Water Quality Ireland – Why 48% of Rivers and Lakes Are Failing and What Is Being Done

Water quality Ireland is a growing concern, with the latest EPA assessment confirming that almost half of the country’s surface waters are not meeting environmental standards. The Water Quality in Ireland 2019-2024 report, published in October 2025, found that just 52% of rivers, lakes, estuaries and coastal waters are in satisfactory ecological condition – down from 54% in the previous 2016-2021 assessment. This guide covers the full picture of water quality across the island, from nutrient pollution and fish kills to drinking water, wastewater infrastructure and the community-led efforts working to reverse decades of decline.

Ireland’s waterways are central to the country’s identity, economy and ecosystems. They support drinking water for over five million people, sustain agriculture and tourism, provide habitat for species like the Atlantic salmon and freshwater pearl mussel, and underpin the broader biodiversity that defines the Irish landscape. Yet the pattern since the first Water Framework Directive assessment in 2007-2009 has been one of gradual deterioration, with localised improvements consistently offset by new declines elsewhere.

📊 The State of Ireland’s Waters

The EPA monitors water quality through a national network of over 1,500 stations covering rivers, lakes, estuaries, coastal waters, canals and groundwaters. The 2019-2024 assessment represents the most comprehensive picture available and feeds directly into Ireland’s obligations under the EU Water Framework Directive.

The headline finding is stark. Of all monitored surface waters, 48% are in unsatisfactory condition – meaning they fail to reach “good” or “high” ecological status. Transitional waters, which include estuaries and coastal lagoons, are in the worst shape of any category, with 70% in unsatisfactory condition, up from 64% in the last assessment period. The one bright spot is groundwater, where 92% of sites are in good status, and canals, where 87% meet their targets.

The decline is not uniform. Some rivers have improved thanks to targeted interventions, while others have deteriorated due to changing land use pressures, population growth and ageing infrastructure. The overall direction, however, is one that Ireland’s own environmental agencies describe as unsatisfactory and incompatible with EU commitments.

🧪 Nutrients – Nitrogen and Phosphorus

The two most significant pollutants affecting Irish water quality are nitrogen and phosphorus. Both are essential nutrients in small quantities, but when they enter waterways in excess – primarily from agricultural run-off, wastewater discharges and septic tank systems – they drive a process called eutrophication. This causes excessive algal growth, depletes oxygen levels and degrades habitat for fish and invertebrates.

The EPA’s 2024 nutrient monitoring report, published in July 2025, draws on data from over 1,500 stations. The findings are mixed. Nitrogen levels in rivers reduced nationally in 2024 compared to 2023, but they remain stubbornly high in the southeast of the country, where intensive dairying dominates. There has also been some reduction in groundwater nitrate concentrations in the southeast, although groundwater levels nationally have shown little overall change. Estuarine and coastal waters are slower to respond to improvements on land, and the number of estuarine and coastal waterbodies with unsatisfactory nitrogen levels actually increased slightly in the latest data.

Phosphorus concentrations have not changed significantly and remain elevated in localised areas associated with poorly draining soils. Around 27% of river monitoring sites show high phosphorus concentrations. The sources are diffuse – run-off from grazed land, slurry spreading on saturated soils, poorly maintained septic tanks and inadequately treated wastewater all contribute.

Agriculture is the single largest pressure on water quality in Ireland. Nutrient losses from farmland account for the majority of nitrogen and phosphorus reaching rivers and lakes, driven by stocking density, fertiliser use, slurry management and the condition of field drainage. The rapid expansion of the dairy sector since the abolition of EU milk quotas in 2015 has intensified these pressures, particularly in the south and southeast.

🐄 The Nitrates Directive and Derogation

Ireland’s agricultural nutrient management is governed by the EU Nitrates Directive, which limits the amount of nitrogen from livestock manure that can be applied per hectare of farmland. The standard limit is 170kg of nitrogen per hectare. Ireland has operated under a derogation that allows more intensive farms to apply up to 220kg/ha (reduced from the original 250kg/ha), subject to conditions including nutrient management plans and mandatory soil testing.

