London rivers being pumped full of raw sewage after ‘errors’ on new-build flats

Hundreds of homes in London are flushing their toilets directly into rivers, and in some cases have been doing so for years.

The problem is well known by councils and Thames Water, and has been described as ‘a catastrophic failure of regulation’.

An Environmental Information Request specified at least 84 homes in west London alone which are wrongly plumbed,but the problem is thought to be much wider, potentially reaching even 1% or more of London’s housing stock which would be tens of thousands of residences.

One apartment block of 14 flats was identified as having a ‘misconnection’ in its plumbing over six years ago in April 2018, while the freeholder of another building was notified in 2021. 

But with the properties still not replumbed, poo and wee continue to flush into the River Brent and River Crane, tributaries of the Thames.

On a visit to the Brent River Park last week, Metro saw two sections of the River Brent where sewage was pouring into the water.

The smell itself made the problem clear, but we also witnessed sanitary towels and wet wipes stuck at the entrance to what was supposed to be a surface water drain.

This issue is separate to sewage discharging into rivers through storm overflows, which is controversial but permitted when heavy rain could otherwise overwhelm the sewage system. 

Quizzing mayor Sadiq Khan in May, Hina Bokhari AM stated there were ‘currently 943 identified misconnections in London’, saying he would have his work cut out to make the capital’s rivers swimmable within ten years.

Misconnections can range from a single dishwasher to an entire newbuild block of flats connected wrongly.

On the day we visited the Brent, water was freely flowing from a surface water outflow although it had not rained recently, and murky ‘sewage fungus’ was growing.

Ben Morris, founder of the Clean Up the River Brent campaign and a Brent River Park charity trustee, took measurements of both ammonia and phosphate levels from water pouring into the river. 

His colorimeter maxed out at 9.99 mg/L for ammonia before we arrived that day, meaning the true figure was higher, and by the time we visited mid morning it was still at 9.86 mg/L. Raw sewage would see a typical level of 20 to 40 mg/L.

Ben said levels over the course of the working day showed a graph ironically similar to the shape of someone’s backside, with levels highest in the morning and evening when people were home from work. 

This could be the biggest source of chronic pollution for London’s rivers, harming fish and invertebrates, turning ‘healthy rivers into disgusting drains’, and taking us back to the time of the ‘Great Stink’ in 1858 before we had treatment works, he said.

Why do these plumbing misconnections happen across London?

The problem happens when a waste pipe is accidentally plumbed into a surface water drainage pipe, rather than the correct pipe taking foul water to a treatment works. 

When this happens underground, it may not be immediately obvious, meaning that when it is discovered it may be difficult to rectify.

In many cases, it happens during conversion works to existing plumbing systems, such as when a building is converted to flats.

But it can also be a blunder during initial construction, as happened with the newbuild blocks in west London.

Who is responsible for enforcing rules on sewage?

It is the responsibility of the freeholder or property developer to ensure plumbing works are compliant with regulations.

Once they are notified of a misconnection by Thames Water, they have an obligation to fix it.

But if they don’t, it can be hard to work out exactly who should take action, whether that be councils, the water company, the Environment Agency, or someone else.

‘The whole situation is beautifully constructed for buck passing,’ Ben said, with rivers crossing borough boundaries and several different organisations tasked with managing sewage and river quality. ‘There aren’t clear lines of accountability.’

At least one of the owners/developers in west London are allegedly seeking to pass the costs of resolving it onto the leaseholders, with occupants ‘faced with enormous financial responsibilities that are not their fault’, the Friends of the River Crane Environment, the charity which made the information request, said.

Trustee Rob Gray said: ‘These seven blocks are only the ones that have been revealed so far in one small part of North West London; the true scale of this problem across the capital is therefore likely to be far greater.’

Ben Morris said: ‘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.

‘That is raw sewage going straight into a river in a country that is supposedly advanced, cares about the environment, cares about hygiene, and has a building regulations system in place. How can that not be a scandal?’

A Thames Water spokesperson said: ‘Most misconnections will have been done entirely by accident but 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.

‘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.’

Has your home been affected by this? Contact [email protected].

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