Cal. Pub. Resources Code § 8810
The plane coordinates of a point on the earth's surface, to be used in expressing the position or location of the point in the appropriate zone of CCS27 or CCS83, shall consist of two distances, expressed in feet and decimals of a foot or meters and decimals of a meter. One of these distances, to be known as the "East x-coordinate," shall give the distance east of the Y axis; the other, to be known as the "North y-coordinate," shall give the distance north of the X axis. The Y axis of any zone shall be parallel with the central meridian of that zone. The X axis of any zone shall be at right angles to the central meridian of that zone. When the values are expressed in feet, the "U.S. Survey foot," (one foot equals 1200/3937 meters) shall be used as the standard foot for CCS27 and CCS83. For CCS2022, the official conversion, commonly called the international foot, shall be used (one foot equals 0.3048 meters).
Ca. Pub. Res. Code § 8810