An Environmental Information Request (EIR) has uncovered that over 2,000 properties in London are unlawfully discharging untreated sewage straight into rivers due to drainage errors.

In the last five years, Thames Water has reported 2,294 instances of drainage misconnections across various London properties, as highlighted in the EIR filed by the Local Democracy Reporting Service.

These misconnections occur when waste pipes are improperly linked to the surface water system, and they result from poor plumbing practices rather than the actions of water companies. Such issues often escape the notice of inspectors.

The environmental organization Clean Up River Brent has emphasized the dire implications of this issue, pointing out that the sewage is “damaging the fundamental components of aquatic ecosystems.”

Ben Morris, the founder of Clean Up River Brent, remarked that these misconnections pose a “catastrophic threat to nature,” yet rectifying them proves to be challenging.

He stated: “By allowing sewage—including waste from toilets, showers, and washing machines—to flow into rivers, we are damaging the essential elements that support aquatic life.

“Who would want to live near or visit a foul waterway devoid of life and joy for both wildlife and people?

“These errors often go unnoticed by building inspectors and are typically identified only through the efforts of volunteers who see polluted water entering a river.”

In 2019, the Department for Environment, Food & Rural Affairs (Defra) estimated that between 150,000 and 500,000 households across the UK might have some type of misconnection.

It is the property owner’s duty to address these misconnections.

Mr. Morris pointed out that standard building surveys conducted at the time of purchase often miss these issues, leading new homeowners to encounter unexpected problems.

He further noted: “Due to costs and convenience, owners frequently avoid or refuse to carry out necessary repairs. While local authorities can enforce the law, they are not obliged to do so, and many fail to take action.

“As a consequence of these failures, the number of misconnections in London appears to be increasing, further polluting our rivers.”

Though misconnections are against the law, water companies lack the authority to compel property owners to rectify them.

They can collaborate with homeowners and local councils to encourage voluntary fixes but require support from local governments to legally address unresolved cases.

A representative from Thames Water stated that misconnected pipes significantly impact the environment.

“Most of these misconnections are made unintentionally, yet responsibility lies with the property owner, which is why we advise landlords or developers to ensure their connections are made correctly,” they explained.

“We have initiatives in place to identify and investigate misconnections, and we also invest in local projects throughout our service area.”

Mr. Morris argued that builders and inspectors should be held accountable for mistakes they either make or overlook.

He suggested that councils should employ specialists to enforce corrective measures.

A spokesperson for London Councils, which represents the city’s boroughs, acknowledged that misconnections are a “persistent challenge.”

“Addressing misconnections requires a variety of measures, with adherence to building regulations being a crucial aspect,” they stated.

“London’s boroughs face significant resource constraints, yet they continue to collaborate with partner organizations and their communities to address this issue, including taking enforcement actions when necessary.”

As part of statutory drainage and wastewater management plans established by the Department for Environment, Food & Rural Affairs, water companies will coordinate with local authorities and other stakeholders to assess the risks associated with misconnections and formulate strategies for managing them.