  Biological membranes are essential for the cell life and hydration water
provides the driving force for their assembly and stability. Here we study the
structural properties of water in a phospholipid membrane. We characterize
local structures inspecting the intermediate range order (IRO) adopting a
sensitive local order metric, recently proposed by Martelli et al., which
measures and grades the degree of overlap of local environments with structures
of perfect ice. Close to the membrane, water acquires high IRO and changes its
dynamical properties, e.g., slowing down its translational and rotational
degrees of freedom in a region that extends over $\simeq 1$ nm from the
membrane interface. Surprisingly, we show that at a distance as far as $\simeq
2.5$ nm from the interface, although the bulk-like dynamics is recovered,
water's IRO is still slightly higher than in bulk at the same thermodynamic
conditions. Therefore, the water-membrane interface has a structural effect at
ambient conditions that propagates further than the often-invoked $1$ nm-length
scale, a results that should be taken carefully into account when analyzing
experimental data of water confined by membranes and could help us
understanding the role of water in biological systems.
