I find that they're similar to Antaresia when it comes to sloughing. They're not thick-skinned like a Woma or Death Adder, so they benefit from higher humidity when sloughing, but then again, so do Carpet Pythons, and the ideal conditions are the same, it's just that something like a Carpet Python will cope with the lack of opportunity to get humid better than things like Antaresia and Waters. If you want to be nice to your snakes you can stick a hide box filled with slightly moist sphagnum moss at all times and whenever they want to get humid for any reason they can go in there. In the wild all snakes have this opportunity, even out in the desert it's like that when they go underground (which is why things like Womas manage to incubate their eggs in the middle of a harsh desert).
Even with small water bowls I very rarely have any trouble with my Water Pythons sloughing, no more than Children's Pythons.