Emptying Fresh Water Tank

not that this is important, but on my last trip i unscrewed the fw drain cap and nothing was coming out.  so i pondered!!  for a bit and realized that that insert (i guess it could be considered some kind of washer that is inside the cap) stayed in the hole.  pulled it out and wallah.  just thought i would pass this along.  GO PACK.  hogone

Opening the taps allows air into the system, so it does help the water to drain faster. Think of it as inverting a large bottle with a very narrow neck. When some water drains, it reaches a point where some air has to bubble up through the neck in order for more water to drain. Opening a tap is like if there were a valve at the top of the bottle that was opened. Water would then gush out as the partial vacuum would be broken.

However, there is a vent on the fresh water fill. That should allow air into the tank so that when the drain cap is removed, the tank will drain and not pull a partial vacuum and stop draining.