The City Auditor shall prescribe and require, except as they may be by law prescribed and required, the use of plain and uniform systems of keeping books of accounts by all City officers who are charged with the receipt or disbursement of any of the funds of the City or who may be authorized to purchase materials and supplies or employ labor for it. He shall prescribe the form of vouchers or other evidences of the receipt of money from the City or for the establishment of demands against the City. He shall at all times have access to and may inspect and take copies of all books on which entries are made, or are required to be made, relating to the receipt or expenditure of money on account of the City, and to all vouchers, accounts, bills, warrants, drafts, contracts, or other papers relating thereto.

He shall have power to administer oaths for the purpose of ascertaining the facts relating to any charge or claim against the City, made or claimed by any person, partnership, association or corporation whatsoever. He shall inquire into and inform himself as to the legality of all claims paid out of the City Treasury, or for which warrants thereon have been drawn, as well as the reasonableness of the prices charged or claimed for material, supplies or labor, and the facts as to the delivery or rendition thereof to or for the use of the City.