Pesticides play an important role in farming and land management, but they can also pose serious risks to water quality.
Uisce Éireann has recently reported a sharp rise in the level of pesticides in waterways across Ireland.
In this blog, we’ll look at the health concerns of pesticides, how contamination happens, and what actions are being taken to protect our water.
Table of Contents
Uisce Éireann Finds Pesticides in Water
Pesticides are chemicals used to protect plants by killing insects, weeds, and other pests. They’re used large-scale in farming, forestry, and transport industries. They’re also often used on a smaller scale in private gardens, parks, and golf courses.
As part of their public water supply monitoring programme, Uisce Éireann tested over 34,000 water samples last year. They found pesticide exceedances in 66 cases – a rise of more than 25% from the previous year.
Recurrent issues were noted specifically in parts of counties Louth (River Dee), Carlow (Hacketstown), and Limerick (Foynes Shannon Estuary).
How Pesticides Contaminate Water
Most public drinking water in Ireland comes from rivers, lakes, and streams. Pesticides can enter these waters in different ways:
- Spraying too close to water
- Rain washing chemicals off the land
- Wind carrying pesticide spray into water
- Leaks during storage or disposal
Once in water, even small amounts of pesticide can go far. These pesticides harm aquatic ecosystems and human health (if they make their way into public water supplies).
Actions Being Taken & Advice
In high-risk areas, catchment-based focus groups are now active and will guide targeted work in 2025. These groups bring together local experts, farmers, and community members to reduce pesticide risks and protect water at the source.
Previous efforts in Cavan and Mayo have already helped remove pesticides from water, showing that focused action can work.
Uisce Éireann encourages using other methods to control weeds instead of chemicals. This advice comes at a time when pesticide bans across the EU are becoming more common.
If pesticides must be used, follow these important steps:
- Read and follow the product label carefully
- Avoid spraying if it will rain within 48 hours
- Know where nearby streams, drains, wells, or springs are located
- Never fill a sprayer directly from a water source.
Public Statement & Resources
Dr Aidan Moody, Chair of the National Pesticides and Drinking Water Action Group (NPDWAG) said:
“I want to acknowledge the good work done by farmers and other users of pesticides to protect water quality. There needs to be a sustained effort by all stakeholders to make further progress. Users of pesticides must make sure that they follow best practice measures to protect water quality.”
Here are some helpful, free resources designed to help you use pesticides safely:
- Teagasc website: Leaflets with tips on safe pesticide use
- 10-Step Guide: Easy steps for responsible use in gardens and public spaces
- Uisce Éireann’s YouTube Channel: A video guide to using MCPA (herbicide) correctly ⤵
Testing for Pesticides in Water
As Dr Pat O’Sullivan of Uisce Éireann says: “One drop of pesticide can be detected in a stream up to 30km away.” Because pesticides can travel far in water, it’s often hard to tell where they came from or what type was used.
As a result, lab testing is often essential to help identify the pesticide type and where it came from.
Southern Scientific is Ireland’s only lab with full INAB ISO accreditation to test for all pesticides on the Uisce Éireann and EPA lists. Partnering with a trusted lab gives the best chance to detect and deal with pesticides in water early.
