Search for a licence or permit

River nitrogen levels increased in 2025

Date released: March 19, 2026

  • Nitrogen levels in rivers increased by 10% in 2025, based on data from 20 representative monitoring sites. Nitrogen levels in the south‑eastern half of the country are too high to support good ecological health in our water bodies. 
  • The primary source of nitrogen in Irish rivers is agriculture, from excess losses of nitrogen in chemical and organic fertilisers. 
  • Nitrogen levels in rivers change due to a combination of factors, including nitrogen inputs, agricultural land management practices and weather patterns. 
  • Targeted agricultural measures are required to reduce nitrogen losses and achieve improvements in water quality.

19 March 2026: The Environmental Protection Agency (EPA) has today published its Early Insights Nitrogen Indicators, which provide the latest assessment of nitrogen levels in Ireland’s major rivers for the period January to December 2025. The report shows that average annual nitrogen levels at 20 representative monitoring sites increased by 10% in 2025 compared with 2024. This is consistent with earlier findings of elevated nitrogen levels during the January–June 2025 period.

Nitrogen levels remain elevated across the south‑eastern half of the country, where agriculture is the primary nitrogen source. Sustained and targeted action to reduce nitrogen losses is required in the higher‑risk agricultural areas, where the farming intensity is relatively high and the soils are freely draining. The EPA’s Farm and Landscape Measures for Agriculture (FLAG) map identifies these high‑risk areas and can be used to help target action. Targeted actions are needed to support improvements in aquatic ecological health and improve overall water quality.

Commenting on the report, Pat Byrne, Director of the EPA's Office of Radiation Protection and Environmental Monitoring, said:

“The Early Insights Nitrogen Indicator provides timely evidence on how nitrogen levels in our rivers are changing. The increase observed in 2025 highlights the continued pressure on water quality and underlines the need for sustained, targeted action to reduce losses of nitrogen used in agriculture, particularly in higher‑risk catchments in the southeastern half of the country. "

The Early Insights Nitrogen Indicator Report: Nitrogen concentrations in selected major rivers, January–December 2025 is available on the EPA website. Further information on local water quality, including the FLAG map to help target agricultural measures is available here. 

Further information: Emily Williamson, 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 was published in October 2025 on the EPA website.

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 2024 was published in July 2025. 

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 here 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.

Phosphorus: Phosphorus is a nutrient which is essential for plant growth. As with nitrogen, too much phosphorus in a water body can lead to the over-growth of plants and algae which disturb the ecosystem. Excess phosphorus is a particular concern for the ecological health of rivers and lakes. The main sources of excess phosphorus in the environment are agriculture and wastewater.

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 here. 

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, Local Authorities Water Programme (LAWPRO) and Department of Housing, Local Government and Heritage website that is used to share data, information, and resources on water in Ireland.