If it is not in an exterior compartment the first place I would look is under the bed.
Recommend you contact Thor, if you haven't done so, and ask for the fresh water and waste diagrams for your coach. They should show you the general location of where things are located and how the coach is plumbed.
US Army (Ret)
2020 Entegra Accolade 37TS
2019 Jeep Grand Cherokee Trailhawk (Toad)
FMCA - F432054
I cut a trap door into the bed platform and added a couple of hinges. To get at the pump for winterizing, just have to slide the mattress off toward the front of the coach and open the hatch. Used Velcro to secure the panel under the kitchen sink that covers the water heater bypass. I don't believe you should have to unscrew things to perform ordinary maintenance tasks.
I don't believe you should have to unscrew things to perform ordinary maintenance tasks.
For the 34F, the access panel to the water maintenance bay under the bed is about 2' by 2', it easily could have been designed as a hinged door adjacent to the hinged door covering the storage compartment. Good idea, I may convert mine into a door top also.