File watcher limits can be annoying and most online resources just tell you to increase the system limits. I'd rather fix the issue at the root and find out which processes are using the inotify api.

Thanks to Pauli Nieminen, in this StackOverflow thread for the following snippet:

ps -p $(find /proc/*/fd/* -type l -lname 'anon_inode:inotify' -print 2> /dev/null | sed -e 's/^\/proc\/\([0-9]*\)\/.*/\1/')