Emptying black and gray tanks

It really doesn't seem like a lot of trouble to me to have two separate drain valves.  I thought about the thing Grandpa Hiker suggested but the additional plumbing and the logistics of getting it all to work satisfactorily convinced me to continue with two valves.  Yeah, it's technically a little more effort, but it's not that big a deal.  My opinion anyway.

TT

I'll second that for Tars. It is what I have been doing since we got ours in December 2015. I've had to get a wrench to try to help get the connections on and off as my hands are getting pretty bad with arthritis and I don't have the grip strength I used to have. Otherwise, it is not a big deal to switch the hose from the black to the gray to drain the tanks.

The worst place I ever dumped was in Benson, AZ at a truck stop. I needed to dump the black and gray tanks. Unfortunately, the drain was set up on a curb which meant that it was about the same level as the valves. It was interesting lifting the hose to try to get the last of the liquid inside to drain before disconnecting. That was the only place I have encountered that though.