Cal. Mil. & Vet. Code § 1224

If the cost of construction or alteration under the contract is ten thousand dollars ($10,000) or more, from time to time, as the work of construction or alteration progresses, a certified architect or a certified structural engineer, hired by the district, shall make reports showing, of his own personal knowledge, that the work during the period covered by the report has been performed and materials used and installed, in every particular, in accordance with the approved plans and specifications.