Pesticides were detected in drinking water in Co Cavan on two occasions last year.
The exceedances of drinking water regulations for a substance called MCPA were found in the public water supply in Belturbet.
MCPA, which is present in some herbicide products, is the most commonly detected pesticide in drinking water.
Uisce Éireann says the Belturbet public water supply is vulnerable to run-off from land because it uses raw water from the River Erne.
However, it said the levels detected were not a threat to public health.
Thomas Gibbons, Regional Drinking Water Compliance Specialist, said the pesticides were noted in the Belturbet supply following routine sampling.
"While our consultation with the HSE has concluded that the levels we are detecting do not represent a threat to public health, they are still however undesirable in drinking water and it is therefore imperative that users of pesticides are mindful of best practice when using herbicides or pesticides and seek out alternatives," he said.
Pesticide exceedances in Cavan doubled from one in 2021 to two last year.
The presence of pesticide levels above the allowed value indicate there may have been careless or excessive use of a product in the drinking water catchment area.
Uisce Éireann is appealing to the public to consider the vulnerability of their local drinking water supply to pesticide contamination and think about using alternatives to pesticides when gardening, farming and maintaining sports grounds.
"Uisce Éireann and the NPDWAG (the National Pesticides and Drinking Water Action Group ) are asking the farming community, greenkeepers, grounds keepers, and also domestic users of pesticides, to consider in each case whether they need to use pesticides at all.
Pesticides must only be used where strictly necessary and only after the possibility of using other control methods has been carefully considered.
Minimising pesticide use not only helps to protect water quality but also has multiple wider environmental benefits.
Dr Aidan Moody, DAFM and Chair of NPDWAG said that users of pesticides must always consider the possibilities for alternative control methods in the first instance and if the application of pesticides is considered essential, to make sure that they follow best practice measures to protect water quality.
