I can understand that the UC system does not allow transfers to have more than 70 Semester Units when transferring from a community college. But what about in the case of having a total of 90-100 combines, which includes the IGETC (which makes up like more than half of all my work at the 2 year institution? In my case, as a STEM major, I will be staying for perhaps 3 years.
Are they all from a community college? If so, you’d be fine. They will only take 70 units and the rest you would use to clear pre-requisites, satisfy degree gen ed requirements etc. You’d run into trouble at time of application if some of those were upper division units, and no units from CC could ever be considered upper division. So be careful if you’re thinking of taking summer classes at UCs, etc.
There are many threads on here that discuss the issue at length, you should search through them. Also, talk with a transfer counselor as they deal with this issue every year and can offer solid advice. It’s kind of a confusing topic. I have something like 120-130 sem units from CC and I’m transferring just fine, so you’ll be fine. 
they cap the units towards UC graduation at 70. The rest of your classes can still be used to satisfy requirements.
Note that for many STEM majors they recommend that you don’t complete IGETC so that you can finish college in 4 years. And some majors don’t even allow IGETC to satisfy general ed. All explained on the UC website.
What 4 year institution are you transferring to? And what’s your major? @ananguiano
What’s your major? @mikemac also, I can understand that. But just in case of changing my major or some other purposes, I intend to satisfy all 5 areas of IGETC in my Community College.