As I was reviewing the data and papers gathered together for the optical properties of water, I discovered that the people who have reported the optical absorption of water fall into two groups: those who actually do measurements and those who compile all the currently available data and choose a reasonable set. In general, the former group are compelled to do their measurements because they are disappointed by the current status of compiled data. The discussion section of these papers always makes it clear that their data is in agreement with published work and yet slightly better. Of course, the group that compiles existing data are then compelled to create yet another compilation so that there will be a nice accepted water spectrum.
All the data on this page is presented in terms of wavelength in nanometers and the Beer's law absorption coefficient µa that is presented in units of inverse centimeters.
If you are still not clear on where to look for the optical properties of water then you should probably click here.