The Waitangi Tribunal has been unable to establish whether Maori have any rights to aquifers.
The tribunal says it lacks evidence and legal argument to make a finding.
A claim over aquifers was made by the Maori Council and 10 tribes, and was part of an urgent hearing that also considered rights to springs, streams, lakes, rivers, and geothermal resources.
In an interim report issued on Friday, the tribunal found Maori still have ownership rights to bodies of water, or in legal terms, residual proprietary rights.
But it hesitated to define the exact nature and extent of Maori rights in aquifers when the Treaty of Waitangi was signed.
It says it cannot be the case that all aquifers were known and enjoyed by tribes in 1840.
But the tribunal noted one claimant argued that if Maori did not know that aquifers existed in 1840, and lacked scientific knowledge to use them, Maori would be protected by the Treaty right of development.
However, the report says without any specific submissions, the tribunal lacked the evidence and legal argument to make a finding about the nature and extent of Maori rights in aquifers.