Cal. SHC § 6610

As a separate, distinct and cumulative remedy, the holder of any bond upon which any payment either upon the principal or of the interest has become delinquent may, if the city which initiated the proceedings is not a county, at any time after three months after the date it is provided by ordinance or charter of the city that taxes are due, or if a county initiated the proceedings or collects the taxes for the city at any time after four months next succeeding the fourth Monday of September, following the date of delinquency of principal or interest and prior to the expiration of four years after the due date of the last installment upon any bond or of the last principal coupon attached thereto, file and maintain an action to foreclose the lien of the bond and recover the amount due thereon.

No action shall be commenced pursuant to this section until the expiration of 15 days after a notice containing the amount of the payment due, the date the payment is or was due, penalties which may accrue for failure to pay, and notice of the foreclosure action which may occur if payment is not made is mailed, postage prepaid and registered, by the bondholder, or his representative, to the owner of the property at his last known address as it appears on the tax rolls.