So, If I wanted to limit myself to just minor plumbing repairs such as installing sinks, drain cleaning, faucets, and toilet repairs, I would be OK with a local business license and life saver certification (background check)?

" All businesses or individuals who construct or alter any building, highway, road, parking facility, railroad, excavation, or other structure in California must be licensed by the California Contractors State License Board (CSLB) if the total cost (labor and materials) of one or more contracts on the project is $500 or more. Contractors including subcontractors, specialty contractors, and persons engaged in the business of home improvement must be licensed before submitting bids. Licenses may be issued to individuals, partnerships, corporations, or joint ventures..."

Go to Contractors State License Board to further educate yourself on the issue.

Hope that helps

Milo