Well, Bobert,ol'-buddy, ol' expresedintal-candidate =to-be, I would had been talking bout this with you sooner, but I can barely spell hydrostatic pressure, let alone fix one.
But here I was drinkin' my Budweiser and thinkin' on yer dripping problem. Then I started thinking on the "bigger picture" as they say.
Just suppose you fix this little dripless hose problem. About 5 months from now yer trailer guest gets up in the middle of the night to take care of business. A few minutes later, they hit that little leever to git rid of the product of their labors and ...NOTHING HAPPENs. Why?
Because it's tha middle of winter and yer big ol. 450 gallon tank has gone and froze up solid.
Sounds like you need a 5 point action plan to research tha best way to face this new crisis.