According to the California Supreme Court, there are 8 factors that can be used to determine whether your employer is exerting enough control over you for the time to be considered working hours: whether you were required to live on the premises or work site, whether there were excessive geographical restrictions on your movements, whether the frequency of calls back to work were unduly restrictive, whether your fixed time for response was unduly restrictive, whether you could easily trade your on-call responsibilities with a coworker, whether using a pager would ease the restrictions, whether you actually engaged in personal activities during the time spent on-call, and whether the time on call is primarily spent for the employer and its business.