A major new analysis by the Wastewater Infrastructure Group (WIG) warns that constraints in Northern Ireland's wastewater network are now a significant drag on housing delivery, investment, regeneration and long-term economic growth.

The report, Wastewater Constraints and the Cost of Delay in Northern Ireland: An Economy with the Brakes On, was unveiled at The Long Gallery, Parliament Buildings, Stormont, on Wednesday 1 July 2026. As a co-sponsor of the report, the Chartered Institute of Housing (CIH) attended the launch.

It estimates that if current bottlenecks persist, Northern Ireland's economy could be £10.9 billion smaller in annual GVA by 2040 than it would be if the necessary infrastructure capacity were delivered.

Under the modelling, households would on average be £2,750 per year worse off, with the impact increasing over time from £325 per household in 2028, to £3,085 in 2035 and £5,500 in 2040.

The authors call for a funded, multi-year approach to wastewater infrastructure, including strategic investment in NI Water and legislation to deliver Sustainable Urban Drainage Solutions. They also recommend using voluntary developer contributions to supplement investment and establishing a clearer, long-term funding model to support housing, economic growth and environmental improvement.

The analysis draws on an economic model prepared by Andrew Webb, lead economist at trade and investment advisory firm OCO Global, combined with research and case studies from independent infrastructure and built environment advisors Turley.

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The report highlights that around 55,000 homes are currently understood to be held back by wastewater capacity constraints. It adds that the effects reach beyond housing into construction, regeneration, employment land, town centre growth, private investment and environmental recovery.

While acknowledging recent progress — including approximately £30 million of additional monitoring round funding that has helped unlock almost 5,300 new homes since autumn 2024 — the report cautions that current interventions are not sufficient to meet the scale of the challenge.

WIG's membership includes the Chartered Institute of Housing, NI Chamber, Construction Employers Federation, Northern Ireland Federation of Housing Associations, Manufacturing Northern Ireland, Northern Ireland Retail Consortium and the Institute of Directors (NI).

The group says wastewater capacity is not simply a utility or environmental matter, but a core economic infrastructure challenge for Northern Ireland.

Mark Spence, Chief Executive of the Construction Employers Federation, speaking on behalf of the Wastewater Infrastructure Group, said: "Wastewater infrastructure is now one of the most significant constraints on Northern Ireland's construction sector. This is not simply about pipes and treatment works. It is about whether we can build the homes people need, support business growth, regenerate our towns and cities, and protect our environment.

"The report shows that the cost is real and growing. Around 55,000 homes are understood to be impeded by some level of wastewater constraints, while our modelling indicates that Northern Ireland's economy could be £10.9 billion smaller in 2040 if we continue on the current path where the funding received for wastewater infrastructure is less than that established by the Utility Regulator."

Justin Cartwright, Northern Ireland Director at the Chartered Institute of Housing, concluded: "Northern Ireland can continue to manage constraint – leaving thousands on housing waiting lists - or it can choose recovery and growth. With the right funding model, clear delivery plan and political commitment, wastewater infrastructure can become an enabler of growth, housing, environmental improvement and regional balance."

Suzanne Wylie, Chief Executive of NI Chamber, added: "The cost of wastewater constraint to Northern Ireland's economy is already being felt through delayed homes, deferred investment, higher housing pressures, and weaker confidence in delivery, but what this report demonstrates is the extent to which it may limit the scale of our growth as a region. That should focus minds.

"We support the progress that has been made, including funding allocations that have helped unlock new homes in parts of Northern Ireland. However, the scale of the challenge now requires cross party agreement for a strategic, long-term, and properly funded response – meeting the capital requirements set by the regulator established through the price control mechanism that establishes the funding requirements for NI Water."