Our 15-ft RhinoFlex fits in our bumper. But I keep the 10-ft extension in a plastic Rubbermade bin (along with 45-degree fitting and black tank flush hose).
I have noticed rust on the exterior of my hose from being stored inside the bumper (and the end-caps are vented).
2015 Jay Flight 32 BHDS (Elite, Technology, Thermal pkgs, 50-amp)
1999 Ford F-250 7.3L Powerstroke 4x4 Lariat Crew Cab SRW 3.73
6.0L Upgraded Transmission Cooler
Autometer Gauges (EGT, Trans & Water temp, Boost)
K&N Cold Air Intake; MBRP 4" Turbo Back Exhaust
Curt Class IV Receiver Hitch
Prodigy P3 Brake Controller; ProPride 3P Hitch 1400#