2011 Solera S. The fresh water holding tank on mine...open large bay door street side. There is a panel about a foot square with a handle on it. Remove the panel and reach as far down as you can towards the left and there is a valve. This drains the fresh water tank.
The low point drains are located directly behind the steps. A red pipe and blue pipe with screw off caps..Remove the caps and you can drain the lines (only). This does not drain the fresh water tank..
In the electrical, city water, sewer compartment is a hose that just "lives" there and this is the intake hose for winterizing. Turn the winterize lever, insert the hose into a jug of rv antifreeze and turn the water pump on and it will suck water into the the pipes...NOT THE FRESH WATER TANK.