The water level at the Palantone water-supply plant in Bondeno (Ferrara) now stands at 3.14m, a level of pre-alert.
Last year it entered the pre-alert stage dipping to 3.02m in June.
The CER is an artificial waterway providing crucial irrigation to crops in one of Italy's most important agricultural areas.
The nation is in the grips of a prolonged drought that is leading to water shortages in many parts of the country.
Low levels of rain and snowfall this winter have exacerbated an already difficult situation after the lack of rainfall and long series of heat waves endured last summer hit its water resources badly.
Mild winter temperatures have also brought forward the melting of snow on the mountains.
Scientists say that extreme weather events like heat waves, supercharged storms, flooding and droughts are becoming more frequent and more intense because of climate change caused by human greenhouse-gas emissions.
ANSA
