Toilets at Southampton flat block pump into River Itchen

Residents at Royal Court in Upper Grosvenor Road have unintentionally flushed nearly 11 million litres of waste into surface water drains instead of Southern Water's sewer system.

This equates to more than four Olympic-sized swimming pools worth of sewage and does not include wastewater from showers, baths, dishwashers and washing machines. 

The entire block was misconnected when it was built in 1989, Southern Water told the Echo.

This means that instead of plumbing waste pipes into the utility company's sewer system, Royal Court's toilets, dishwashers and washing machines pour into surface water drains instead.

Royal Court unintentionally poured nearly 11 million litres of sewage from toilets alone. (Image: Newsquest) Surface water drains then connect directly to the River Itchen.

One resident at Royal Court, who did not want to be named, was stunned when the Echo revealed the shock. 

She said she had "never heard" of any sewage problems at the block.

"I don't know how it happened or why but I'd like to know," they said.

The resident said she wanted to hear how illegal sewage installations could "slip through the cracks".

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And the team at Southern Water tasked with finding so-called misconnections has "never seen" such a case before this one.

"I’ve never seen anything like this before," Southern Water illegal misconnections team member Ben Trinder said.

Ben Trinder and Gary Masters from the illegal misconnections team. (Image: Southern Water) "It can take a lot of work to track down one faulty connection but it’s important work as a single loo can produce 20,000 litres of sewage a year."

Ben and his colleague Gary Masters used specialist devices to measure the presence of e-coli bacteria in surface water drains, culverts and streams.

The illegal misconnections team test the water at the River Itchen for e-coli. (Image: Southern Water) When they detected high levels near the Itchen, they lifted a series of manholes and looked for signs of contamination.

The misconnections team saw sewage pouring as they traced the source upstream towards Royal Court. (Image: Southern Water) This can include the scent of detergent, the presence of raw sewage itself or visuals of toilet paper and wet wipes.

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Cages are placed down manholes to catch the latter, and with signs of contamination clear, the misconnections team followed upstream until they reached Royal Court.

Evidence of staining and sewage at a manhole near Royal Court. (Image: Southern Water) "We put our CCTV camera down the surface water pipe and couldn’t believe our eyes," Ben said.

"Rows of private sewage pipes were punched through the side and into the drainage pipe. This pipe then runs straight into the Itchen."

The misconnections team witnessed sewage pouring into the manhole outside Royal Court while on site. (Image: Southern Water) Since discovering the misconnection, Southern Water has been pumping out the pollution before it reaches the Itchen and has been taking it by tanker to be treated.

'This requires some proper civil engineering'

Typically the homeowner is liable to fix misconnections, which can cost between £200 and £400 for a builder to reconnect a toilet in one house properly.

But at Royal Court, Southern Water is footing the bill for works due to the "scale and importance" of the finding. 

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Darko Zlatarek, misconnections team leader, said: “Normally fixing a misconnection is a simple matter, but this requires some proper civil engineering. It’s clearly right we get in there and fix it as soon as we can.”

Managing agents for Royal Court, Denfords Property Management, said that it has been informed that Southern Water will be carrying out necessary works to the drains.

The firm said it had not yet been contacted by Southern Water.

Roy Sansom, who applied for planning permission, oversaw development and still owns Royal Court, did not respond to the Echo's requests for comment.