Farmers and landowners are reminded to use best practice when spraying pesticides, to protect drinking water supplies.
Irish Water says pesticides have been detected in drinking water supplies across Ireland, which sometimes exceed the permitted limit.
Newport in Co Mayo is one of 6 areas of the country of particular concern, where pesticides are persistent.
The Newport Public Water Supply, which sources its water from Newport River, is currently on the EPA's Remedial Action List, due to persistent exceedances for MCPA and Glyphosate over a 4-month period last year.
Irish Water, working with a range of organisations involved in the National Pesticides and Drinking Water Action Group, says great care must be taken to protect drinking water supplies wherever pesticide use is considered necessary.
While pesticides do not pose any immediate risk to health, Irish Water says a single drop of pesticide is enough to breach the drinking water limit in a small stream for up to 30 kilometres, which highlights the level of care needed to protect drinking water sources.