NI Water is continuing to deliver important local benefits through its multi-million-pound ‘Stormwater Separation Programme’, helping to reduce the risk of out of sewer flooding, improve environmental performance and create extra capacity within the wastewater network to support new homes and economic growth across Northern Ireland.

Over the past three years and working collaboratively with their appointed framework partners, Atkins Réalis, AG Wilson Civil Engineering and CivCo, NI Water has committed £5 million to stormwater separation projects. This includes investigations to assess and prioritise where the combined systems can be separated to achieve maximum benefit followed by the installation of new stormwater infrastructure.

Speaking about the strategic approach, Robert McLean, Senior NI Water Project Manager said: “This long-term investment by NI Water is helping to modernise wastewater infrastructure in areas facing network constraints, creating additional capacity to support sustainable development while improving resilience for local communities during periods of heavy rainfall.

“Much of the wastewater network serving residents and businesses across Northern Ireland is a combined system, meaning that stormwater from gutters, drainpipes and gullies is collected in the same pipes and transferred to a wastewater treatment works before being cleaned and returned safely to the environment. Stormwater does not require treatment and therefore removing it from the combined network not only delivers efficiencies for NI Water but in certain cases, it can unlock the potential for development and economic growth.

“The Stormwater Separation Programme is delivered in carefully planned stages, beginning with extensive investigations during the early stages. This includes CCTV surveys and detailed assessments of existing drainage systems to identify and resolve historic misconnections before construction begins. This ensures only genuine stormwater is diverted from the combined sewer network, maximising environmental and operational benefits.

“Since the programme began in 2023, NI Water has removed over 166,000 square metres of surface water drainage from the combined sewer network. This has not only significantly reduced the pressure on the existing wastewater infrastructure but has created extra capacity for around 600 new homes across NI.

“Although there is short-term impact through the installation of dedicated stormwater infrastructure, communities in Derry/Londonderry, Newry, Ballymena, Portadown, Belfast, Newtownabbey, Antrim and Coleraine have benefitted from the long-term benefits of the Stormwater Separation Programme through increased wastewater network resilience, better environmental protection and improved capacity.

“This ongoing investment reflects NI Water’s commitment to delivering essential infrastructure improvements that support local communities, protect the environment and enable long-term regional growth across Northern Ireland.”

Ends

Notes to editors:

Since April 2021, NI Water has carried out 17 stormwater installation and investigation projects at the following locations:

 

STORM SEPARATION PROJECT LOCATIONS

St. Patrick’s Avenue Coleraine

Moores Walk Derry/Londonderry

Ashgrove Park Newry

Loughries Newtownards

Dominican Court Newry

Princess Way Portadown

Oriel Close Antrim

Abbeyville Street Newtownabbey

Fernagh Drive Newtownabbey

St Catherines Court Armagh

Seagoe Gardens Portadown

Moat Road Ballymena

Upper Princess Street Ballymena

Culmore Road Derry/Londonderry

Culmore Road Derry/L’Derry Part 2

Fanad Drive Derry/L’Derry

Victoria Gardens Lurgan

By reducing stormwater entering the combined sewer system at these locations, NI Water is helping to:

• Reduce the risk of localised out-of-sewer flooding during heavy rainfall
• Improve environmental compliance and water quality outcomes
• Increase resilience across wastewater treatment works
• Unlock capacity to support new housing and local economic development
• Future-proof wastewater infrastructure for growing communities

The programme includes a range of targeted improvements, including:

• Diverting stormwater away from combined sewers into dedicated storm drainage systems
• Identifying and correcting historic misconnections
• Reducing surface water loading on wastewater treatment works
• Improving compliance with environmental discharge standards