An automatic waterer. They are awesome.

It's an Nelson, Automatic Dog Waterer from http://www.dogsunlimited.com/i/724/nelson-automatic-dog-waterer.htm

No drain? No fear of flooding?

wildta
I have had one for years, and in my new home I'm having an incredulous and very reluctant plumber install one under my coffee station in my kitchen for my wolfhound and great dane, and another in my laundry room for my cats (who refuse to drink out of a water bowl that the dane has slimed). I have never had a problem with flooding. There is a shut-off valve (mine will be in the basement) that you can use if the float mechanism malfunctions. There is, however, a need for tiling the backsplash and floor due to the dripping from long tongues.
Let us know how it works out for you!

Here's my farm supply store waterer ($40 plus the plumber's gouging). :)

Thank you so much for these up close pictures!! This helps as I could not really understand it from far away!!