Northumbrian Water has been fined £240,000 after a damaged manhole led to sewage leaking into a watercourse in County Durham.
At Newcastle Crown Court, the water company pleaded guilty to two charges of causing the discharge of sewage into a stream on March 13 and 14 in 2017.
The court heard that a brick appeared to have blocked a combined sewer causing raw sewage to pour out of manhole chambers and flow into Coundon Burn at Auckland Park, Bishop Auckland.
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A member of the public reported the initial incident to Northumbrian Water, who sent out an emergency crew to clear the blockage.
But when officers returned to clear up the following day, they found a second manhole further downstream leaking sewage into the burn. They cut into the pipe and discovered a brick surrounded by rags and effluent.
An Environment Agency officer subsequently discovered a plume of discoloured water going into the River Gaunless from Coundon Burn.
Sample results indicated raw sewage, potentially fatal to aquatic life, had entered the stream.
The court was told the "bed of the burn was almost entirely covered in thick sewage fungus for at least 300m".
Northumbrian Water said the brick blockage was from a damaged manhole chamber on farmland.
The company admitted the two offences on the basis the discharge arose due to third party damage to the manhole during farming activities.
Passing sentence, Judge Robert Adams said the company had been negligent and said steps could have been taken to prevent such incidents.
He added that the North East had a lot of agricultural land where heavy machinery was used and damage to manholes near farmland was "wholly foreseeable", for which preventative measures could have been put in place.
He further added: "It's foreseeable that damage would be caused if steps were not taken to prevent that damage occurring."
He said there should have been a system to identify vulnerable manholes near farmland and a way of notifying landowners about them as well as marker posts being put in place alerting farmers to their locations.
"Such preventative measures would be achievable and well within the means of the company," said Judge Adams.
"I'm satisfied there was a failure by the organisation as a whole to provide reasonable care and put a system in place to avoid the offences."
The court heard that Northumbrian Water had since taken steps to remedy the problems. The firm was in the process of identifying vulnerable manholes to prevent leakage into inland waters and marker posts had also been put in place. In addition, a monitoring system had been developed.
Northumbrian Water's barrister, Mark Balysz, said the company had made major efforts over the years to improve its performance to make it a forerunner in the industry.
He added: "This is a company that has made strenuous efforts over the years and those efforts have paid dividends."
The company was fined £240,000 and ordered to pay costs of more than £34,200.
After the hearing, Rachael Caldwell, environment manager for the Environment Agency in the North East, said: “We take our responsibility to protect the environment very seriously.
"Water companies are aware that their activities have the potential to cause serious environmental impacts and they have a legal duty to avoid pollution. The regulations are clear.
“Our officers worked tirelessly to bring this case to court and we’re committed to holding water companies to account.
“The Environment Agency has secured fines of over £137m since 2015 with record fines handed down last year, making it clear that polluters will pay for damage to the environment.”
