The firm pleaded guilty to discharging raw sewage at a water pumping station in Belle Vue which then made its way into local ponds, causing the deaths of hundreds of fish.
Yorkshire Water was also ordered to pay Environment Agency costs of £24,760 as well as a victim surcharge of £120 after the hearing at Sheffield Crown Court.
The court heard that the incident took place in April 2014 where raw sewage was discharged from the defendant company’s pumping station at Sandy Lane, Belle Vue into a water course and ultimately into two local ponds.
The discharge of sewage resulted in a raised level of ammonia in the water of the ponds and a reduced level of dissolved oxygen for a considerable period of time.
The pollution from the illegal discharge was traced for over 3.5km downstream from the pumping station and a large number of fish died due to the toxic effects of ammonia.
Richard Moore, Team Leader at the Environment Agency said: “Safeguarding the environment is an essential part of how all water companies must operate. The sentencing in this case shows we will continue to take companies to task where they fail to meet environmental standards.”