The city of Sacrament is a spiraling, winding, multi-story settlement that's easy to get lost in, especially if you're searching for a drunken guard passed out next to the fountain in No Rest for the Wicked.
No Rest for the Wicked – 10 IMPORTANT Things You MUST Know Before You Play! (Early Access Guide)
The in-game map for No Rest for the Wicked doesn't feature many landmarks, so you'll only have one quest marker to aim for if you're actively working on the Of Rats and Raiders quest. Finding the fountain comes several missions into the questline, after you've defeated Garok and spoken to a captured Odessa.
Here you will find the fountain from No Rest for the Wicked.
If you're looking for the fountain with the drunken guard, as described in the Of Rats and Raiders questline, your best bet is to head to the northeastern corner of Sacrament, in a secluded lower part of town.