The black water flush go's from out side to tank (black). I just blow it out. Washer dryer you can run Rv anti freeze though it or take off hose's at back close vale's dump Anti freeze in washer and run till pump out add little more. Go to washer Manufacturers web sit and get there instruction s on winterizing it.

Thanks for the info Carl17. I'll look a little closer this next season. We did have bitter cold weather here in ND, but luckily so far, I haven't discovered any leaks. I'm also concerned about two other areas.

One is the black-water flush tubing that I have begun to wonder if there is a one-way valve in the line to prevent black-water fumes from entering the fresh-water compartment hatch (and drift into the fresh-water filler). If there is such a valve, it might back up residual water that could freeze.

The other concern for winter drain is the washer-dryer. We didn't add any water to the assembly, but looking back, I believe I vaguely recollect our dealer said they tested the washer-dryer which means the machine may have still contained some water. If so, and any damage ensued, we will probably normally never know since it is doubtful my wife will ever actually use it.

Wes

I use the air to blow out water lines than RV antifreeze pump through . Which save me before i found low point drains. when ifound low point drains they still had water in them. But lucky the real cold weather did not come. FYI