California Apartment Association. With more than 17,000 members who provide approximately 800,000 homes to California families, the California Apartment Association (CAA) is the nation’s largest statewide trade association for people who own or manage rental property. CAA is dedicated to protecting its members’ investments through political and legal advocacy, assisting them to comply with new laws and regulations, and effectively communicating information on emerging industry trends, risk management and best business practices.