The text is old scripture, at one point it talks of a person who is pulling water from a well. It doesn't necessarily have to be their job. How do you refer to the person who is pulling water out of a well right now?
It seems that the best word that was suggested in comments (now deleted) is "the man who is drawing water" or "water drawer".
The biblical citation (Joshua 9:21) is:
This sounds a little archaic, but would seem to suit the context, and there is no modern equivalent in Western culture. The biblical meaning is more general, indicating a menial labourer.