Early insights into the Environmental Protection Agency’s (EPA) annual assessment of Irish rivers predict disappointing results for 2025.
After encouraging signs in 2024, the latest figures suggest a reversal in 2025. Nitrogen concentrations increased by 16% in the first half of 2025 compared with the same six-month period in 2024.
While short-term fluctuations are not uncommon, the scale of the increase has raised concern over Irish river quality.
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A Step Backwards for Irish Rivers
In 2024, nitrogen concentrations were at their lowest level since 2016. The EPA tracks Irish river quality from 20 representative monitoring sites. These sites are found at the most downstream points on major rivers around Ireland.
The 2024 results indicated that regulations and improvements in farm practices were beginning to show results. However, the early 2025 data complicates that narrative.
A 16% increase in nitrogen concentrations suggests that current measures may not be delivering the expected results.
The EPA notes that nitrogen levels fluctuate from year to year. This is due to changing source loading, agricultural land management, and weather patterns. Heavier rainfall, for example, can increase runoff, carrying nitrogen from land into rivers.
The EPA has confirmed it’s investigating the causes of the 2025 increase. They hope to determine whether the change reflects short-term conditions or longer-term pressures.
Nitrogen Concentrations Increase: Regional Differences
The EPA, found regional differences where nitrogen concentrations increased:
- Catchments mainly located in the east, south, and southeast show higher average nitrogen concentrations
- Catchments in the west and northwest generally record lower concentrations.
These differences reflect variations in:
- Farm intensity and livestock density
- Soil drainage characteristics
- Rainfall and climate conditions
The EPA warns that nitrogen levels “remain too high” in the south-east. The south, east, and southeast have many dairy farms. These activities contribute to higher nitrogen levels and increase pressure on water quality.
Agriculture’s Central Role in Nitrogen Concentrations Increase
In Ireland, the EPA identifies agriculture as the main source of nitrogen, responsible for about 85% of nitrogen loadings in rural catchments.
Under the EU Nitrates Directive, farmers must ensure that nitrogen from organic manure does not exceed 170 kilograms per hectare per year.
The EPA recognises that efforts are underway to reduce nitrogen levels, but says the scale and pace of action must increase.
Why Rising Nitrogen Matters
Elevated nitrogen concentrations can have serious ecological consequences:
Over time, these effects can affect biodiversity, water clarity, and ecosystem resilience.
A recent EPA assessment found that 48% of Irish water bodies now fail to meet Environmental Quality Standards (EQS). This means nearly half of Ireland’s aquatic ecosystems are not achieving the health and stability expected under EU environmental objectives.
While nitrogen is not the sole cause, it remains a major contributor affecting river quality.
The Need for Continuous Monitoring
As nitrogen concentrations increase, especially in vulnerable catchments, it highlights that current strategies are ineffective. Without progressive action, excessive nutrients will continue to threaten our ecosystems and water quality.
Regular water monitoring is a key part of the solution. Identifying high nitrogen levels early allows for fast and targeted intervention.
At Southern Scientific, we support communities, farmers, and local authorities with reliable environmental and drinking water testing. Our ISO 17025-accredited laboratory analyses over 10,000 water samples each year for more than 1,000 organisations, including local authorities, Uisce Éireann, and group water schemes.
Our water testing services can detect nutrient contamination, including nitrates, helping clients understand risks, protect water quality, and track whether mitigation measures are working.
To assess nitrogen levels in your water or river catchment, contact our team of experts today.
