2022 California Standards for Accessible Design Guide (effective January 1, 2023)

11B-607.4.2.1 Back wall.

Two grab bars shall be installed on the back wall, one located in accordance with Section 11B-609.4 and the other located 8 inches (203 mm) minimum and 10 inches (254 mm) maximum above the rim of the bathtub. Each grab bar shall be 24 inches (610 mm) long minimum and shall be installed 24 inches (610 mm) maximum from the head end wall and 12 inches (305 mm) maximum from the control end wall.