New analysis shows water takes from the Heretaunga aquifer in Hawke's Bay have reached their limit, that prevents streams and rivers running dry in the summer.
The scientific advice has been given to a group of community stakeholders, called TANK, which is reviewing the way land and water resources are managed in the area.
The regional council's chair, Rex Graham, said water drawn from the aquifer affects the flows of rivers and streams in the area.
"It's not nudging, it's at its limits, this is the first time we've said we are at the limits of the extraction and the heaviest point of extraction which is in our summertime."
Mr Graham said in the long term, the region would need to consider an irrigation or water storage scheme for the area.