YORKSHIRE Water has been fined £2,400 after raw sewage polluted a Brighouse beck.
The company admitted causing polluting matter to enter controlled water - Clifton Beck, at Bailiff Bridge - on October 9, 2003.
Calderdale magistrates also ordered the company to pay £711 costs to the Environment Agency which brought the case.
Agency officers inspected the beck after a public complaint and discovered a combined sewer overflow discharging raw sewage fungus debris and a strong smell of sewage.
Water samples revealed reduced oxygen levels, also indicating the water was polluted, the court heard.
On returning the next day, an officer noted the water in the beck was clear and colourless but the bed was heavily contaminated by a grey growth indicating the beck had been polluted for a number of days with an organic pollution. Two dead fish were also found.
Yorkshire Water told the court the sewer overflow had discharged because there was a partial blockage in the downstream sewer, caused by the collapse of the sewer.
The sewer had collapsed at a point where a Yorkshire Water engineer had previously seen on a CCTV survey what he thought was a side join, but it could have been a hole in the side of the sewer.
The company added there were also other outfalls along that stretch of the beck that could have caused the fish deaths.