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River nitrogen levels show an increase in the first half of 2026 compared to the same period in 2025

Date released: September 16, 2026

  • The EPA’s Early Insights Nitrogen Indicator Report shows that river nitrogen levels were over 4% higher in the first half of 2026 than in the same period of 2025.
  • Nitrogen levels remain too high across much of the south and southeast, putting pressure on our rivers and estuaries.
  • Agriculture is the main source of nitrogen entering Irish rivers, mainly from fertiliser and manure.
  • More targeted actions on farms are needed to reduce nitrogen losses and improve water quality.

The Environmental Protection Agency (EPA) has today published its Early Insights Nitrogen Indicator Report, which provides an early indication of trends in river nitrogen levels based on the first six months of the year.

Average nitrogen concentrations at representative monitoring locations in 20 major rivers increased by 4.3% in the first half of 2026 compared with the same period in 2025. This follows an increase in river nitrogen levels between 2024 and 2025.

When too much nitrogen gets into rivers, lakes, estuaries and coastal waters, it can cause an overgrowth of algae which depletes oxygen and impacts the habitat for other species. The greatest nitrogen pressures remain concentrated in the south-eastern half of the country, driven largely by agricultural activities. Reducing these pressures will require targeted action in the most vulnerable catchments, particularly where farming intensity is high and free draining soils allow nitrogen to move readily to waters. The EPA's Farm and Landscape Measures for Agriculture (FLAG) map identifies where measures to reduce agricultural nitrogen losses are most needed.

Commenting on the report, Roni Hawe, Director of the EPA, Office of Evidence and Assessment, said:

“These results will be disappointing for many, given the greater focus in recent years on reducing nitrogen losses to water and the work being undertaken by farmers, industry and other stakeholders to address the issue. While there has been growing engagement and a stronger emphasis on targeted measures, these findings highlight that more work is needed to translate actions on the ground into improvements in water quality. There is also a need for stronger joining up of policy and practice, recognising that measures to improve water quality can deliver wider benefits for agriculture, biodiversity and climate.”

The Early Insights Nitrogen Indicator Report: Nitrogen concentrations in selected major rivers, January–June 2026 is available on the EPA website. Further information on local water quality, including the FLAG map to help target agricultural measures, is also available online.

ENDS

Further information: EPA Media Relations Office 053-9170770 (24 hours) or media@epa.ie

NOTES TO EDITOR

EPA water quality reporting: The EPA undertakes a full assessment of the overall quality and ecological status of Ireland’s waters every three years. The latest full assessment covering the period 2019-2024 was published in October 2025 on the EPA website.

Between full ecological status assessments, a biological quality indicators report is published to provide an interim assessment of changes in the biological condition of water bodies. Water Quality in 2025 - An Indicators Report was published June 2026 in is available online.

The EPA also publishes water indicator data for over 1000 monitoring points from the national water monitoring network, on an annual basis. The latest report on Nitrogen and phosphorus concentrations in Irish waters 2025 was published in July 2026. 
In 2021 and 2025, the EPA published an assessment on the nitrogen reductions that were needed in major catchments to support healthy aquatic ecosystems. The most recent assessment can be found on the EPA website and included data up to 2024.

Water Body: A water body is an area of water, which is usually either the whole or part of a lake or coastal water, or a section of a river or an estuary (e.g. Lough Ree is one water body whereas the River Lee is divided into nine water bodies for monitoring purposes).

Nitrate: Nitrate is a form of nitrogen which is a nutrient and essential for plant growth. Too much nitrogen in a water body can lead to the over-growth of plants and algae that outcompete and displace other flora and fauna. This excessive growth can also cause oxygen depletion and damage the ecology of our water bodies. Our estuaries and coastal waters are particularly sensitive to high nitrogen concentrations. The main source of excess nitrate in the environment is agriculture, with wastewater also contributing. Nitrate concentrations above the Drinking Water Standard can pose a risk to human health, particularly for young children.

Pressures impacting on waters: The EPA has published a series of reports on the main pressures impacting on waters which are available at Update on pressures impacting on water quality. Catchment level information on water quality is available on the website.

River Basin Management Plan: The River Basin Management Plan sets out the national policy and actions that are being taken by all sectors to improve and protect water quality. Further information about the National River Basin Management Plan is available on the Department of Housing, Local Government and Heritage website.

www.catchments.ie: A collaborative EPA, River Basin Management Service and Department of Housing, Local Government and Heritage website that is used to share data, information, and resources on water in Ireland.