Parents are responsible to notify school when their child is, or will be, absent.

California Code of Regulations (CCR). Title 5. Section 306 states:
Absences should be cleared the same day they return, but law extends to the next day.
Absences will be changed from unverified to unexcused and subject to truancy laws when a parent fails to notify the district about their child's absence. 
Benicia, like most districts, has a 72 hour policy.