Don't cauilk it at your own risk.
There isn't a whole lot holding a pedestal sink to a wall. Plumbers like to "stick" them to the wall.
Inspectors like to see the caulk too.
I find that clear looks better then white.
I will be removing a pedestal sink as a part of a bathroom remodel. Currently it is caulked at the rear where it meets the wall. When I reinstall the sink I am considering not caulking the rear edge since I don't like the way it looks and because it tends to collect dirt like hinge dust from the medicine cabinet. I looked up the instructions for at least two pedestal sinks and they did not mention caulk at the rear, while I have seen it mentioned on at least on DIY web site.
What is the norm for a pedestal sink install? Caulk or no caulk where the sink meets the wall?
To plumbers and some inspectors it a health safety issue,
because by not caulking you are leaving a place for water and bacteria to hide and cause mold, mildew, and lots of nasty
germs to grow,
while some people think of the caulking to sick it to the wall like terry say's it much more of health issue
also like terry say's i use the clear now days, it goes on white but when it cures it is clear !
Caulk it is, and I hadn't thought of using clear caulk. That might be a better option. Of course the current problem might be the width of the caulk and the type used. Some tend to be softer or more pliable and hold more dirt than others.
Looks like part of the problem is that lavatory is not level from front to back. It is 5/8" lower at the front which is causing the gap at the top rear to be wider than it should. I'll fix that when it goes back in. All this time and I did not realize that this sink was not installed properly.
You may want to pick up some toggle bolts and fender washers to suck that basin to the wall before you caulk.
The parts that come with pedestal lavs are nearly impossible to use. For us, it's a trip to the hardware store for the toggle bolts and fender washers, and some 1/4" 20 nuts, which if needed can be taken from a closet bolt set.
There, I've done given away a nother top trade secret.
I found what looks like me sink on the Crane web site.
It looks as though there is supposed to be a hanger bracket. Mine was not hung with the bracket. It is held in with screws into the studs. See picture below. I like the fancy hand crafted copper washers that were provided by the original installer. What do think about this mount? Should I try to locate the hanger? As long as lav is set level and in contact with the pedestal, I think those screws should be enough to keep the lav flush to the wall.