How time consuming are sororities?

I’m going to be majoring in Biology and doing a track for pre-med. I know I’ll have a lot on my plate just with classes alone. In addition to that they recommend joining a club for pre-med (or other pre-health clubs) and I will need to do other shadowing, internships, volunteering etc during the school year or during summer. I really want to join a sorority, I just don’t if it’s in my best interest. I have about 3 years of college give or take. I don’t want to make a that (expensive) commitment and not be able to do anything or ultimately dropping.
So how time consuming are sororities? What (possibly) is mandatory and what is optional? etc.
Thank you!

I don’t know how time consuming they are, but you’d probably be able to get some volunteering in as part of the sorority. Many of them if not most organize philanthoropic events or go places to volunteer.