[dragonwriter]

No, there should be an equilibrium market price in dollars thst they both pay if they are participants in a shared market. That doesn't mean the value to each is the same.

Of course, the fact that they have access to that shared market also changes the value to each of them from that in the original hypothetical.

[barongrounds]

I think we have a difference in vocabulary. I would say value and equilibrium market price refer to the same thing, but you are saying it is the particular use it has to the individual which is of course not quantifiable. Assuming the person who's had no water has access to a functioning market they will only pay market price. Arguing about them perceiving it to have a higher value seems like a pointless philosophical argument.