This derogation has come under increasing scrutiny from both the European Commission and environmental groups, who argue that Ireland’s intensive dairy expansion is incompatible with its water quality obligations. The EPA’s data showing persistent nitrogen elevations in the southeast – the heartland of Irish dairy farming – has strengthened calls for the derogation to be further reduced or phased out. For farmers, the derogation is critical to the economic viability of intensive grassland systems, making this one of the most politically charged environmental debates in the country.

🐟 Fish Kills – A Recurring Crisis

Fish kills are among the most visible and distressing symptoms of poor water quality. Inland Fisheries Ireland published a landmark report in 2024 documenting 2,107 fish kill events across Irish rivers and lakes between 1969 and 2022. Agriculture was the most common known cause, followed by eutrophication, industrial discharges, municipal sources, mining and construction. Between January 2023 and July 2024, IFI recorded 30 fish kill events with an estimated 19,000 fish killed.

The issue returned to national attention in August 2025 with the catastrophic fish kill on the River Blackwater near Mallow in County Cork – the largest single fish kill ever recorded in Ireland. An estimated 32,000 salmon and brown trout died across a 37-kilometre stretch of the river after an unknown waterborne irritant entered the water. Despite an extensive inter-agency investigation involving IFI, the EPA, Cork County Council and the Marine Institute – including testing for 900 chemicals, heavy metals and pesticides – no definitive cause was identified. The investigation concluded that a short-lived pollution event had occurred and dissipated before it could be detected, highlighting what agencies described as a “detection gap” in Ireland’s monitoring infrastructure.

A separate EU-commissioned report published in February 2026 recommended that Ireland develop a new multi-agency protocol for responding to major fish kills, improve real-time monitoring on major rivers, and close the detection gap that allowed the Blackwater pollutant to escape identification. An inter-agency protocol group has been established by IFI to develop this new framework.

🚿 Wastewater and Raw Sewage

Ireland’s wastewater infrastructure has been a persistent weak point. The EPA’s Urban Wastewater Treatment in 2024 report, published in October 2025, found that while investment is delivering improvements, serious deficiencies remain. The volume of raw sewage discharged daily has halved since early 2024, but 15 towns and villages were still discharging untreated sewage directly into rivers and coastal waters as of mid-2025. This is down from 19 at the start of 2024, and is expected to decrease to 11 by the end of 2025.

Treatment at 14 of Ireland’s 185 large urban areas failed to meet EU standards in 2024. Approximately half of all wastewater generated in these large areas was produced by the 14 non-compliant sites. The failure of the Ringsend treatment plant in Dublin is of particular concern, as it treats wastewater for a population equivalent of over two million people – more than 40% of the national total. Uisce Eireann has invested over €550 million in upgrading Ringsend, with works expected to bring it into compliance during 2025.

Nearly 60% of all wastewater discharged from treatment plants was not consistently meeting the standards to prevent pollution in 2024. Almost half of these failures were attributed to poor operational management rather than capacity constraints – a finding the EPA described as “not good enough.” The agency has prosecuted Uisce Eireann 28 times for failing to treat wastewater properly and issued 20 legally binding directions in 2024 alone. Uisce Eireann invested over €481 million in wastewater infrastructure during 2024, bringing total investment since 2020 to over €2 billion.

🚰 Drinking Water Quality

Despite the pressures on rivers and lakes, the quality of drinking water from public supplies remains very high. The EPA’s Drinking Water Quality in Public Supplies report for 2024, published in July 2025, confirmed that over 99.8% of samples complied with bacterial and chemical limits. However, many supplies still lack the robust treatment needed to guarantee long-term resilience.

The EPA’s Remedial Action List identifies supplies that are “at risk” and require improvements. In 2024, the number of people served by supplies on this list fell to approximately 497,000, down from 561,000 in 2023. Long-term boil water notices numbered 33 in 2024, down by a third compared to the previous year. The number of supplies affected by Trihalomethanes – a disinfection byproduct – reduced from 25 to 19, serving approximately 245,000 people.

Lead in drinking water remains a significant concern. Ireland has had a National Lead Strategy in place since 2015, but the EPA has described progress as “far too slow.” The legal limit for lead in drinking water will halve in 2036 (from 10 micrograms per litre to 5), placing additional urgency on Uisce Eireann and the Department of Housing to accelerate removal of lead from the supply network and public buildings. The risk is greatest for young children and unborn babies.

