Buildings with 10+ residential units must be fully registered with the local rent boards. That means each unit's unique “stats” must be on file (and updated annually) in a central data base hosted by the Rent Board. The data must include the names and contact information of individual tenants.
The Tenant Protection Act caps rent increases for most residential tenants in California. Landlords can't raise rent more than 10% total or 5% + CPI increase (whichever is lower) over a 12-month period. No-fault evictions are prohibited, so landlords can't evict a tenant without cause.
A business license is required when a person is conducting, managing or carrying on the business of operating an apartment house or properties containing five (5) or more rental units. (A.M.C. 3.28.