No money shall be drawn from the treasury of the county, nor shall any obligation for the expenditure of money be incurred, except pursuant to appropriation resolutions. Funds appropriated for multiyear capital projects and outstanding grants, however, may be carried over from year to year without being reappropriated. Accounts shall be kept for each item of appropriation made by the board. Each such account shall show in detail the appropriations made thereto, the amount drawn thereon, the unpaid obligation charged against it, and the unencumbered balance in the appropriation account, properly chargeable, sufficient to meet the obligation entailed by contract, agreement, or order.
Va. Code § 15.2-520