The dewatering holes are typically used to lower groundwater levels before the start of open cut or underground coal mining operations.
Adani has sunk six dewatering bores, Coast and Country spokesman Derec Davies told the ABC.
"They've needed approval, a groundwater approval, for these bore," he reportedly said.
"They don't have that.
"They've drilled into Great Artesian Basin aquifers, they've put at risk our groundwater particularly at a time when half the country's in drought."
The Queensland government environment department has confirmed that it has launched an investigation into the matter.
Adani told the ABC it was abiding by the conditions of the Carmichael project's approvals.
"Drilling has been undertaken at the Carmichael mine site to take geological samples and monitor underground water levels," an Adani spokeswoman said.
"This is project stage one activity as permitted under Environmental Authority for the mine, which was issued in April 2016."
The company had "not been notified of an investigation."
