When serving a tenant with a Colorado Notice To Quit, must the Certificate Of Service of the Notice be notarized, either before or after serving the tenant?
The notice to quit doesn't have to be notarized, and a certificate of service by mail is typically not notarized, but, proof of service by personal delivery usually is notarized.
The issue is how to prove that the notice to quit was delivered later on. If the return of service is notarized and filed with the court it can enter judgment (either a default judgment or a judgment on the merits) without separate testimony from the process server in most cases. If it isn't notarized, someone with personal knowledge of whether or not the notice was really delivered will have to testify to establish this fact, and establish that the document tendered is authentic with some kind of testimony.
To avoid this inconvenience, the better practice, although not strictly speaking required, is to notarize the certificate of service involving a notion to quit in an eviction action between a landlord and a tenant.