California Code, Streets and Highways Code - SHC § 8881

Where a special reserve fund is created for a bond issue, the assessment levied on any parcel for the payment of the bond issue shall be reduced upon the payment, in whole or in part, of the assessment pursuant to provisions for either (1) cash payments of assessments prior to the issuance of the bonds or (2) advance payment of assessments following the issuance of the bonds.

The proportional reduction on the assessment shall equal the ratio of the total amount initially provided for the special reserve fund to the total amount originally assessed in the proceedings for the bond issue.