Cal. Sts. & Hy. Code § 6530.5
The treasurer, within 10 days of the issuance of the certificate of sale, shall mail a notice to the owner of the property sold pursuant to this chapter. The notice shall be sent by first-class mail to the owner of the property as shown on the last equalized assessment roll and to any person whose name appears as an owner on the records of the county assessor's office which the county assessor will use to prepare the next assessor's roll. The notice shall state the following in at least 14-point boldface type:
IMPORTANT NOTICE
Your property located at ____ has been sold by the city (or county) treasurer because you did not pay for ____ improvements made in your area. You still have at least 11 months to pay $ (amount) which you owe plus penalties, interests, and costs. YOU CAN STILL SAVE YOUR PROPERTY. Contact the foreclosure clerk at the treasurer's office to find out the exact amount due. The telephone number is ____. If you do not pay this debt, you will lose your property and all the money you have invested in it. Act now!
Ca. Sts. and High. Code § 6530.5