75 ILCS 5/4-13
A Board of Library Trustees may, by resolution, create and maintain a working cash fund, for the sole purpose of enabling the library board to have in its funds, at all times, sufficient money to meet demands thereon for ordinary and necessary and committed expenditures for library purposes.
Such working cash fund shall be known as the local library working cash fund and may contain any amount deemed necessary by the Board to satisfy the purpose of the fund; provided, that the balance in the fund shall not at any time be allowed to exceed .2% of the full, fair cash value of all taxable property within the corporate limits, as equalized or assessed by the Department of Revenue as of the year the fund is established or, if such fund is established after January 1, 1979, then for the year 1978. The money for such fund shall only accrue from the local library working cash fund tax authorized to be levied pursuant to Section 3-9. The Board may appropriate moneys to the Working cash fund up to the maximum amount allowable in the fund, and the working cash fund may receive such appropriations and any other contributions.
Once the fund has been created, the proceeds shall be deposited in a special and separate fund, and may be carried over, from year to year without in any manner reducing or abating a future annual library tax levy. It shall be identified in the appropriation each year, but shall not be deemed as a current asset available for library purposes.
The proceeds of such fund may be transferred from the local library working cash fund to the general library fund, and disbursed therefrom in anticipation of the collection of taxes lawfully levied for general library purposes or in anticipation of such taxes, as by law now or hereafter enacted or amended, imposed by the General Assembly of the State of Illinois to replace revenue lost by units of local government and school districts as a result of the abolition of ad valorem personal property taxes, pursuant to Article IX, Section 5(c) of the Constitution of the State of Illinois. Such taxes when collected, and after payment of tax warrants, shall be drawn upon to reimburse the working cash fund.
75 ILCS 5/4-13