How Should RV Waste Gate Valve Be Oriented When Being Installed

Updated 11/17/2025 | Published 12/05/2024

Question:

I am redesigning my original RV plumbing for my gray and black tanks. I was contemplating putting gate valves in a horizontal position, but it occurred to me that it could be a problem. Most that I have seen are oriiented vertically, some perhaps at about a 45 degree angle. I know that my fresh water tank valve is horizontally aligned, and its never been problem. But with gray and especially black, I could see potential for solid matter to settle on the gate and potentially cause a jam in the mechinism. Do you think it matters?

asked by: Mike O

Expert Reply:

Hi Mike,

Gate valves should be almost perpendicular between the ground and trailer frame. There's a slight angle down so that gravity will help empty the tanks but we're only talking about a few degrees for most setups. Placing it so that the gate is facing down would likely put more pressure on the gate, depending on the amount of waste in the system, and would likely leak out as the seals wear. Having it in the normal orientation would lessen the amount of waste water and solids sitting against the gate, putting less pressure on it and the seals. When you open the gate the seals have the opportunity to move slightly in the housing which can allow waste water to leak into this gap and into the waste housing, which will also eventually start leaking or can bind up the handle.

Realistically you would want to have the handles point up so that there's less of a chance of waste water and solids leaking past the seal and getting into the housing. This doesn't always work with every setup though so I would try to install the valve so that the handle is sitting between 90 and 180 degrees to the pipe.

The fresh water tank would have just a clean out drain so that you can empty out any unused water and a pump to push water through the RV's system so the orientation needed for this tank isn't really the same.

expert reply by: Kevin C

Jesse M.

11/17/2025

Hey Mike, how did your plumbing redesign go with the Valterra waste valves? Did the near-vertical orientation help keep things flowing smoothly from your gray and black tanks? Your update could make it easier for others planning a similar setup.