Nitrogen Reduction Assessment

Nutrient Pressures on Water Quality

The primary water quality issue of concern in Ireland is elevated concentrations of nutrients, i.e. nitrogen and phosphorus. Excess nutrients in waters leads to eutrophication when an overgrowth of algae causes unsatisfactory oxygen conditions, that in turn impacts on the health of our aquatic ecosystems. Nitrogen losses to transitional waters are of particular concern as these waters are sensitive to excess nitrogen and they are in the poorest ecological condition of all waterbody types.

Assessing Nitrogen Load Reductions

The EPA has assessed the nitrogen load reductions needed in major catchments to protect estuarine and coastal ecosystems and achieve Good Ecological Status. An initial assessment published in 2021, using data up to 2019, identified several Catchments of Concern in the south‑east where nitrogen loads discharging to sea were too high. An updated assessment incorporates more recent monitoring data up to 2024 and some improvements to the assessment methodology.

Progress and Remaining Challenges

This updated assessment report shows that some areas have achieved the required nitrogen reductions, and most catchments are now closer to their target than they were for the previous assessment which covered the period 2017-2019. However, the current results still fall short of the levels observed between 2008 and 2011, which remains the period when nitrogen levels were closest to meeting ecological targets over the past 35 years.

Nitrogen Reduction Assessment Reports

2025: Evidence-based targeting of agricultural measures to reduce nitrogen in catchments to achieve water quality objectives

2021: Assessment of the catchments that need reductions in nitrogen concentrations to achieve water quality objectives