Health & Saf. Code, § 6660

At any time after the annexation of territory, the board may issue bonds to raise money for any of the purposes stated in Section 6512 hereof in or for the benefit of said annexed area in the same manner as in any other part of the district, except, only qualified electors resident within the annexed territory are entitled to petition or vote in the proceedings. In the event any such bonds are issued in such annexed territory, or in lieu thereof proceedings are had under Article 3 of Chapter 4 of this part, said territory shall not be subject to taxation for any bonds of the district or of any area previously annexed thereto theretofore authorized to be issued for one or more of the same purposes under Article 1 of Chapter 6 of this part. When no such bond proceedings are intended to be taken in such territory, then in the order of the sanitary board fixing the boundaries thereof, or by resolution adopted subsequently thereto when it is found by said sanitary board to be necessary in order to provide equality of taxation in said annexed area, said sanitary board may determine that said annexed area shall not be subject to taxation for any prior indebtedness of said district or of any other part thereof. Certified copies of said resolution shall be filed with the county clerk and also with the county assessor and with the State Board of Equalization in Sacramento and thereafter said annexed area shall not be subject to taxation for any such prior indebtedness.