Attn Pop-up TC overlanders: gray water reinforced saddlebag?

We use a Swiss 5 Gallon water bag ($10) for our grey water. Love it. It's durable as all get out and has built in carry handles/rope.

We use it only while traveling so we just put a hose down into the fill port. DH just uses a bungee to hold it up from one of the stake pockets and it fits between the camper and truck bed. The few gallons we use doesn't slosh out and we empty it as soon as we stop.

Google it and see what I mean.