NI Water issues urgent call to prevent herbicide contamination of water supplies

NI Water is urging farmers, gardeners and land managers across Northern Ireland to take extra care when using plant protection products, particularly during the spring and summer spraying season, to prevent harmful chemicals from entering local rivers and lakes.

With the increased use of herbicides such as MCPA between April and October to control rushes and broadleaf weeds, NI Water is highlighting the risks of contamination to raw water sources.

These watercourses, which supply drinking water to thousands of households, are increasingly under threat from pesticide pollution.

Avoiding Drips and Spills

A key focus of NI Water’s message is the prevention of drips and spills during chemical preparation, application, equipment cleaning and disposal. These spills can be washed off land during heavy rainfall or enter drains inadvertently during handling in the yard.

By taking simple precautions, users can help protect the environment and ensure cleaner water supplies. A spokesperson for NI Water explained:

“By taking precautions to avoid drips and spills it reduces the amount of plant protection products being used in domestic, amenity or agriculture sites getting into many local rivers and lakes where raw water is extracted from catchment areas to then treat as drinking water.”

Challenges with MCPA

Becca Allen, Catchment Officer at NI Water, highlighted the recurring presence of MCPA in water sources:

“Our data shows MCPA commonly appears in our watercourses during the main application seasons of April to October. So we know that at this time of the year many farmers will be spraying rushes or other weeds in grasslands, or domestic users will be treating weeds in their gardens. This is frequently done using products containing the broadleaf herbicide MCPA, which is currently one of the main challenges to protecting raw water quality in NI.”

Ms Allen continued:

“It is very soluble in water and lingers in the surface water for a long time making it challenging and very costly for NI Water to remove at the water treatment stage.

“Despite these challenges, NI Water works hard to remove substances like MCPA to provide safe and wholesome drinking water for our customers, and in order to comply with current drinking water standards. However, it would be preferable that plant protection products don’t get into our rivers and lakes in the first place.”

She also reminded users that chemical loss is not only an environmental risk but a financial one:

“It is also important to remember that MCPA loss from the land represents a financial loss to the farm business in wasted product. It poses a risk to the water environment and the plants and animals that depend on it. We all need to work together to protect our precious drinking water resources.”

Partnerships and Progress

NI Water’s efforts are strengthened by its membership in the Water Catchment Partnership, a coalition including the Ulster Farmers’ Union, DAERA, CAFRE, and the Voluntary Initiative. Since 2013, this collaborative approach has yielded promising results, with a marked reduction in MCPA levels in affected catchments — though more work remains.

Among the most effective initiatives has been NI Water’s ‘Rush Solution Without Pollution’ programme.

This trial project has supported more than 300 farmers in counties Armagh, Tyrone, Antrim and Derry~Londonderry, offering a free weed-wiping service as an environmentally safer alternative to traditional boom spraying with MCPA.

Additionally, the Source to Tap Pilot Land Incentive Scheme, funded by the EU’s INTERREG VA Programme and supported by DAERA and Ireland’s Department of Housing, Local Government and Heritage, achieved a 25% reduction in MCPA levels in raw water in the Derg catchment.

The initiative provided 100% funding for farmers to switch to weed-wiping methods upstream of the Water Treatment Works.