Connecting Gray waste to Black waste

I had a Colorado that had 2 gray tanks and 1 black with 2 dump valves. I previously used a wye. Then I decided to put a cap, with a hose fitting on, the one gray dump valve and connected directly to the valterra dumb elbow that had a hose fitting on it, too. But first, I had to punch out the plastic stopper on the elbow. I also had to cut off the male end of the hose and put on a female end. That way it could connect to both.

I was able to dump the one gray tank, with the hose. All I had to carry was a dedicated "gray" hose, instead of another "stinky-slinkly.

One thing to think about is most of the time the tanks are always mounted between the frame and is higher than the exit point of the drain so should flow fine, Mines flows very well and I ran it about 14 ft over the axles also. no problems.

xPIXx wrote:
I am going to do this also but have around 16' to run. Has anyone seen any problems with long runs and the amount of drop in the pipe to get good flow? Any interference with suspension by going over the axles?

1/8" per foot is usually quoted as the minimum fall for a drain pipe. In your case that would be 2". That said, I would go down to half that if need be, any water left in the pipe will clean it while traveling. I plan on doing this project over the winter.

I am going to do this also but have around 16' to run. Has anyone seen any problems with long runs and the amount of drop in the pipe to get good flow? Any interference with suspension by going over the axles?

Yea I had a wye too, but it was a lot of extra sewer hose to carry and seemed like every time I hooked up at a site I had to re-engineer the sewer hose hookup, so that why I just ran a line from my rear galley to connect to then other dump point. now I have less hose to carry and don't need all those extra fittings.

My camper has 5 tanks and 2 sewer hookups. I use a "wye" and just more sewer hose when I'm at a full-hookup site:

Thanks, Okiejoe. I'm going to hit it this weekend.

yes, I have 2 gray tanks and 1 black and 2 drop points so I just ran an inch and a half pipe from the rear galley tank to the mid point drain where the other gray tank and black tank drains, works great and now only have one drain point to connect to dump, used to have to dump main gray and black tank then pull forward to dump rear gray tank.