Cal. Sts. & Hy. Code § 8801
If any lot or parcel of land becomes tax-defaulted property for nonpayment of taxes and of any installment of the assessment thereon, or of the penalties, interest, or costs on the same, or for the nonpayment of any installment of the assessment or of the penalties, interest, or costs on the same, the declaration of default pursuant to Section 3436 of the Revenue and Taxation Code and the deed issued pursuant to Section 3708 of that code, are primary evidence of the regularity of all proceedings had prior thereto, and shall be conclusive evidence of all things of which bonds issued upon the security thereof are conclusive evidence, and prima facie evidence of the regularity of all proceedings subsequent to the issuance of the bonds, and the deed conveys to the grantee the absolute title to the lands described therein, free of all incumbrances, except the lien for other state, county, and city taxes, unpaid installments, interest, and penalties under the same proceeding, and unpaid installments, interest, and penalties, the lien of which is subordinate thereto, and except all public improvement assessments which may have priority thereover.
Ca. Sts. and High. Code § 8801