A Thames Water spokesman says the water is not sewage.
They say it is the result of a burst water main, which had mixed with silt and mud.
Engineers are on site working to manage the problem.
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The rumbling row between black cab drivers and private hire car firms could be resolved this week.
The twins cubs, which were born in June, have been named Bert and Ernie after characters from Sesame Street.
The two victims died from their injuries in hospital after the explosion in Hertfordshire.