Waterfall cave is unlocked when you progress through the main story. I forgot exactly when becuase I found it a long time ago. Sorry. This is all I remember.
There are 8 floors in Waterfall Cave.
In mystery dungeon Red/Blue, you can recruit it at Waterfall Pond, but first you need to obtain HM Waterfall from Solar Cave. Then, once you recruited it, at its friend area, choose become leader.
Waterfall Pond has 19 floors. You need the HM Waterfall to enter the cave.
I haven't seen azurill in Pokemon Mystery dungeon explorers of time a lot. I gues you could find azurill in one of the water related dungeons. (Example: Waterfall Cave, Brine Cave, etc.)
you do a few jobs and you go to the waterfall cave!
In Pokemon Mystery blue Dungeon, after you beat Rayquaza, you should be able to go to a dungeon called solar cave. There you will find the HMS surf, dive, and waterfall. In sublevels 10-20 you should find a few Chimechos. I have one Chimecho
A dungeon is a cave on pokemon mystery dungeon. It is a level with a series of floors/rooms and the object is to get to the end of the dungeon.
any level there are 10 floors but if you are a fire type get a electric type!
In Aegis Cave
In solar cave
There are loads in western cave.
entei