A high level of pesticides was found in a sample from the water supply for Kilkenny city last year.
Irish water says their monitoring programme picked up one instance where the level of MCPA was higher than allowed at Kilkenny City Troyswood public water supply in 2021.
MCPA is present in many common products used to control thistles, docks and rushes and is still the most commonly detected pesticide in drinking water sources.
It’s the only time the levels of pesticide exceeded allowed levels in either Carlow or Kilkenny in the past two years.
The HSE confirmed there was no danger to public health.
But Irish Water is asking users of any herbicide or pesticide products to continue to consider the vulnerability of their local drinking water supplies to pesticide contamination.