The site plan for this was filed in late November and stated that this was 23-stories. But it wasn't clear if that included the underground parking levels. More info has since been added to the site plan, and we have some confirmation on the height. The pool is on the 19th level, which is most likely the top level based on the height limit for the area. And there has been no indication that a zoning change is being sought for 23-stories.
Here's the site plan:
https://abc.austintexas.gov/web/perm...ertyrsn=310352
Here's the location on the NW corner of Rio Grande & 22nd from Streetview: