From the PDF introduction
A Web Enhancement for City of Splendors: Waterdeep
City of Splendors: Waterdeep provides the most indepth description to date of the famed city of Waterdeep in the FORGOTTEN REALMS Campaign Setting. The book also offers four new prestige classes appropriate for residents of Waterdeep, plus a variety of new feats, monsters, and magic items.
Noble Houses of Waterdeep provides a thorough and up-to-date break down of Waterdeep’s most important nobility. The nobles detailed he redo not rule the Waterdeep region, but they do own much of the surrounding countryside. For more information on these noble houses and their influence on the city, see City of Splendors: Waterdeep.
As always, feel free to adapt the material presented here as you see fit to make it work with your campaign.