City Hall has funded a dedicated enforcement officer to work within a West London council in a new trial intended to enforce action on water‑polluting misconnections. The move was reported on 4 September 2026. Misconnections occur when wastewater appliances are wrongly linked to surface‑water drainage, allowing waste to reach waterways. The development is relevant for residents across the River Brent catchment, which the Mayor’s Clean Rivers and Waterways Plan identifies as a priority area for resolving incorrectly plumbed pipes.
The pilot places an officer inside a local authority to focus on properties and developments found to be misconnected. It aligns with City Hall’s wider approach set out in the official plan, which singles out the Brent catchment in west and north‑west London for early attention. The arrangement concentrates capacity within a council setting so that investigations and follow‑up can be pursued under existing powers, working alongside partners responsible for drainage and river health.
Why the River Brent catchment is in focus
The official plan names the River Brent catchment as a priority area, spanning Barnet, Brent, Harrow, Ealing and Hounslow. The catchment drains densely populated neighbourhoods and includes urban streams that are sensitive to what enters the surface‑water network. Directing early investment to strategic locations is a stated part of the city approach, intended to support visible progress as partners work to improve conditions in rivers and streams used for recreation and nature.
City Hall’s Clean Rivers and Waterways Plan sets a five‑year ambition for partners to fix pollution‑causing misconnections at more than 200 sites. It also directs early funding to ten strategic waterway locations to accelerate activity. Embedding a dedicated officer within a council sits alongside that programme, providing a focused point for case management and coordination with other organisations involved in identifying and rectifying misconnections.
What misconnections are, and who must fix them
A misconnection happens when wastewater appliances are incorrectly hooked up to surface‑water drains rather than the foul sewer, allowing waste to reach rivers. Such misconnections are illegal and the property owner is responsible for putting them right. They are often accidental, arising from building or plumbing errors rather than deliberate acts. Once identified, the duty to remedy sits with the owner, and council enforcement is intended to help ensure issues are addressed.
Surface‑water drains are designed to carry rainwater. When sinks, washing machines or toilets are wrongly connected to those pipes, the outflow can bypass treatment works and enter local watercourses. The council‑based officer model is designed to help progress investigations and facilitate the steps required to correct misconnections, working with relevant partners so that fixes are completed.
Evidence of the problem and progress to date
Information released in 2024 identified seven blocks of flats in north and west London, involving at least 100 homes, where misconnections were affecting the Crane and Brent rivers. Thames Water said that three of those developments had since been resolved. The remaining identified sites were two in Barnet and two in Harrow, while three locations in Ealing had been fixed. Exact property locations were not published.
Those figures provide a snapshot rather than a full tally of misconnections in the Brent and neighbouring catchments. The citywide plan anticipates more than 200 pollution‑causing misconnection sites will need to be rectified over the next five years, underlining the scale of the task and the need for coordination between councils, water companies and developers. The trial officer arrangement is consistent with that overall programme by focusing resources at local level on investigations and enforcement related to misconnections.
The trial will operate within one West London council. Alongside this, the Clean Rivers and Waterways Plan sets out early investment at ten strategic locations to support delivery. Throughout, the responsibility for correcting an identified misconnection remains with the property owner, with councils, utilities and other partners working within their roles to facilitate compliance and protect river health in priority areas, including the River Brent catchment.
