Cal. Gov. Code § 6802

The years 1900, 2100, 2200, 2300, or any other future hundredth year, of which the year 2000 is the first, except only every fourth hundredth year, are not leap years, but common years of 365 days. The years 2000, 2400, 2800, and every other fourth hundredth year after 2000 and every fourth year, except as provided in this section, which, by usage in this State is considered a leap year, is a leap year consisting of 366 days.