Dual waste valves on my new(er) rig - can I combine them?

I have that adapter the first responder posted. and it works well.
However I don't use it.. I got one of the sewer outlet caps with a hose coupling (3/4 inch garden hose) and put that on.. I use a 3/4" hose (Gray) for the "WASH ONLY" tank (The one without the kitchen sink) and a matching coupler on the ground elbow at the hole in the ground.

To avoid any confusion... the hose is GRAY (25' as well)

I also have a 50;' Black 3/4" hose for the macerator for when I need to do it that way

phemens wrote:
To clarify, it looks like I have a black and grey tank on each outlet, so if I use the ‘Y’ I could run both at the same time (both black, then both grey)?

I run the same setup, the only problem I have is the galley dump valve is located under the front slide out. Not a problem weekend camping but irritating long term. I usually leave it open when set up for an extended stay and close it a week before pulling out to get a good flush.

I have never stayed at a campsite with full hook ups. I guess I'll have to see how big a pain it is to move the hoses from one to the other at dump station, worst case it's a candidate for a future project. Thanks

BFL13 wrote:
If you had the clear elbow to see what is leaving the black tank into the sewer hose, AND a tank sprayer, you would see that on the second go, there is lots of "stuff" (lots of toilet paper included) going by the window then too. You would never again say that the black tank only needs to be dumped once.

Of course it only needs to be dumped once if you are in a hurry, as long as sooner rather than later, you get it properly flushed out. If you don't, eventually you will be trying to unclog the whole thing by poking something down the toilet, and all that kind of fun. :(

So I've been somewhere around 14 years with "only dump once". I'm of the opinion I don't need every little scrap of TP out of the tank - I'm not using it for storing drinking water, I'm using it to store more chit next trip out. 5 gallons of water sloshing around in the tank while I'm driving will take care of any remnants remaining just fine.

For the OP:

If you are sitting at a campsite with full hook-ups and staying for any length of time, tying all the outlets into a single hose with Y's is the way to go.

Otherwise (sitting at the camp site), you need to make sure you have enough hose to reach the farthest outlet to the campground sewer pipe and then simply move the hose from outlet to outlet.

If dumping at a dump station, and your outlets are a distance apart, about the only option is to dump the first one, move the trailer, then dump the second one. Considering mine are fairly close to each other, I move the hose from one to the other. I only use the Y set-up in the photo above when parked for more than a couple days.

You do have the option to experiment with a more permanent plumbing install on your camper and tie them all together. If you do, you need to consider how much of that pipe hangs below your trailer frame, and don't go lower than the top of your axles to you have some sense of assurance nothing will get knocked off when traveling, especially if you experience drives and parking lots with excessive dips and hills. That's the only risk I see in adding extra pipes, unless you can get it all inside the width of your trailer frame.

Either way, good luck.

Earl E wrote:
...it seemed that many of the more expensive RV's did tie them together...

Late model fiver next to me has three tanks, three valves, one outlet connection. It's a Rear Lounge, so the Mid Kitchen is actually very close to the forward/upper Bedroom and Bathroom. That actually brings the plumbing close together. So Floor Plan might have something to do with the connections. Rear Kitchen could put the tanks or connections a good distance apart.

guess i lucked out here. Mine has three holding tanks and they are all plumbed into one single dump outlet. :C

Not quite the same but in a previous trailer I had two gray tank valves. It was a pita moving back and forth and I did run a pipe between the two and tied them together. It worked flawlessly. In my research it seemed that many of the more expensive RV's did tie them together. I don't see why two blacks would be any different. I'd give it a try. It was worth it for me.

Lantley wrote:

phemens wrote:
Thanks Dutchmen Sport, good idea. Do you let both outlets rip at the same time?

THe black tank only needs to be dumped once. It's easier to just move hose vs. setting up the wye and all the other hoses.

If you had the clear elbow to see what is leaving the black tank into the sewer hose, AND a tank sprayer, you would see that on the second go, there is lots of "stuff" (lots of toilet paper included) going by the window then too. You would never again say that the black tank only needs to be dumped once.

Of course it only needs to be dumped once if you are in a hurry, as long as sooner rather than later, you get it properly flushed out. If you don't, eventually you will be trying to unclog the whole thing by poking something down the toilet, and all that kind of fun. :(

phemens wrote:
To clarify, it looks like I have a black and grey tank on each outlet, so if I use the ‘Y’ I could run both at the same time (both black, then both grey)?

Realistically you can only dump one at a time.
There is no need to ever dump simultaneously. With that in mind I just move the hose. No need to get out a wye and set all that stuff up.
In my case the only tank that I need to worry about is the grey water tank that the shower goes to. All the other tanks will last the entire trip.
I attach my sewer hose there until it's time to leave.
Then I move it to the rear connection for the galley and rear bath which are never full.
YMMV