Do I need a grey water tank?

[JCrown]

We just bought a 79 Mesa that had a sink but no plumbing. I am almost done with the plumbing, just waiting on my fresh water tank. I plumbed the drain back to the original drain outlet which just comes out behind the driver side tire. I have been tent camping all of my life but this is our first camper so I am not sure of the rules on gray water. Do we have to put a gray water tank under the drain to catch the water or is it ok to just let it flow out onto the ground? We won't be sending any chemicals down it just water and dawn dish soap which I figured was fine cause they use that stuff to clean ducks that were in oil spills It doesn't seem like a problem to me but I don't want to negatively impact the environment.

[homer]

When we had ours we put a 5 gal.plastic bucket with lid and spout outside under the output line. Just stuck the drain line down the spout and when nearly full carried it off and flushed down campground toilet. Never had any issues with that.

[windetch]

Depends on the campground, most of them heavily frown on, if not outright ban, dumping greywater on the ground -- especially if there's any food waste in it. 
tbh when I tent camped I just washed stuff at the spigot, but I think they're getting stricter on that as well. 
Most of the RV campgrounds will have a dump station you can use. 

I picked up a 16gal portable tote for my Roamer, works great.

Started out with a 6gal, it filled up quick (with 5 people) and without wheels it was a little cumbersome to deal with. 

[JCrown]

I think I will get one of the totes with wheels. Those look like the easiest solution. Thanks for the replies and pics.

[Pony Power]

I use a 10-gallon blue wastewater portable tank. They are not too expensive and you will be legal wherever you camp.

[count me in]

I have taken the sinks out of my campers, and they aren't going back in, we camp where there is a shower house, problem solved