Anglian Water is to pay £100,000 to the Rockingham Forest Trust to make amends for discharging crude sewage into Willow Brook in Corby.
The company has also agreed to undertake site improvement works, and will pay the Environment Agency’s costs as part of a civil sanction called an Enforcement Undertaking (EU).
The pollution occurred on June, 21, 2014, when crude sewage was released into the Willow Brook in Corby.
This sewage resulted in pollution along 6km of the brook, leading to numerous reports of discoloured water as well as the death of up to 500 fish.
Upon inspection Environment Agency officers found that this pollution originated from Corby Water Recycling Works, which is owned by Anglian Water Services.
Anglian Water had been aware of a serious problem at the Corby site since 3pm on June 21, but failed to notify the Environment Agency until officers came to the Water Recycling Centre in the evening.
Following the incident, Anglian Water agreed under the terms of an EU to make a financial contribution of £100,000 to Rockingham Forest Trust, a local environmental charity which manages areas including the water environment in the Nene Valley.
Anglian Water also made improvements to the site to prevent similar incidents recurring, and paid £14,834.10 in costs to the EA.
Yvonne Daly, environment manager with the Environment Agency, said: “We will always take forward prosecutions in the most serious cases.
“However, we felt the Enforcement Undertaking was the most appropriate sanction in this case.
“We felt it to be a more proportionate response that would benefit the environment – achieving more than if the company had been convicted and fined.”