Would the city of Waterdeep have lvl 20 wizards or sorcerers?

@Younes_KEWould the city of waterdeep have lvl 20 wizards or sorcerers, or is it rare to have characters that powerful in the realms? They're rare than you might think, but yes, Waterdeep would have a few. Some with public profile, more hiding their full power.

— Ed Greenwood (@TheEdVerse) September 23, 2016