A hypothetical condition can be applied to a situation that does not currently exist. Most commonly it is used for pre construction. This is the opposite. They want the value as if it was raw land ready to be improved.
Sounds weird but if you think about it, it isn’t. Treat it like if they wanted the value of the raw land that is currently improved with a burnout, obsolete structure or any improvement that is obsolete. In that case, you would determine the value of the raw land as if vacant and subtract the cost of razing the structure.
Now in this case, unlike above, the land can be improved with or without the well so you really don’t need to condition to have it removed AND you can give them the value without a well (I.e., remove the adjustment). I would just disclose that there is a functioning well. Do NOT say that it doesn’t exist! Just say that the value does not include the well. That effectively solves the appraisal problem and is not misleading.