What is the default Syslog facility level?

The answer is Local7. The default Syslog facility level is Local4 that corresponds 20 on ASA. You can see the facilities on the Syslog server Local0 to Local7 and the default is Local4. By using the facilities, you can organize all the received syslog messages from different sources on a syslog server. It also depends on the configuration you are logging what syslog facility level you should be using.

As the user, you can easily verify by typing in ASA#sh logging Syslog logging: enabled Facility:20. This method can help you in checking your Syslog level to be able to use the correct formula and command. Just remember that the server ranges from Local0 to Local7.