California Code, Revenue and Taxation Code - RTC § 4186

(a) Special assessments pledged to the payment of debt service on bonds issued pursuant to the Improvement Bond Act of 1915 (Division 10 (commencing with Section 8500) of the Streets and Highways Code) for which the local agency has covenanted to foreclose on behalf of the bondholder pursuant to Section 8830 of the Streets and Highways Code.

(b) Special taxes pledged to the payment of debt service on bonds issued pursuant to the Mello-Roos Community Facilities Act of 1982 (Chapter 2.5 (commencing with Section 53311) of Part 1 of Division 2 of Title 5 of the Government Code) for which the local agency has covenanted to foreclose on behalf of the bondholder pursuant to subdivision (b) of Section 53356.1 of the Government Code.