Streets and Highways Code § 5563
CHAPTER 20. Reassessments to Relieve Owners
No action shall be brought to contest, modify, annul, review or in any way attack the validity of the reassessment and the proceedings had under this chapter unless the same shall have been commenced within 30 days after the recording of the diagram and reassessment, and thereafter all persons shall be barred from any such action or any defense of invalidity of the reassessment and all bonds issued thereon.