A new report from the EPA shows the majority of rivers in Co Mayo have high, or good quality water.
However, the Environmental Protection Agency has warned that there's an urgent need to curb nitrogen pollution in Ireland's surface and ground waters, which continue to be under pressure from human activities. It says Ireland is in danger of losing its excellent coastal water quality unless urgent action is taken to reduce the amount of nitrogen from farms entering Irish waters.
The report into Ireland's rivers, lakes, estuaries, and groundwaters said that despite some improvements in the biological quality of our rivers, many are not as ecologically healthy as they should be.
Out of 1,836 river bodies examined, 43% were unsatisfactory and 230 had worsened since 2017, while 345 rivers had improved water quality.
The biggest problems are caused by nitrogen and phosphorous being washed into water courses, primarily from farms, but also from wastewater.
This causes overgrowth of plants and algae, displacing other flora and fauna, resulting in oxygen depletion. It damages the ecology of Ireland's water bodies and puts human health at risk.
The report highlights that agriculture is causing particular pressure in parts of the south, southeast and east of the country. The EPA said urgent action is now needed to reduce nitrogen pollution in the Bandon, Lee, Blackwater, Suir, Nore, Barrow and Slaney rivers.
It also called for continued and sustained investment by Irish Water to address water quality issues from urban wastewater.
In Mayo, 55 rivers have high water quality, 77 are described as good, 40 moderate and just 9 rivers in the county have poor water quality.