I also have a 25.4, the fresh water tank drain is under the bed. Lift corner and foot of mattress and prop it up with slide lock bar, remove the one screw on hinged lid, throw screw away or save it as a spare, raise lid and you will now see the fresh water tank, there are 2 valves next to the tank, the one on the left is the drain valve. It looks like a shut off like you would find under a sink or toilet in your house, the port (hole size) inside of this valve is small so it will take some time to drain, when my warranty is out I will be replacing with a full port ball valve. Welcome and I hope you enjoy your coach as much as my wife and I do.
__________________
|