Ireland’s water quality failed to improve in 2025. The latest EPA water quality report shows nutrient pollution still affects a large share of our rivers, lakes, estuaries, and groundwater. Phosphorus and nitrate levels remain too high in many areas, and the agency says action must speed up.
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What the EPA Water Quality Report Found
The Environmental Protection Agency reported little overall improvement in water quality in 2025 and called for faster action. The report tracks the biological health and nutrient levels of Ireland’s rivers, lakes, estuaries, coastal waters, and groundwater each year.
Just over half of monitored waters, 54%, were in high or good biological condition. That figure has barely moved in recent years. Of 717 river water bodies assessed in 2025, 515 stayed stable, 90 improved, and 109 declined, a net loss of 19 waterways.
Roni Hawe, Director of the EPA’s Office of Evidence and Assessment, said the trend should concern everyone. She said Ireland’s water quality is not improving overall, and that the decline in high-status water bodies is a serious warning sign, since these are the best waters and are difficult to recover once lost.
Nutrient Pollution Remains the Main Problem
Nitrogen and phosphorus are the two pollutants driving the poor results. Excess nutrients from farming, poorly treated wastewater, and chemical runoff from fertiliser and pesticides remain the biggest culprits. When too much of either nutrient enters a waterway, algae overgrow, oxygen levels drop, and aquatic habitats suffer.
The numbers show where the pressure is greatest:
- 43% of rivers have nitrate concentrations that are too high, with the problem most pronounced in the east and southeast
- Over 30% of lakes have phosphorus concentrations that are too high, an issue most apparent in the border region
- A fifth of groundwaters and estuaries have nitrogen levels that are too high, again concentrated in the east and south
Agriculture is the main source of nitrogen entering Irish waterways, while both agriculture and wastewater discharge drive phosphorus pollution.
Ireland’s Best Waters Are Losing Ground
The most worrying figures relate to Ireland’s highest-quality rivers. Of the 86 high-status river water bodies monitored in 2025, invertebrate quality held steady in 77, declined in eight, and improved in just one. This is a net loss of five high-quality waterways. That decline reflects a 25% drop relative to the 2010–2012 period.
Lakes show a similar pattern. 54% are in high or good biological quality, leaving 46% in moderate condition or worse. 11 lakes, 5% of those monitored, sit in the worst class, bad biological quality. Most of the lakes failing to reach good quality sit in the Erne and Shannon catchments, where lake phosphorus levels run high.
Where Targeted Action Is Working
The EPA water quality report isn’t all bad news. Six of the 16 rivers surveyed in the Ballyteigue-Bannow catchment in Co. Wexford improved in biological quality in 2025. The EPA called this a welcome sign, though it said further research is needed to establish exactly how the improvements were achieved.
The wider 2019-2024 assessment found that phosphorus levels improved in surface waters specifically where measures were targeted to the right places. Wexford suggests the same principle holds at the catchment level: focused, well-placed action gets results where blanket measures don’t.
Hawe said the EPA’s actions must match the scale of the problem, with measures tailored to the specific challenges facing each water body.
Why This Matters Beyond the Headlines
A 54% pass rate means nearly half of Ireland’s monitored waters fall short of good biological quality. For farms, food producers, local authorities, and anyone drawing water from a river, lake, or well, that’s not an abstract statistic. It’s a signal that nutrient pollution, wastewater overflows, and runoff are active risks in large parts of the country.
Routine testing is how organisations catch these risks early, whether that means checking nutrient levels in a discharge, monitoring a private water supply, or assessing the impact of a site on a nearby waterway. Waiting for the next EPA water quality report to find out is waiting too long.
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Whether you manage a farm, a wastewater system, or a site near a river or lake, regular testing helps you spot problems before they show up in a national report.
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