CA Rev & Tax Code Section 5062

If any public land is heretofore or hereafter assessed and the taxes are not paid, the board of supervisors shall order the auditor to cancel the assessment if:

(a)

Verified application is made by the owner of the land, and

(b)

The applicant files with the board of supervisors a certificate of the Register of the United States Lands Office, or of the State Lands Commission, showing that the assessee or his successor in interest never received a patent or otherwise acquired title to the land.