Mr. Mike
Have this printed out for your inspector next time he ask's you for 2 ground rods.
2008 NEC—250.56
Resistance of Rod, Pipe, and Plate Electrodes.
A single electrode consisting of a rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional electrode of any of the types specified by 250.52(A)(4) through (A)(8). Where multiple rod, pipe, or plate electrodes are installed to meet the requirements of this section, they shall not be less than 1.8 m (6 ft.) apart.
The requirement for a single electrode that does not have a resistance of 25 ohms or less to be augmented does not apply to any electrodes other than rod, pipe or plate. It is required to augment such an electrode with one additional electrode of any of the types specified by 250.52(A)(4) through 250.52(A)(8) so 250.52(A)(1) for underground metal water pipes, 250.52(A)(2) for metal frame of a building or structure, and 250.52(A)(3) for concrete-encased electrodes were deleted from the list of permissible electrodes to be used for augmenting the rod, pipe or plate electrodes.
Just like a criminal case. It's up to them to prove it's not 25 ohms or less. Not your problem. Although, you'll be getting turned down for screws on covers missing and things like that for the next 2 yrs.