Ind. Code § 5-16-1-1.4

Sec. 1.4. For the purpose of securing bids or for the purpose of causing the work to be done in the desired manner, the state or commission created by law (excepting the Indiana department of transportation) shall prepare, and place on file in its office, plans and specifications of the building or improvements sought to be constructed, erected, altered, or repaired whenever the estimated cost of the work is greater than twenty-five thousand dollars ($25,000).