How are the black and gray water tank vents and drains attached to the tank?

[Steveo57]

If you have to drop a tank down how do you deal with the drain and vent lines penetrating the top of the tank? Are they glued in, clamped on or what ???

My tanks are tight against the floor under the trailer and there's no access to the top of the tank where the drain and vents go in without tearing open a wall.

[fjr vfr]

Why do you want to drop a tank? I believe you would have to open walls to access your drain and vent lines. I remember someone cutting the pipes and the connections being glued with pvc glue. You would use sleeves and glue to re-connect.

Check on Youtube, I'll bet someone has a video.

[Frank G]

I think the factory ones are spin welded together. The flange to tank. If you are removing and reinstalling leave enough room (when cutting) to use some no-hub connectors or glue fittings.

[Steveo57]

I don't need to drop a tank. I was just curious after poking around under my trailer today and seeing that the tanks are tight up against the floor. There's no way to access those connections on top of the tank from underneath. They must be plumbed up before they cover the walls just like a house.

From the inside I can see large holes in the floor where the vents and drains come up into the trailer and wanted to seal them up from underneath to keep critters out. But it will be difficult to get access to do that from the inside. I guess since the tanks are tight up against the floor there's probably not much that could slip into the trailer through those holes anyways.