To spray or not to spray

Information below is relevant until further updates are provided here or on our Supply and Service Updates section

The number of pesticide exceedances in public drinking water supplies in Ireland has decreased significantly since 2017, by more than 50%. Despite these improvements, there was a small increase in the number of exceedances detected last year by Uisce Éireann’s public water supply monitoring programme, with 66 exceedances detected in 2024 from over 34,000 analyses, compared to 52 exceedances in 2023.  While the overall compliance rate remains very high, it is important that there are sustained efforts and vigilance by all stakeholders to protect drinking water quality.

The National Pesticides and Drinking Water Action Group (NPDWAG) reminds users of herbicides and other pesticide products to always take account of the vulnerability of their local drinking water supplies when making decisions about possible use of pesticides and to be aware of how their actions could impact their community's drinking water.

Currently, there are several catchment areas prioritised for action, where Uisce Éireann has detected recurring pesticide exceedances from our monitoring programmes. These include Hacketstown, Co. Carlow, Greenmount, Co. Louth and Foynes Shannon Estuary, Co Limerick. Members of the NPDWAG and local catchment-based focus groups, established to coordinate targeted actions at a local level, are prioritising these areas for further work in 2025. Similar targeted action in recent years in areas such as Belturbet, Co. Cavan and Newport, Co. Mayo has been a success in eliminating pesticide exceedances in those water supplies.

Dr. Pat O'Sullivan, Uisce Éireann's Drinking Water Compliance Senior Manager, emphasises the need for collective action: "Last year, we detected pesticide exceedances 66 times in 22 public drinking water supplies. A concerning trend is the number of exceedances outside the spraying season for certain plant protection products, particularly in winter. We would like to remind users to be mindful of water sources when using pesticides as 1 drop of pesticides can be detected in a stream up to 30 km away.”

Dr. Aidan Moody, Department of Agriculture, Food and the Marine (DAFM) and Chair of NPDWAG, highlights the need for stakeholders to continue to work together and stresses that an integrated pest management approach must be followed, in which the potential to use alternative control methods is fully considered. “We all have a part to play in protecting drinking water quality. 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, make sure that they follow best practice measures to protect water quality. This approach is a win-win for water quality and biodiversity.”

Uisce Éireann and the NPDWAG are urging farmers, greenkeepers, amenity users and domestic pesticide users to carefully evaluate the necessity of using pesticides. Pesticides should only be applied when essential and after considering alternative methods. By minimising pesticide use, we can protect water quality and help to deliver wider environmental benefits. Leaving some areas unsprayed can allow native flowering plant species to thrive, which in turn supports a variety of insects, including bees and other important pollinators.

Farmers and other landholders dealing with the challenge of rushes should note and follow the DAFM guidance on the sustainable management of rushes. This approach is based on the concepts of containment or suppression and aims to minimise the use of pesticides.

If pesticides must be used, the basic steps to reduce risks to drinking water sources and the aquatic environment are:

• Always read the product label carefully and only use product as directed on the label.
• Note that a closed spray period, during which product use is not permitted, is specified on the label for some products (e.g. products containing MCPA). Note also that products containing MCPA are NOT approved for use in weed-wipers.
• Do not use pesticides if rain is forecast in the next 48 hours.
• Make sure you are aware of the location of all nearby watercourses, including drains, wells and springs.
• Comply with either a minimum 3 m no-spray buffer zone, for any watercourse subject to CAP conditionality, OR a larger product-specific aquatic buffer zone specified on a product label, if one has been set. Mark out the required buffer zone from the edge of the river or lake or other watercourse and drainage ditches.
• Avoid spills, stay well back from open drains and rinse empty containers 3 times into the sprayer.
• Store and dispose of pesticides and their containers properly.
• Never fill a sprayer directly from a watercourse or carry out mixing, loading or other handling operations beside a watercourse.
• Never fill/wash a sprayer on concrete or sealed surface areas, where spillage/runoff to drains/watercourses is possible.
• Never leave a sprayer unattended during filling, mixing/agitating, regardless of location.

More information on this can be obtained from your local farm advisor or on the DAFM pesticides website at www.pcs.agriculture.gov.ie/sud/waterprotection

Further guidance:

• DAFM guidance on good practice during sprayer operations is available at www.pcs.agriculture.gov.ie/media/pesticides/content/sud/Guidance%20for%20sprayer%20operations%20updated%20110325.pdf
• DAFM guidance on sustainable rush management is available at www.pcs.agriculture.gov.ie/media/pesticides/content/sud/Managingrushes250320.pdf
• A sustainable rush management graphic is available at www.pcs.agriculture.gov.ie/media/pesticides/content/sud/Managingrushesgraph250320.pdf
• A video on the best practice use and application of products containing MCPA can be viewed on Uisce Éireann’s YouTube channel at https://youtu.be/xQqtZ7jifUs
• Information leaflets on pesticide use are also available to download from the Teagasc website at http://www.teagasc.ie/environment/water-quality/farming-for-water-quality-assap/improving-my-water-quality/protecting-drinking-water-from-pesticides/
• A guide providing 10 easy steps towards responsible pesticide use in public and amenity and garden areas is available at www.pcs.agriculture.gov.ie/media/pesticides/content/sud/Responsible%20Pesticide%20Use%20in%20Public,%20Amenity%20and%20Garden%20Areas%20170823%20180823.pdf
• Uisce Éireann has launched a pilot study in Cavan’s Erne-Larah catchment to encourage farmers to consider the vulnerability of the water supplies to pesticide contamination. This pilot study aims to assist Uisce Éireann with capturing new data and learnings on how different protection measures can improve water quality. To learn more about the project, please visit the dedicated project page at www.water.ie/projects/national-projects/erne-larah/