Heavy rain led to sewage being dumped into the River Wensum in the heart of the city.
Folk walking over the Lady Julian Bridge at Riverside noticed the dirty water spilling into the river during downpours earlier this week.
The waste was emptied as part of Norwich’s overflow system, which is designed to release excess storm water to prevent sewer flooding.
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READ MORE:A passer-by caught in the rain noticed the sewage, saying: "Moments after the rain started the drainage gate opened and started dumping into the River Wensum.
"Water companies around the UK have received wide condemnation for the increased dumping of sewer outlets.
"Now it seems Norwich is included when it comes to a list of places hit by this increased dumping trend."
Combined Sewer Overflows (CSOs) are used in areas across the country, but in August 2022 the government implemented a reduction plan to reduce the use of the system due to its harm to public health and the environment.
An Anglian Water spokeswoman said: "CSOs were originally designed to protect homes and businesses from flooding during heavy rainfall, like we saw in Norwich recently.
"There was a short CSO release on the River Wensum when the system was processing a huge volume of water during the heavy rain.
"This was within the levels permitted by the Environment Agency.
"Our teams have investigated this today and found no visible impact on the river, and we can confirm that the CSO is not operating today."
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READ MORE:But the water company say it planning to reinvest "more than £200m" to tackle to ongoing issue of CSOs.
Anglian Water added: “We recognise that CSOs are no longer the right solution and our eventual ambition is to remove CSOs like the one in Norwich.
"We're reinvesting more than £200m to reduce storm spills across the East of England.
"As part of our 'Get River Positive' commitment we’ve promised that storm overflows will not be the reason for unhealthy watercourses in our region by 2030."
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