Idaho Code § 33-2609
The board shall prepare and adopt an annual budget, stating anticipated revenues and expenditures, indicating what support and maintenance of the library will be required for review and approval by the city council for the ensuing year.
All funds for the library shall be in the custody of the city treasurer unless otherwise provided by city ordinance, and shall be used only for library purposes. The board shall have control of library expenditures. Money shall be paid for library purposes, only upon properly authenticated vouchers of the board of trustees. The board shall not make expenditures or incur indebtedness in any year in excess of the amount of money appropriated for library purposes. The board may hold a separate checking account to be used to pay petty expenses of the library. This account shall be audited along with other library funds.
Idaho Code § 33-2609