California credible witness requirements 

If you are a California notary public, and you are at a signing where the signer doesn’t have a current government issued photo identification document, (or EXPIRED is okay if issued within the last five years) you will not be authorized to notarize the signature of that signer without the use of credible witness(es).
 
When can a California notary use credible witnesses?
If the signer has no identification, or if it is going to be very difficult to obtain (perhaps it got misplaced and is very far away), then you can use one or two credible witnesses depending on whether or not you know the witnesses.
 
When can I use only 1 Credible Witness?
If the Notary in California knows the credible witness relatively well, and the credible witness knows the signer’s full name (without you having to tell them the complete name), then you can use just 1 Credible Witness
 
When can I use 2 Credible Witnesses?
If the California Notary Public doesn’t know the Credible Witness, then you need to depend on the Oath of 2 Credible Witnesses who know the signer’s full name.
 
Identifying the Credible Witness
You need to check the identification cards or documents of the Credible Witnesses. If they don’t have any, then you can not use them.  They need to have current, (or EXPIRED if issued within the last five years) government issued photo identification with a physical description, signature, serial number, and expiration date.
 
Oath of Credible Witnesses in California
The California notary needs to have the Credible Witnesses (one by one) swear under oath that they will tell the truth, the whole truth, and nothing but the truth.  Then, ask them what the name of the signer is who you are pointing to.  If the answer is, “Joe”, then make sure to ask if “Joe” has a middle or last name that they are aware of. If they can’t answer this question, then perhaps they are not the ideal witness for you!
 
Documenting the Signature of the Credible Witness in your journal.
It is required by law to document the signature of the Credible Witness or Witnesses in your journal.  Have them sign in the notes section, NOT the signature section.  Have the document signer sign in the signature section.  It is optional but recommended that you also document the printed name, address, phone number, and identification information about the Credible Witnesses in your journal.
 
If the idenfication is expired – what is the issue date?
On California drivers licenses, there is an issue date documented at the BOTTOM of the card.  This date is not labeled as an issue date, but it is clearly several years before the expiration date, and you can logically deduce that that was the issue date.
 
Get a thumbprint? It is a stronger proof of identity than anything else!
If you are identifying a signer in California based on the oaths of credible witnesses, I would strongly recommend getting a thumbprint of the signer in your journal.  Although only required by law for Deeds and Powers of Attorney notarizations, the thumbprint is a much stronger proof of the identity of the signer than the Oaths of a few people who hardly know the signer.  Please keep in mind that in rural Tennessee, you probably know your neighbors well, and your family’s have probably known each other since not far after the Mayflower landed.  But, in urban or suburban-sprawl California, you probably don’t know anyone well because people tend to not know each other in California.  Credible Witness rules were created a long time ago when people used to know each other a lot better.

You might also like:

Credible Witness notary resources and information
http://blog.123notary.com/?p=21404

A new California notary law
http://blog.123notary.com/?p=3054

California e-notary rules
http://blog.123notary.com/?p=2077