2" gray water drain fitting...

The trailer outlet is a standard 1-1/2" NPT connection. The big box home improvement stores will have threaded fittings. I've decided that the garden hose adapter is somewhat worthless since it is unvented and restricts the flow to nearly nothing.

I use a black ABS plastic fittings to a assemble a very functional system. I start with a female treaded fitting on the trailer to a wye fitting. From the lower side of the wye, I have a 45-degree elbow to a 1-1/2" pipe, 24" long. This goes into my gray water collection bucket (or a 1-1/2" to 3" adapter and stinky-slinky for full hookup sites). From the top side of the wye I have another 24" long pipe going vertical to vent. The vent makes a major difference in the drain operation. Since it is an unpressurized gravity drain, the entire set up is just slid together so I can easily assemble/disassemble.

I was able to get the fitting to screw on at Home Depot. I then put an elbow, and a piece of pool vacuum hose.

Thanks to all who replied; I've ordered the part!
Gary

The gray water fitting on pup's is pretty much standard. Mine measures 1 7/8" OD and 1 1/2" ID.

That should be the proper fitting. I've got 2 for our Coleman gray water drains. Another option is to take a 3" bayonet cap, cut a hole in the middle and use a PVC threaded to slip adapter. Screw the adapter on and it will hold the cap in place. Then a traditional sewer hose can be connected. I do this to connect a gray water tote to the sink drain. We drain the shower into a bucket and use it to douse the camp fire

That fitting looks right; I measured 2" OD, maybe their 1.5" measurement is ID?

My gray water outlet uses one of these.

http://www.amazon.com/gp/product/B0006MTREC?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00

It would be hard to describe the fittings you would need. I would go where they sell plastic pipe and tell them what you want to do. They can easily fix you up, to adapt to a water hose for a drain line.