Any publicly owned utility which commences to provide any water service for, on, or to any land within a municipal water district which is providing service to the land and which land at the commencement of such service is subject to the lien of a bonded or contract indebtedness with revenues pledged for their payment, shall reimburse the district from the water revenues derived from charges made for service to such land, the amount which would have been paid by the district from water revenues for such bond or contract payments.