Obviously not just water but, after running a bunch of carrots through the juicer along with a little bit of lemon and a handful of sage, there was quite a lot of resultant pulp which was damp but not dripping. I probably would have got some more juice just by running it through again but I decided to experiment by wetting the pulp with some sparkling water before adding it back to the hopper.
The result seemed to work well and I suspect that it helped liberate a bit more of the goodness out of the pulp without making the resultant juice seem dilute.
It was a good combination, by the way, both as it was and with the addition of a couple of peeled oranges (yes, I learned my lesson about unpeeled oranges).