Parr8hed, my 2007 Roo 23SS has the valve like your pic shows.
Your pic is of the FW tank drain.
The low point drains for H & C water lines have the same valve to drain.
Mine are under the sofa.
Not sure where they are in the 17.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC