Compared to larger schools, Greek life at Santa Clara plays a pretty low-key role in the campus social scene. This is due in part to the fact that the University stopped formally recognizing fraternities and sororities a little more than 10 years ago. But while not affiliated with the University, Greek organizations still maintain a presence in SCU's social life.
Sororities and fraternities not affiliated with Santa Clara University are housed off campus, though not in the mansion-style houses of larger universities. Because the houses are smaller, only officers and select members live in the official "house." Other members live separately, either in other off-campus houses or in the dorms. Because Greek life has such an informal presence on campus, there's very little social pressure to join. Those who want to join can, and those who don't won't find their social lives negatively impacted by choosing not to.