NI Water urges farmers to protect waterways as slurry season nears closure

As the slurry season draws to a close on 15 October 2025, NI Water is reminding farmers across Northern Ireland to take extra care to protect water resources when spreading slurry, manures or fertilisers in the coming weeks.

The utility has urged farmers to plan the timing and placement of organic manures and fertilisers carefully to reduce the risk of pollution to local rivers, lakes and watercourses — particularly as the weather turns wetter.

According to NI Water, soils with poor drainage and steep slopes are especially vulnerable to runoff during rainfall. Even a short downpour can carry high levels of phosphorus into waterways, causing nutrient pollution that can damage aquatic ecosystems.

Peter Quinn, NI Water Catchment Officer, said:

“Care in timing and placement of slurry, manure and fertiliser is vital to minimise the potential for loss from land to water. If slurry is spread on poor, very wet ground or during or just before wet weather conditions, it can run off the land; this results in valuable nutrients ending up in our watercourses.

“Abstracting this from our water is difficult and expensive to treat, however NI Water must do this in order to provide the high-quality drinking water we all expect.”

Closed period begins 15 October

The closed period for spreading organic manures — including slurry, poultry litter, sewage sludge and abattoir waste — runs from 15 October 2025 to 31 January 2026.

Farmyard manure must also not be applied between midnight 31 October 2025 and 31 January 2026.

As the season ends, farmers are reminded that organic manures (including dirty water) must not be spread:

• Within 250m of a borehole used for public water supply

• Within 50m of a borehole, spring or well

• Within 30m of lakes

• Within 15m of a waterway other than lakes (reduced to 5m when using LESSE equipment)

• On waterlogged, flooded, frozen or snow-covered ground

• If heavy rain is forecast in the next 48 hours

• On steep slopes (more than 20% incline on grassland, or 15% on other land)

Protecting water quality

NI Water is encouraging farmers to use nutrient management planning and DAERA’s online tools to calculate their farm’s phosphorus balance and nitrogen loading.

Practical steps include checking farmyards for potential slurry runoff, preventing cattle access to rivers, and reducing phosphorus inputs by meeting crop requirements through manures rather than chemical fertilisers.

The company also highlights that eliminating chemical phosphorus fertiliser not only benefits the environment but can also help farmers save money.

NI Water says following the Nutrients Action Programme is a key step in farming efficiently while protecting water quality for everyone.