  We study the effect of volumetric constraints on the structure and electronic
transport properties of distilled water in a nanopore with embedded electrodes.
Combining classical molecular dynamics simulations with quantum scattering
theory, we show that the structural motifs water assumes inside the pore can be
probed directly by tunneling. In particular, we show that the current does not
follow a simple exponential curve at a critical pore diameter of about 8 {\AA},
rather it is larger than the one expected from simple tunneling through a
barrier. This is due to a structural transition from bulk-like to "nanodroplet"
water domains. Our results can be tested with present experimental capabilities
to develop our understanding of water as a complex medium at nanometer length
scales.
