Just one way of providing water and humidity. Look at the Casita from THA (photo on the right with yellow Casita and arrows with explanations):
https://tarheelants....cts/casita-2016
There's a gravity well higher up, a water chamber not connected to the tunnels that usually holds more water that is slowly pulled downward by gravity, seeping through the grout around the tunnel chambers. The ants can drink from the moisture on the grout as well. Lower down is a "water tower" which is a mesh covered mini Petri dish that also provides water and humidity.
I'm doing the same in my new nests but only on one side of the nest so I can have more of a gradient from one end to the other. Really, they're pretty small nests so I'm not sure how much the humidity in the air will change through the nest but the side with the water well and tower will be more wet than the other end even if the air in the nest has a uniform humidity. The ants will choose whatever is best for larvae vs pupae.
THA's larger nest usually have multiple water towers and gravity wells as well as "nest mates" that can add additional moisture or sugar water if needed.