Water Oligomers in Crystal Hydrates—What's News and What Isn't?

How does one find out whether an interesting water aggregate observed in an organic crystal structure is novel? The first place to look is in the Cambridge Structural Database (CSD). The data are there, but analysis is difficult and it is not routinely done. The result? Many of the water chains, rings, sheets, and clusters reported as novel in the recent literature are actually redundant with published structures in the CSD.