Installing black water holding tank

karma13 wrote:
We are installing a new black water holding tank and toilet in our TT. The tank is 26x62x7....3" drain and 1" vent. What fittings/grommets will we need for installation?

I'm not sure exactly how yours is set up, but the vent sounds a little small. I would have thought it would be 1-1/2". You would use ABS pipe to pipe it to the roof, staying away from any air intake. The 3" discharge would have the flanges and slide valve. I use the Valterra products for this. I would use 3" ABS piping to the drop, wherever that that is. You would have a hose adapter on the end of the 3" drop. I used a stainless steel clamp for the adapter on my camper so that if I ever have to remove the cover, I don't have to cut the pipe. You will need an adapter to a closet flange on top of the tank, however that is mounted to your floor. There is no way anyone will be able to tell you the fittings you will need without knowing the exact routing and situation that you have.

Remember to grade the 3" drain at more than 1/4" per foot. 1/4" per foot is code, but your trailer may not be level when you are dumping so go a little more grade to keep from having issues.