I use this one via SSH to have output in MB and GB which makes live easier.
du -h --max-depth=1 /path | sort -r -k1,1n
So for the biggest homedir:
du -h --max-depth=1 /home | sort -r -k1,1n
Change max-depth (and if needed other things) to your own need.
So with /home/user you can find the biggest dir in a specific user account for example. And so on.