1-Sometimes they install an access door inside an exterior baggage compartment. Those compartments are often very dark in color . Use a flashlight to be able to see the hard to find door.
2-Water pumps are usually close enough to the water storage tank and water heater. Look to remove a screwed in place cover panel. Maybe below the fridge ?
I assume that you lifted the bed ? I think the freshwater tank and some of the plumbing is located there.
At the 1.34 mark on this video it shows a hidden panel. Something to check if the other locations failed.
https://youtu.be/sW0l3KEsMYQ