Each sorority and fraternity is different, but I think that they all have minimum GPA requirements that must be met in order to be initiated and to be an active member in good standing. Also individual campuses set academic standards also. You can look at each website to see these requirements.
For DPhiE from the website
"Academic Achievement
Each member must maintain a cumulative grade point average of 2.25 on a 4.0 grading scale, and/or maintain an average above the college or university's all-women's average, whichever is higher. Members must individually maintain a minimum cumulative 2.50 GPA on a 4.0 grading scale in order to be eligible to run for or hold a position on the Leadership Team."