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On my 2018 24RBS my two white fresh water overflow hoses are located behind and to the right corner of my front entry steps.
Also, fresh water overflow hose (any model) are known to siphon out water while in-tow, so some of us have installed open/close valves or caps (end of hose) to address this "while-in-tow" water loss issue. BUT, one must remember to open the valves (or remove the caps) when filling and/or using the fresh water tank(s).
The grey tank doesn't have an overflow hose below the TT.
Hope this helps.
2016 GM 2500HD 6.0L/4.10
2018 Jay Flight 24RBS
2002 GM 2500HD 6.0L/4:10 (retired)
2005 Jayco Eagle 278FBS (retired)
1999 Jayco Eagle 246FB (retired)
Reese HP Dual Cam (Strait-Line)