I imagine that I am not the first to discover this, however I have not seen anyone explicitly state this finding. As a result, I'm sharing this hoping to elucidate the mystery. And PLEASE read my comment at the end of this post before jumping to conclusions....
Zuma...is named after a beach in Malibu. It is apparently very popular for wide sands and great surf, and is consistently rated as one of the cleanest beaches in the region. Now, there is the obvious relation of the waters to Zuma's occupation, but the following is why I'm certain that this specifically is the connection. Note its location: California. This presents a clear association to having him speak with stereotypical Californian vernacular. Furthermore, with Zuma Beach's reputation for cleanliness, it makes sense to use the name to promote a positive image.
My Ending Note: I REALLY do not want this to be misconstrued as evidence for Zuma actually being Californian in the show. It is not addressed: please do not use this to represent the standpoint. It IS however a reasoning for his chosen name and character traits. Let us please leave it at that.
Now, let's see who can figure out the significance of Rocky's name. (joking)