🏖️ Bathing Water

Bathing water quality tells a more positive story. The EPA’s 2024 bathing water report found that 81% of Ireland’s designated bathing sites achieved “Excellent” water quality – the highest number of excellent classifications since 2014. Overall, 96% of sites met or exceeded the minimum “Sufficient” standard. Just two beaches were classified as Poor in 2024: Lady’s Bay in Buncrana and Sandymount Strand in Dublin.

Heavy rainfall remains the greatest threat to bathing water quality. Although 2024 was drier overall than 2023, pollution events still occurred during heavy downpours, particularly in August. The EPA recorded 34 pollution incidents at bathing waters in 2024, down from 45 in 2023, and local authorities issued 79 prior warning notices – a dramatic decrease from 275 the previous year. Urban wastewater-related incidents were the most frequently reported cause of beach closures.

🌿 What Is Being Done

Water Action Plan 2024

Ireland’s third-cycle River Basin Management Plan, branded as the Water Action Plan 2024, sets out the national framework for protecting and restoring water quality up to 2027. It identifies priority areas for action and coordinates measures across agriculture, wastewater, urban development and industry. The plan is overseen by the Department of Housing, Local Government and Heritage and implemented at local level through the Local Authority Waters Programme (LAWPRO).

LAWPRO employs Community Water Officers in every county who work directly with local people, community groups, farmers and public bodies to deliver water quality improvements. The programme also administers the Community Water Development Fund, which awarded over €700,000 in grants to 155 community water quality projects in 2024.

Farming for Water EIP

The Farming for Water European Innovation Partnership, launched as a pilot in March 2024, represents the most significant farmer-focused water quality initiative in recent years. Managed by LAWPRO in partnership with Teagasc and Dairy Industry Ireland, the project works directly with farmers in Priority Areas for Action to implement over 40 measures including riparian buffer zones, hedge and tree planting, stream fencing, alternative water supplies and sediment traps.

With a total budget of €50 million for on-farm measures up to 2027, the Farming for Water EIP had attracted over 4,300 farmer applications by late 2025. Participants receive payments for completing farm water quality visits, rainwater management plans, training courses and nutrient management plans, as well as funding for capital works. The project is designed to complement existing schemes under the Common Agricultural Policy and the ACRES agri-environment programme.

National Barrier Mitigation Programme

In partnership with Inland Fisheries Ireland, the government is funding the removal of barriers – such as impassable weirs and dams – that prevent fish from migrating along rivers. Since 2024, 14 barriers have been fully mitigated and 27 further mitigations are currently active. This programme contributes to the EU Nature Restoration Regulation target of restoring 25,000 kilometres of free-flowing rivers across Europe and is a direct benefit for species like Atlantic salmon, sea trout and lamprey.

Urban Nature-Based Solutions

Between 2024 and mid-2025, LAWPRO completed 20 urban nature-based solutions capital projects. These use plants, soils and natural drainage features to manage, store and clean surface water before it enters piped drainage systems. The approach is increasingly important for climate adaptation, as more frequent intense rainfall overwhelms conventional grey infrastructure. The Budget 2026 allocation will fund upscaling of this approach across local authorities nationwide.

⚠️ The 2027 Deadline

Under the Water Framework Directive, Ireland is required to achieve “good” ecological status in all its waters. The target date is 2027. The EPA and multiple government reports have acknowledged that Ireland will not meet this deadline at the current rate of progress. The pattern of overall decline since the first assessment period, combined with the scale of infrastructure investment still required and the continuing intensity of agricultural pressures, means that full compliance remains years away.

Ireland is not alone in this challenge – most EU member states will miss the 2027 deadline – but the continuing deterioration of Irish waters at a time when other countries are stabilising or improving their water quality puts Ireland in a particularly difficult position. The European Commission has taken enforcement action against Ireland on multiple occasions over water-related failures, and further action remains possible.

What the data shows, however, is that targeted interventions work. Where farmers, communities and agencies focus resources on specific catchments and specific pressures, water quality can and does improve. The challenge is scaling those successes from localised pilots to national recovery – and doing so at a pace that matches the urgency of the decline. For a wider view of how peatland degradation, agricultural intensification and habitat loss are affecting Ireland’s natural environment, see the related articles below.