Building age is the biggest clue
The age of the building is the biggest clue. Lead-based paint was banned for home use in the United States in 1978, so rentals built before that year are the most likely to contain it. The older the building, generally the higher the chance and the higher the lead content.
Homes built before 1978 may have lead paint on walls, trim, doors, window frames, porches, and railings. Buildings from before the 1950s are especially likely to have used lead-heavy paint. Rentals built in 1978 or later are much less likely to contain lead paint.
Even in an older building, lead paint that is intact and in good condition is a lower immediate risk than paint that is peeling, chipping, or on surfaces that rub together, like windows and doors, which create dust.
You usually cannot tell whether paint contains lead just by looking — testing is the only way to confirm it. If you live in an older rental with deteriorating paint, a free, confidential review can help you understand your rights.
This is general information about California tenant rights, not legal advice. Every situation is different.