You must be paid 1 1/2 times your regular rate for any hours over 40 in one work week. It doesn’t matter if it’s the second, third, fourth, fifth, sixth, or seventh work day of the week.
california also requires the same pay rate (1 1/2) for any time worked over 8 hours in any work day.
Of course that that doesn’t apply to any occupation that is exempt or different rules may apply to.
https://www.dir.ca.gov/dlse/faq_overtime.htm

