The Office for Environmental Protection (OEP) has announced it is investigating the Department for Infrastructure (DfI), the Department of Agriculture, Environment and Rural Affairs (DAERA) and the Utility Regulator over the regulation of sewage discharges into Belfast Lough.

The investigation will examine the regulation of discharges of untreated sewage from Wastewater Treatment Works (WWTW) and Combined Sewer Overflows (CSOs).

The focus of the investigation is on DfI, DAERA and the Utility Regulator because they are the primary regulators and play key roles in enforcing NI Water’s own responsibilities in relation to sewage discharges.

The investigation will determine whether the authorities have failed to comply with environmental law in their respective duties of regulating how untreated wastewater, that includes raw sewage, is discharged into Belfast Lough and its surrounding rivers.

Natalie Prosser, OEP Chief Executive Officer (CEO), said:that NI Water is not in scope of this investigation as the OEP’s role is not to step into the shoes of the regulators, but to ensure that they themselves are fulfilling their legal duties. However, the OEP would be speaking to NI Water and requesting information to support this work.

Commenting that nature is under unsustainable pressure in Northern Ireland, and one of the biggest issues is how wastewater is managed, she said:

“We’ll be looking at whether the Utility Regulator and DfI have met their duties to take necessary enforcement action, where Northern Ireland (NI) Water may not be fulfilling their own responsibilities for sewage discharges. For DAERA, we’ll examine whether it has set and updated the conditions that allow sewage overflows to spill in line with legal standards.

“Although our investigation will focus on Belfast Lough, we know similar wastewater and sewage issues exist at other rivers and lakes. Our interest is in driving improvement across the wider regulatory system. What we find in this investigation will be relevant across Northern Ireland.”

If the OEP finds failures to comply with the law, the aim of the investigation will be to improve compliance and regulation across the wastewater system leading to long-term water quality improvement.

The OEP action follows on from its report into the causes of Northern Ireland’s nature loss last year (2024). It confirmed that agriculture and wastewater are the two largest contributors to water pollution, due to excess nutrients from fertilisers, animal waste (coming from imported animal feeds) and sewage. Excess nutrients is a major cause of the blue green algal blooms that have blighted Lough Neagh in recent years.

Natalie Prosser continued:

“We have been clear that nutrient pollution from both, agricultural and wastewater sources, need to be tackled to better protect and improve the water in lakes and rivers.

“This is a complex problem with no quick fixes, but our investigation will contribute to the work already underway in this area, so government and other decisionmakers can be targeted and effective in driving much-needed improvements in water quality.”

If failures to comply with environmental law are found the OEP will look to resolve these by working constructively with the authorities involved to achieve a positive outcome. If no agreement can be found the OEP can take court action.

This investigation has been initiated by the OEP - it is the OEP’s fourth investigation in Northern Ireland.

NI Water commits to working with Office of Environmental Protection

Acknowledging the Office for Environmental Protection’s (OEP) ongoing investigation into the regulation of sewage discharges into Belfast Lough. NI Water said that while it is not the subject of the investigation, the company remains committed to full cooperation with the OEP and all relevant authorities, and will continue to provide any information required under its statutory duties.

NI Water has consistently highlighted the urgent need for sustained investment in wastewater infrastructure to address long-standing challenges across Northern Ireland. In October 2024 NI Water published the ‘Story of Belfast Lough’ to explain how the wastewater system, water quality and capacity constraints have reached this point and the importance of the decisions ahead.

The water company commented:

“We also wish to clarify that the Living With Water Programme (LWWP), which aimed to address many of these issues, was paused due to funding constraints. NI Water will continue to engage constructively with the Department for Infrastructure, the Utility Regulator, the NI Environment Agency and other stakeholders to support improvements in environmental compliance and governance.

“In late 2023 DfI announced that it had initiated a review of the Living With Water Programme for Belfast to determine if it should continue to be implemented, and under what level of funding.

“NI Water and the other LWWP Partners (DEARA, NIEA, Belfast City Council and the Utility Regulator) have each actively participated in the review process and now await direction on the level of funding to be provided so that NI Water can assess if any of the proposed LWWP NI Water Major Projects for Greater Belfast will be able to proceed as had been planned in 2021.”