Class C freshwater drain?

It's a bit of an unusual design, I think, and perhaps could have been done a little more elegantly.

I don't think you have any real danger of cross-contamination here. Water would have to flow up the drain outlets and into the fresh water system to cause any difficulties. If you're draining, the water is flowing in the wrong direction. If you're not draining, the drain valves are closed and water cannot flow up through the closed valves. Even if they were left open, it would require a vacuum in the RV water supply system to make the water flow the wrong direction, and there's not much of a way for one to form.

(In a multistory house, it's somewhat of a different matter as a heavy water usage at a low area can quite easily cause enough of a vacuum at the upper stories to draw water backwards, which is why air gaps or other backflow prevention devices are required on plumbing fixtures.)

I gave up a long time ago. I fill the fresh water tank using the white hose, but I only use it for anything that goes on the outside of me, like showers or flushing the black and grey water tanks after I've drained them. I'm waterproof. For water that goes inside of me like drinking, cooking, or in my case soaking my teeth overnight, I buy gallon jugs of distilled water at Wally World. They're cheap and readily available.

Thanks for the help... I have 1 or 2 minor leaks in the drain system (pretty sure gray as soapy) and a black water tank that is visibly dented from the wheel-well side. For now I'll clean up with some bleach solution and just be really mindful while emptying FW. (the caps are a bit whiter because I already hit them with some bleach)

Eventually I think i'll get the tanks replaced, maybe they'll be willing to re-position the freshwater drains away from the drain a bit :-)

I would be more concerned about all the filth on the FW drains, than the proximity to the gray tank drain. I would clean those thoroughly and disinfect the outsides before draining, since they look so nasty.

You could transfer some of that filth up into the drain in the process of closing or opening the drains. If it's while closing them, and you refill with fresh water, you could have germs growing in the drains and moving into your FW tank.

For the same reasons, I would clean the outside of the gray tank outlet as well.

Just wash the entire area down with some soap and water with a good slug of bleach in it, and rinse well.

If the drains are capped while you are draining the gray tank, you shouldn't have any issues with contamination from the gray water itself.

My low points are on the other side. I dunno - if you're draining water w/ bleach, it's flowing *out*, I probably wouldn't fret myself too much.

Maybe wipe everything with those Clorox wipes.
Or soak things down there with some water and Lysol and then do the work?

Image for context.



http://s23.postimg.org/b994u7857/IMG_20160220_111322.jpg

Also yeah, the slide valves seem to leak... she's got some issues to fix at 10 years old :-\