It only takes one drop of pesticide to impact a drinking water source. Uisce Éireann, in partnership with the National Pesticides and Drinking Water Action Group (NPDWAG), have issued the warning as the 2026 spraying season gets underway.

Pesticide exceedances have reduced by more than 50% over the past nine years since the action group began. However, the latest monitoring data shows that a small number of exceedances continue to occur.

This highlights that it is important for users to adhere to best practice and responsible use across both rural and urban areas.

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There was a total of 69 exceedances of the statutory limits for pesticides in the Drinking Water Regulations detected across 24 public water supplies in 2025.

These results were drawn from over 45,000 analyses carried out nationwide by Uisce Éireann’s monitoring programme and shows a very high overall rate of compliance.

The commonly used herbicide MCPA was linked to 49 of the non-compliant findings.

Water supplies that have been prioritised for action in 2026 due to reoccurring exceedances include: Greenmount in Louth, Longford Central in Longford and the Foynes/Shannon Estuary supply in Limerick.

Local collaboration

Many other water supplies displayed significant improvement in 2025 as a result of targeted engagement, local collaboration and consistent best practice implementation.

The Hacketstown water supply in Carlow, the Belturbet water supply in Cavan and the Newcastle West water supply in Limerick all recorded strong improvements in 2025, each showing significant improvement compared to previous years.

'Strong progress'

“While we continue to see strong progress since the NPDWAG was established, the 2025 results highlight that there are still some instances of pesticides entering water sources,” Dr Aidan Moody chair of the National Pesticides and Drinking Water Action Group stated.

“We also want to acknowledge the continued commitment of the farming community, who have played a vital role in reducing exceedances in recent years. Their willingness to adapt, follow best practice and work proactively with local partners is making a real and measurable difference to protecting our drinking water.

“We ask all pesticide users to always carefully consider whether pesticide use is necessary and, where it is, to follow best practice in every instance. Every responsible choice, whether selecting an alternative control method where possible or avoiding pesticide use in unsuitable weather conditions such as when rain is forecast helps safeguard drinking water across our communities,” he said.

“Local action is delivering real improvements, and we are encouraging all pesticide users to keep up this positive momentum as we enter the 2026 spraying season,” Dr Patrick O’Sullivan of Uisce Éireann commented on the call to action.