Under 200 square feet, usually no permit
Santa Clarita's building code lists drywall repair among the jobs that need no permit, as long as it stays under 200 square feet and isn't part of a fire-rated assembly. A doorknob hole or the patch behind a towel bar that pulled out sits far below that line. Santa Clarita Building Code, Section 105.2.3
The exemption stops where the repair cuts away part of a wall or moves pipes and wiring. Rated walls are the other exception. In a house that's usually the wall or ceiling between the garage and the rooms, and in a townhouse or condo the wall shared with the unit next door. Check with Building and Safety before that board comes out.
