Wessex Water has been fined £5,000 for polluting a Somerset river with sewage.
The Environment Agency says the incident was avoidable
The company pleaded guilty to causing poisonous, noxious or polluting matter to enter the Washford River and was also ordered to pay £1,000 costs by Minehead Magistrates.
The Environment Agency claims it discovered sewage flowing from an outfall pipe at Bye Farm on the river between Lower Washford and Kentsford during a visit in September 2002.
Wessex Water said the problem was caused by a blockage, of which there are two billion a year in the UK.
We do conduct routine inspections, but not 24 hours around the clock
Andrew King of the Environment Agency said "This was a serious incident that was avoidable.
"If telemetry equipment - which allows the automatic transmission of data by remote sources - had been fitted, Wessex Water would have been aware of the problem a lot sooner and could have responded more quickly.
"Such action would have considerably reduced any harmful effects on the river and surrounding environment."
John Delaney, divisional manager for Wessex Water, told News Online: "We do conduct routine inspections, but not 24 hours around the clock.
"Telemetry at the site was installed in March as part of our programme with the Environement Agency."
The sewage and associated debris - including toilet paper and sanitary towels - had collected beneath the outfall pipe and covered the river bed immediately downstream.
The outfall pipe was located in a field used by livestock and the Environment Agency says it should only discharge as an emergency at times of exceptionally high flows - and not during dry weather.