Drinking water alert for Lower Clarence

A DRINKING water alert has been issued for the Lower Clarence.

Clarence Valley Council (CVC) issued the warning after test results revealed unacceptable levels of Escherichia coli (E coli) in the water supply.

Frank Vaarwerk, an operations engineer with CVC, said although council could not be 100 per cent certain, the problem was most likely caused when pump rates were increased to lift chlorine levels in the Maclean reservoir.

"We increased the pump rates for about half-a-day in an attempt to increase chlorine residuals in the Lower Clarence," he said.

"In doing so, it looks like we might have stirred up some sediment."

Mr Vaarwerk said CVC had already begun rectification work.

He said his department was manually increasing the chlorine dose at the Maclean reservoir and carrying out 'flushing'.

Meanwhile, Mr Vaarwerk strongly recommended Lower Clarence residents boil all water intended for human consumption.

He said the water needed to be brought to the boil and kept there for at least one minute, before allowing it to cool. The water should then be placed in a sealed container and placed in the fridge.

"It's a precautionary measure," he said.

"At this stage there is no evidence of an outbreak of illness that we can contribute to the water supply.

"We're doing this in conjunction with NSW Health who are also monitoring the situation and concurring with our actions."

Mr Vaarwerk said tests done since the initial discovery had revealed the levels of bacteria had reduced, but were still above acceptable levels. He said two consecutive 'clear' test results were required before the water alert could be lifted.