Cal. Sts. & High. Code § 9350

In the event of nonpayment of any reassessment or installment thereof or of any interest thereon, together with any penalties and other charges accruing under the laws or ordinances of the city and not later than four years after the due date of the last installment of principal, as a cumulative remedy, such amounts when due and delinquent may by order of the legislative body be collected by an action brought in the superior court to foreclose the lien thereof.