The permission shall provide that the charge made by the permittee for gas or water shall not be greater than the charge therefor made by the permittee for such service elsewhere, and shall provide that the permittee shall pay a reasonable charge, to be determined by the legislative body granting the permission, for the use of the work or improvement. Such rental shall be paid to the treasurer of the county or city at least semiannually and placed in a special fund, which shall be used for the improvement or replacement of the work or improvement or any part thereof.