In January 2010, California (along with Vermont) adopted some of the highest restrictions on the amount of lead content in plumbing fixtures in the country.
According to AB 1953 (California’s Lead Plumbing Law): "No person shall introduce into commerce, for use in California, any pipe, pipe or plumbing fitting, or fixture intended to convey or dispense water for human consumption through drinking water or cooking that is not lead free. This includes kitchen faucets, bathroom faucets, and any other end-use devices intended to convey or dispense water for human consumption through drinking or cooking."
It is illegal to sell products that do not meet these requirements in both states.
If you didn't know that yet, you need to know, especially those of you who buy online, from out-of-state, or from a less-than-reputable plumbing store. Many plumbing manufacturers have adapted to these state laws -- some with a partial lineup of compliant fixtures, and others with full lines. It’s not good enough to say they are compliant as the fixtures need to be tested by an independent third-party testing facility and will have the paperwork to back it up.
Search for “AB 1953 compliant” on the fixtures of your choice. Most manufacturers, if they want to sell in California, will have an "AB 1953 compliant" FAQ somewhere on their site.
(Previous faucets and fixtures sold and installed before this date do not fall under either bill.)
Links:
SafePlumbing.org: Lead Plumbing - Offers some more explanations and a list of compliant companies.