It's the first time in three years that traces have been detected in Offaly or Laois.
Pesticides have been detected in public drinking water supplies in two midlands towns.
Irish Water noted exceedances of the herbicide MCPA in Rhode.
While traces of the glyphosate have also been found in Borris-in-Ossory's drinking water supplies.
It's the first time in three years that pesticides have been detected in Offaly or Laois.
No traces have been found in drinking water in Westmeath.
Irish Water is urging gardeners and farmers to consider whether pesticide use is necessary, especially in the River Boyne and Nore catchment areas.