Well, I looked up something in terms of real world money if this helps you excite your players. In real world currency, gold is traded and priced by troy ounce rather than pound. It’s about $1,778.70 per ounce currently in USD. 12 ounces in a pound make it about $21,344.40 per pound at current rates. The Vault of Dragons’ entire treasure horde is 10,000 lbs in solid gold. That means that we’re looking at $213,444,000!

Of course, that’s IF you let them keep the whole thing. If you follow the book, the best legally they’ll get is 50,000 gp, which is 1,000 lbs. They’re still millionaires at $21,344,400, but the point here is you now have an IRL starting point for what its worth.

Now, for my Waterdeep, I want to compare it to New York City. Any heavily populated city will do, but New York is easy to think of. The current budget of New York is about $6.1 billion. That means the Vault is about 3.5% of the city’s budget. Not a lot, but not something to sneeze at.

Alternatively, you could make it much more so, such as making the City Watch underfunded, the guilds harsher on those who try to shirk them, and more unemployed beggars on the streets of the Field Ward.