The effluent has been flowing from a Sh4.5 billion World Bank-funded treatment plant at Gatong’ora in the area.
Raphael Burugu said he lost all the fish worth Sh700,000 in his three ponds.
Fish farmers in Juja are counting huge losses following the death of thousands of their stock following a discharge of sewage effluent into River Ruiru.
The effluent has been flowing from a Sh4.5 billion World Bank-funded treatment plant at Gatong’ora in the area.
The farmers accused Ruiru-Juja Water and Sewage Company (RUJWASCO), which runs the waste treatment plant, of ignoring their plight.
“Over the last two weeks untreated sewage has been flowing into the river daily. We fear that soon there might be an outbreak of diseases,” said Ms Carol Wanjiru.
The community water project chairman Wilson Kabata said samples taken from the river and tested by the government chemist showed that the water is unfit for use.
Area chief Sarah Waigwe said the RUJWASCO has refused to heed pleas by the county government and residents urging them to stop discharging the waste.