Leah These tubs with the sloped lip may be pretty hard to find outside of antique markets. More basic galvanized tubs can be found at most farm supply/feed stores.
Leah Unfortunately, I have no real answers since this is clipped from a magazine. My assumption would be that you fill it yourself (buckets or hose) and that it has a pull or screw plug in the bottom. Of course, you could plum a water source if you wanted to. Our barn has a regular garden spigot (like this: http://3.bp.blogspot.com/-qmfguhDAgo4/T57rc0EtilI/AAAAAAAAA7s/-Zb-4ed741g/s1600/DSCN1025.JPG) that is plummed to the hot water tank.