The Macmillan Dictionary entry for back up reads
- [intransitive/transitive] if traffic backs up, or if it is backed up, the vehicles are in a long line and waiting to continue moving
4a. if a toilet, sink, or drain backs up, or if it is backed up, water cannot flow through it because something is blocking it
4b. if a system backs up, or if it is backed up, it has slowed down or stopped working because there is too much of something for it to deal with
Here are these meanings common in American English? Are they used in daily life conversations?