NI Water has issued an update to Belfast City Council, warning that long-term underinvestment in the city's wastewater infrastructure is now a primary bottleneck for new housing and economic growth.

In a recent presentation to Councillors, representatives from the utility provider detailed how significant reductions in capital funding during the current Price Control period (PC21) have stalled critical projects across the Greater Belfast area.

The scale of the challenge within the city's network is immense. NI Water revealed that out of 192 storm overflows in Belfast, 156 are currently classed as unsatisfactory. This not only heightens the risk of local pollution but also means many proposed housing developments in the city are currently "on hold" because the existing system cannot accommodate new connections without major upgrades.

Dr Stephen Blockwell, Head of Investment Management at NI Water, emphasised that a fully funded system is vital for the city's future.

He stated: "Without urgent and sustained investment in the wastewater system, the city faces ongoing pollution risks, and constraints on development." The presentation also turned to the environmental health of Inner Belfast Lough. Data suggests that wastewater discharges are a significant contributor of bacteria and nitrogen entering the Lough, leading to harmful algal blooms. Unlike the issues facing Lough Neagh, the primary cause of pollution in Belfast Lough is identified as infrastructure-related, which NI Water maintains can only be solved through substantial capital works.

While NI Water is currently progressing around 30 schemes in the city—valued at approximately £91 million—the work is largely focused on essential maintenance rather than the capacity upgrades needed for growth.

The flagship Living With Water Programme (LWWP), a £1.9 billion long-term plan to modernise Belfast's drainage and prevent flooding, has seen major elements paused due to recent funding cuts.

Looking toward the next Price Control period (PC28) starting in 2028, NI Water estimates that £7 billion is required across Northern Ireland to address capacity issues and environmental resilience. Dr Blockwell concluded that while "short-term injections of funding" can help in the immediate term, only a stable, multi-year funding settlement will allow Belfast to meet its housing and economic targets.