The OEP has sent each of the public authorities a decision notice setting out its findings and the steps that it considers should be taken to put matters right. The public authorities now have two months to respond and confirm whether they are going to take those steps. Failure to do so could result in court action.

Helen Venn, the OEP’s Chief Regulatory Officer, said:

“During our investigation into the regulation of network CSOs by the three public authorities and intensive engagement with those bodies, we have seen positive steps taken to address the issues identified.

“These steps build on the production of the Storm Overflow Discharge Reduction Plan (SODRP) and include Defra's recent consultation on updated guidance for regulators and water companies, as well as the EA's consultation on an updated Storm Overflow Assessment Framework (SOAF), which includes permit conditions relating to spills from CSOs. Additionally, Ofwat has issued draft enforcement orders to three water companies and continues its investigations into all other water companies.

“The core issue identified in our investigation is the circumstances in which the regulatory system allows untreated sewage discharges to take place. We interpret the law to mean that they should generally be permitted only in exceptional circumstances, such as during unusually heavy rainfall. This is unless an assessment of the CSO concludes that the costs to address the issue would be disproportionate to the benefits gained. While the public authorities are now taking steps to ensure their approaches are aligned and reflective of the law, we have found that this has not always been the case. The decision notices formally clarify what we have concluded is required.

“We will decide next steps when we have considered the responses to these decision notices. That could include court action.”

Defra findings

The OEP investigation has concluded that there have been three failures to comply with environmental law by Defra - failing to take proper account of environmental law by:

• Drafting guidance for water companies and regulators which did not reflect the true legal extent of sewerage undertaker duties
• Failing to amend or replace the guidance after a relevant Court of Justice of the European Union (CJEU) decision in 2012
• Misunderstanding its legal duty under environmental law to make enforcement order
• Failing to exercise its duty under environmental law to make enforcement orders
• Failing to discharge its duty to secure compliance with environmental law relating to emissions controls

The recommended steps to remedy, mitigate or prevent reoccurrence of the failures include revising the guidance, ensuring delegated responsibilities are carried out properly, agreeing Memorandums of Understanding (MoUs) with the EA and Ofwat and ensuring that permits for CSOs are amended appropriately.

In relation to the first failure identified above, the OEP acknowledges Defra's recent consultation on updated guidance for regulators and water companies and awaits the outcome of this process. The OEP considers that the third failure listed above ended on 31 December 2020 following the UK’s withdrawal from the European Union.

Ofwat findings

The OEP investigation has concluded that there have been two failures to comply with environmental law by Ofwat:

• Failing to take proper account of environmental law with regards to duties on sewerage companies and its duty to make enforcement orders.
• Failing to exercise its duty under environmental law to make enforcement orders.

The recommended steps to remedy, mitigate or prevent reoccurrence of the failures include updating enforcement guidance, agreeing and publishing a new MoU with the EA, ensuring relevant responsibilities are carried out properly and making sure that appropriate assessments have been carried out on CSOs and time-bound plans are in place for any improvement schemes to be implemented.

The OEP considers that Ofwat's approach now takes proper account of environmental law and that the first failure identified above is no longer ongoing. Regarding the second failure, the OEP acknowledges the draft enforcement orders proposed by Ofwat and awaits the outcome of its consultation process and ongoing investigations.

Environment Agency findings

The OEP investigation has concluded that there have been three failures to comply with environmental law by the EA:

• Failing to take proper account of environmental law in devising guidance relating to permit conditions
• (As a result of the point above) setting permit conditions that were insufficient to comply with environmental laws
• Failing to exercise permit review functions in relation to discharges from CSOs

The recommended steps to remedy, mitigate or prevent reoccurrence of the failures include updating the Storm Overflow Assessment Framework and any guidance relating to CSO permit setting, agreeing MoUs with Defra and Ofwat, ensuring CSO permits comply with the appropriate regulations and assessment findings.

In relation to the first failure identified above, the OEP acknowledges the EA’s recent consultation on an updated SOAF and awaits the outcome of this process.

The OEP launched an investigation into the roles of Ofwat, the Environment Agency and the Defra Secretary of State in the regulation of combined sewer overflows (CSOs) in England in June 2022. The investigatio was focused on ‘network CSOs’ which are overflows on the sewerage network rather than those found at sewage treatment works.

The OEP investigation was launched in response to a complaint received by Salmon & Trout Conservation UK, now known as WildFish.