California Code, Labor Code - LAB § 6203

If a rehabilitation plan requires an injured employee to attend an educational or medical facility away from his home, the injured employee shall be paid a reasonable and necessary subsistence allowance in addition to temporary disability indemnity. The subsistence allowance shall be regarded neither as indemnity nor as replacement for lost earnings, but rather as an amount reasonable and necessary to sustain the employee. The determination of need in a particular case shall be established as part of the rehabilitation plan.