Raw sewage from some new-build developments is being flushed directly into rivers due to apparent blunders during construction.
Seven housing developments in north and west London, amounting to at least 81 homes but likely over 100, are known to be flushing sewage directly into rivers that flow into the Thames, an Environmental Information Request (EIR) has found.
But because that request was limited to a small area, as it was submitted by a campaign group overseeing only the River Brent and River Crane. They believe it's 'highly likely' the problem is widespread in London and the UK.
To compound things, neither local councils, Thames Water or the Environment Agency appears to be taking responsibility for fixing the problem, despite some people having been aware of the sewerage “misconnection” for years. In some cases it appears property owners are being left to sort out the issue but with no legal requirement to do so.
Environmental charity The Friends of the River Crane Environment (FORCE) submitted the EIR to Thames Water after being made aware of at least one block of flats where all the sewage is going into the river rather than to the sewage works, as the plumbing works are connected to the surface water drain system.
The response revealed seven developments that are discharging all their waste water into the Crane and Brent rivers, in what FORCE called a 'major shock'.
They said it is turning the rivers “into sewers”, and risks killing the wildlife, leaving the rivers “effectively dead”.
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FORCE Trustee Rob Gray said: "We were appalled at the extent of this pollution problem and by the approach shown by the developers and/or freeholders - in first allowing this gross misconnection failure to be constructed, then failing to resolve it for up to six years, and finally, in at least one case, apparently seeking to pass the costs of repair on to their leaseholders."
Of the seven developments, three are in the London Borough of Barnet, two are in Ealing, and two in Harrow - five of which are discharging sewage directly into the River Brent. The EIR - a request for recorded information held by a public authority about the environment - shows that Thames Water has known about the misconnections for a while, including one 14-home estate in Ealing which the company has been aware of since 2018. Others were first discovered in 2021, 2023, and 2024 respectively.
Four of the developments equate to 81 homes though Thames Water admits it doesn't even know how many homes are in the other three. The largest development of the ones it does have the number for has 30 homes in it.
Brent River Park charity Trustee and founder of the Clean Up the River Brent campaign (CURB), Ben Morris, said the issue risks destroying the food chain in the waterways and could result in “dead rivers”.
He said: "This is a catastrophic failure of regulation. It is now possible to build, market and sell properties that flush sewage straight into our rivers, and no-one spots it until it is too late. The regulatory system has broken down, and nobody wants to bear the costs of looking after our environment. Sewage pollution kills wildlife and turns healthy rivers into disgusting drains."
A spokesperson for Thames Water told the Local Democracy Reporting Service (LDRS) that water companies don't have the powers to force private properties to fix their misconnections but work with property owners and local authorities so they can be fixed voluntarily. Failing that, it would need support from local authorities to legally enforce cases that have not been resolved.
The spokesperson said: "Households and buildings which are connected to the wrong drainage pipe can have a serious impact on the environment. Most misconnections will have been done entirely by accident but [it] is the responsibility of the property owner, which is why we would urge freeholders or developers fitting new connections to make sure they're plumbed in properly."
They added: "We have identified seven buildings in the Brent and Crane area which are misconnected, and have made those responsible aware to ensure all wastewater is taken to our sewage works where it can be safely treated. We have a programme of work to help identify and investigate misconnections and we also fund local projects across our region, which have been a great way to increase awareness of the issue, while involving communities to take stewardship and help manage their local environments."
When asked whether they were getting the necessary support from councils, the company did not respond. The Brent River Park Charity and the Friends of the River Crane are now calling on Barnet, Harrow and Ealing Councils, the Environment Agency, Thames Water, the Greater London Authority and the developers to work together to resolve the problems at these and other similar developments.
In the longer term, they claim this requires tougher legislation to ensure that all water connections are properly inspected and that those developers who connect foul water pipes to rivers are punished.
Harrow and Ealing councils did not respond to the LDRS requests for comment, but Barnet Council called the situation “unacceptable” and said it is concerned about the impact the growing number of these types of incidents are having on residents, biodiversity, and the local environment. However, the local authority also criticised the “fragmented legislation” which allows it to happen.
A spokesperson for Barnet Council told the LDRS: "New property developments are required to submit detailed plans for the proper management of sewage to prevent such pollution. However, many adaptations and conversions of existing properties take place without proper consideration and can result in these misconnections. We are doing all that we can to raise awareness about this issue, including issuing advice to residents setting out how they can help by checking the water flow connections in their homes."
They added: "The Water Industry Act provides Thames Water with powers to carry out works on any land/property to prevent and stop pollution from occurring to the local watercourses. This includes undertaking enforcement action on misconnections from private properties. However, this is a complex area with fragmented legislation which is not helping, and as such we continue to work collaboratively with the Environment Agency and Thames Water in line with the legislation."
The seven misconnections revealed in the EIR have still not been fixed, so, in the meantime, raw sewage continues to pour out of these properties and into the urban rivers.
Mr Morris said this pollution has enormous long-term consequences for the local environment, with a reduction of invertebrates in rivers meaning limited food sources for the fish and, ultimately, being left with “a river that is a sewer”.
A spokesperson for the Environment Agency said: "Misconnections are a major cause of pollution, especially in urban areas, where the high density of households and associated drainage increases the likelihood of misconnections and therefore the impact on nearby watercourses."
They added: "We encourage anyone who is installing a new toilet, sink, washing machine or dishwasher, to make sure their plumber is connecting them to the wastewater sewer rather than surface water drains. Your water company will be able to provide advice on making sure everything is connected correctly.”
