Question

what is present whenever there is a buildup of charge

Answer 1

Horribly worded question. Well, either the presence of or lack of electrons. That's all charge is. If there is a negative charge there are extra electrons, and if there is a positive charge, there is a lack of electrons.

Other answers could include: electric field, a difference in electric potential, a voltage, a magnetic field if the charge is moving, electrostatic force, electrical potential energy.

Answer 2

Well, I agree some context is necessary.
If the context is 'conservation of charge', then the expected answer is pretty clear.

Answer 3

@spidermoney : have you found out what the answer is?