Many cities in CA impose their own business taxes. Before doing business in CA at all, we recommend connecting with your CPA and asking about the city and local tax implications.
It is also recommended that you double check the county requirements for doing business. Many CA counties will require a business license, even if you also need a city business license.
As an example, if you are doing business in Los Angeles, you must obtain a Tax Registration Certificate (TRC) and pay the required business tax due. You are considered to be engaged in business in the City of Los Angeles when you physically perform work within the City of Los Angeles for seven (7) or more days per year. The minimum tax under Section 21.188 is $153.00 per year or any portion of the year.
Another example, every business with San Francisco gross receipts of more than $1,090,000 or San Francisco payroll expense of more than $300,000, is required to make three quarterly estimated tax payments and file an annual tax return. Residential Landlords that rent four or more units, with annual gross receipts less than $1,090,000 and payroll expense less than $300,000 are only required to file an annual tax return.