640.110.  Fund established — deposits, disbursements — unexpended balance not transferred. — There is hereby established in the state treasury the "Safe Drinking Water Fund".  All fees or other moneys payable under the provisions of section 192.320 and sections 640.100 to 640.140 shall be payable to and collected by the director of the department of revenue and deposited in the safe drinking water fund.  The money in the safe drinking water fund, after appropriation, shall be expended upon proper warrants issued by the commissioner of administration for the payment of salaries and expenses, including any fee or payment necessary for carrying out the provisions of section 192.320 and sections 640.100 to 640.140.  Any portion of the fund not immediately needed for the purposes authorized shall be invested by the state treasurer as provided by the Constitution and laws of this state.  All income from such investments shall be deposited in the safe drinking water fund.  Any unexpended balance in the safe drinking water fund at the end of any appropriation period shall not be transferred to the general revenue fund and, accordingly, shall be exempt from the provisions of section 33.080 relating to the transfer of funds to the general revenue funds of the state by the state treasurer.