Anyone in SoCal who listens to the radio or pays attention to local television ads should recognize the tongue-in-cheek meaning behind Jack's name plate, which is an exasperated response to the announcer's botched attempts at getting his name right. Jack Stephanino, Jack Stephonsky, Jack Stephanovich. According to Reeves Journal, the campaign came about organically because the announcer really did keep making mistakes.
In case you missed it, here's the commercial courtesy of the actor portraying the plumber, Rob Brakenridge:
Further good reads about this commercial at losanjealous.com.
Or maybe you've seen one of their vans around, featuring the phrase incorporated into the company logo. This one was snapped by Flickr Pro, SoCalMetro:
An interesting bit of trivia gleaned from Jack's brother Harold's epitaph (or at least it was news to me seeing as I'm not up on local plumbing history) is that "Adee Do!" (established in 1949) is part of the Jack Stephan empire (established in 1946.)
Which leads me to wonder if competitor Mike Diamond "The Smell Good Plumber" has a pre-arranged burial spot. There's a built-in grave hunting joke at the tip of my typing fingers tongue, but I'm not going to go there.