Hi Sharpe Tunes,
Just out of curiosity, I just went and measured my 2019 22M:
Ground to Tank Fill Connection = 44"
Ground to top of fresh water tank = 52˝"
So, the top of the tank is 8˝" higher than the Tank Fill Connection. So mine must have a one-way valve too. You learn something every day, right?
Thanks, Eagle5
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2019 Minnie Winnie 22M on an E-450 frame