse over time.
The data in this indicator refer to both freshwater and seawater bathing sites.
The proportion of bathing water sites classified as having good water quality improved over the 1990-2024 period. In 2024, 93.4% of these sites had good water quality. This was a slight increase from the 2023 figures of 93.2% and also from the average figure of 87.3% between 2000 and 2004.
In 2024, 96.0% of bathing sites in Ireland were classified as having sufficient water quality. This was down from 96.6% in 2023 and also lower than the average 97.7% in the period 2000-2004.
| Year | Sufficient water quality | Good water quality |
|---|---|---|
| 2000 | 98.5 | 91.5 |
| 2001 | 97.7 | 87.8 |
| 2002 | 97.7 | 84.7 |
| 2003 | 96.9 | 84.7 |
| 2004 | 97.7 | 87.8 |
| 2005 | 96.2 | 90.8 |
| 2006 | 96.9 | 90.1 |
| 2007 | 96.9 | 80.2 |
| 2008 | 93.1 | 77.9 |
| 2009 | 93.1 | 82.4 |
| 2010 | 96.9 | 90.1 |
| 2011 | 98.5 | 83 |
| 2012 | 97 | 66.9 |
| 2013 | 96.8 | 84.4 |
| 2014 | 94.1 | 86.7 |
| 2015 | 93.4 | 83.2 |
| 2016 | 92.9 | 85.8 |
| 2017 | 93 | 84.5 |
| 2018 | 94.5 | 86.2 |
| 2019 | 95.2 | 89.1 |
| 2020 | 95.9 | 89.2 |
| 2021 | 97.3 | 90.5 |
| 2022 | 97.3 | 92.6 |
| 2023 | 96.6 | 93.2 |
| 2024 | 96 | 93.4 |
Three types of public water supplies are monitored for pollutants, including E.coli and Trihalomethane (THM) contamination: public water supplies, public group water supplies and private group water supplies.
Compliance with E.coli standards has been over 98% for public water supplies over the entire 2004-2024 period and for public group water supplies (except for 2004). Compliance of private group water supplies has improved significantly from an average of 82.5% over the 2004-2008 period to 97.7% in 2024.
The compliance rate of public water supplies for THM’s has been worse than for E.coli but improved in 2024. Public group water supplies have shown the biggest improvement with compliance for THM’s increasing from an average of 74.8% in 2009-2013 to 98.8% in 2024. Compliance of public water supplies with THM standards increased from an average of 89.4% in 2009-2013 to 98.4% in 2024, while private group water supplies also increased from 91.3% to 94.9% over this time frame.
| Year | Compliance of public water supplies with THM standard | Compliance of public group water supplies with THM standard | Compliance of private group water supplies with THM standard |
|---|---|---|---|
| 2009 | 87.4 | 70.4 | 89.4 |
| 2010 | 89.3 | 76.2 | 85.5 |
| 2011 | 91 | 87.1 | 93.6 |
| 2012 | 87 | 60.3 | 93.8 |
| 2013 | 92.1 | 79.8 | 94.4 |
| 2014 | 93 | 93.1 | 93.3 |
| 2015 | 91.5 | 87.2 | 95.7 |
| 2016 | 93.1 | 95.7 | 90.9 |
| 2017 | 94.3 | 96.6 | 96 |
| 2018 | 95.1 | 87.9 | 95.1 |
| 2019 | 96.1 | 89.2 | 97.5 |
| 2020 | 97.3 | 89.4 | 93.5 |
| 2021 | 95.3 | 82.61 | 93.75 |
| 2022 | 95.64 | 92.26 | 95 |
| 2023 | 95.52 | 85.45 | 93.69 |
| 2024 | 98.43 | 98.75 | 94.86 |
There has been a significant improvement in the level of treatment of urban wastewater. In 2024 just 0.7% of urban wastewater received no treatment compared with an average of 41% in 1997-1999. The proportion of urban wastewater receiving secondary treatment increased from 21.5% to 59.7% over this period. In 2024, 38.7% of wastewater received secondary treatment with nutrient reduction, up from 4.5% in 1997-1999.
| Year | No treatment | Primary treatment | Secondary treatment | Secondary treatment with nutrient reduction |
|---|---|---|---|---|
| 1997-1999 average | 41 | 33 | 21.5 | 4.5 |
| 2000-2004 average | 30.5 | 21.5 | 39.5 | 8.5 |
| 2005-2009 average | 10.3 | 1.3 | 74.3 | 14 |
| 2010-2014 average | 5.1 | 1.5 | 70.4 | 23 |
| 2015-2019 average | 2.4 | 1.1 | 67.7 | 28.7 |
| 0 | 0 | 0 | 0 | |
| 2020 | 1.4 | 1 | 63.8 | 33.8 |
| 2021 | 1.1 | 1 | 59 | 39 |
| 2022 | 1.1 | 0.9 | 58.4 | 39.5 |
| 2023 | 0.9 | 1 | 58.6 | 39.6 |
| 2024 | 0.7 | 1 | 59.7 | 38.7 |
There was a mixed picture concerning river water quality in Ireland in recent decades. The proportion of rivers and streams with high quality or with poor quality water decreased. Those with good or moderate water quality increased.
The percentage of rivers and streams with bad or poor water quality decreased over time. In the 2022-2024 period, 18% of rivers and streams were of bad or poor quality, compared with 25% between 1987-1990.
The percentage of rivers and streams with good or moderate water quality increased from 49% to 67% over this time frame.
However, the proportion of rivers and streams with high water quality declined severely from 27% in the 1987-1990 period to 15% between 2022-2024.
The proportion of groundwater samples in Ireland with low nitrates - that is less than five milligrams per litre (<5mg/l) - improved from an average of 15.8% in the 1995-1997 to 22.5% in 2024.
The percentage of samples with high nitrate levels (≥50 mg/l) also improved, falling from an average 2.6% in 1995-1997 to 0.6% in 2024.
The picture for groundwater with moderate levels of nitrates (between 5 and <50 mg/l) was more mixed. For example, categories with nitrates between 10 and <25 mg/l fell over this timeframe, while the category between 25 and <37.5 mg/l increased.
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