Cal. RTC § 75.15

(a) For fixtures, other than fixtures that are included in a change in ownership or that are included in a structure and are assessed at the completion of the new construction of a structure pursuant to Section 75.12, taxpayers shall report to the assessor once each year at the time the annual property statement is due, on the fixtures added to real property and fixtures removed from real property, the dates of those additions and removals, and the cost of each in the applicable period as follows:

(1) In 1997, the prior 10-month period from March 1 to January 1.

(2) In 1998 and each year thereafter, the prior 12-month period from January 1 to January 1.

This reporting requirement shall not apply to fixtures added or removed on or after the first day of the month following the effective date of the act adding this sentence to this subdivision. One supplemental tax bill shall be prepared for those fixtures based on the cost of the fixtures added and subtracted from real property, the date of each addition or subtraction, and the appropriate tax rate computed pursuant to Section 75.41.

The taxes due from the resulting tax bill shall be collected in the same manner and at the same times as other supplemental tax bills mailed on the same date.

(b) For the purposes of the supplemental roll, taxpayers shall report pursuant to this section only those fixtures which are taxable on the supplemental roll.

(c) This section shall become operative on March 1, 1987.