YORKSHIRE Water has been fined £2,000 for polluting the River Dearne with sewage.
The company pleaded guilty to allowing polluting matter to enter controlled waters from its Clayton West sewerage works.
It was also ordered to pay costs of £472 to the Environment Agency which brought the case.
Huddersfield magistrates heard yesterday that on April 13 an Environment Agency officer noticed the River Dearne between Huddersfield and Barnsley was grey-brown in colour.
The source of pollution was traced to Yorkshire Water's Clayton West treatment works.
A tank had over filled and the sewage flowed into a disused pipe and straight to the river.
A valve on the pipe had been opened allowing the sewage to go into the river instead of to the treatment works where it should have gone.
Staff claimed the valve had been tampered with by vandals.
There was no padlock or security device to secure the valve which was the only thing stopping the sewage from getting into the river.
The company claimed it had stopped the discharge within an hour and had spent £4,000 on clean-up work.
After the case environment officer Dave Preston said luckily no fish were killed but the river habitat would have been affected by the sewage."