I gave up storing a dump hose in a compartment years ago. The designated one was a rear bumper compartment that totally sealed. It was a tight fit and it made no sense to me to put a wet hose into a sealed compartment. On top of that the hose could never really be totally cleaned so it would stink when sealed up.
Instead I put an eye hook on each side of the camper under the bumper and behind the step. I use cord with snap fasteners to suspend the hose under the camper exposed to the air. The same hose has survived in that position for 10 years and 100K miles. Since the hose collapsed into a relatively small length, I would think I could fit two 10' hoses. If not I would just use a couple more eye hooks and another cord.