I'll give this question a shot, based on my 2004 PC 2350. The simple answer is that there are three places to drain the fresh water from the coach. To drain the water lines, there are the winterizing valves. These just drain the water lines, not the tanks. The location for these valves should be discussed in the manuals. Mine are located in a storage bin. To drain the fresh water holding tank, there is a valve near the bottom exterior of the tank. The valve is connected to a tube that drains the water onto the ground. This valve is also accessible from a storage bin. To drain the water heater, there is a drain plug located inside the water heater panel at the bottom of the tank. It's probably a plastic plug with a 7/8 inch hex head. Remove the plug and the hot water drains out. Refer to your water heater manual for all of the warnings and instructions before removing the plug. Don't forget to properly replace the plug and shut all of the valves before you use the RV again.
