California’s all-party consent rule
Be careful here — California has strict rules about recording private conversations, and recording the wrong way can actually get you into legal trouble instead of helping you.
California is generally an "all-party consent" state, which means it is usually illegal to secretly record a confidential conversation without the consent of everyone involved. So secretly recording a private phone call or in-person conversation with your landlord can violate the law, even if you are only trying to protect yourself.
This is very different from documenting conditions. Taking photos and videos of your unit's condition is generally fine and is exactly the kind of evidence you should gather. The caution is specifically about recording private conversations.
Because the rules are strict and the consequences serious, you should get advice before recording any conversation with your landlord. There are safer ways to create a record — like communicating in writing, which documents things without the legal risk of secret recordings.
If you are thinking about recording your landlord to protect yourself, a free, confidential review can help you understand the law and the safer ways to build your evidence.
This is general information about California tenant rights, not legal advice. Every situation is different.