The taxable property within the excluded area shall remain subject to any taxes theretofore levied by the municipal water district and shall continue to be taxable by the municipal water district for the purpose of paying the bonded or other indebtedness of the municipal water district, if any, outstanding or contracted for at the time of such exclusion and until such bonded or other indebtedness is satisfied, to the same extent that such property would be taxable for such purpose if the exclusion had not occurred.