Model Rockets are included in the Health and Safety Codes (HSC), sections 12500 through 13000.
http://www.nar.org/wp-content/uploads/2014/05/California-Health-Safety-Code-Rockets.pdf
http://www.nar.org/wp-content/uploads/2014/05/California-Modroc-Regs.pdf
To obtain a copy of the State of California Model Rocketry Regulations, write to:
California Dept of Forestry and Fire Protection
Office of State Fire Marshal
Prefire Engineering
P.O. Box 944246
Sacramento, CA 94244-2460