The relevant code for how California restriction is calculated can be viewed here: https://github.com/OpenSprinkler/Weather-Adjustment/blob/master/application.py#L336-355
Specifically though, it’s adds the amount of rain over the past 2 days and the current day. If this is greater than 0.01″ of rain, then a restriction is applied. This effectively changes the watering level to 0%. Once the flag is cleared, the watering resumes.