tooldad1041, in every State I've been in there are laws about disposing of greywater. I've been in some areas that encouraged it to be spread on the dusty gravel roads, but even the they were clear no to dump near a stream. Please don't. Greywater sounds better then black water but it's still not safe to dump into any stream. Please collect it and transport to the proper disposal (sewer) system.
Interesting... Never heard of this being done before... I think I want to live upstream!
2017 Coleman 300tq by Dutchman Toy Hauler. 34.5 feet long and under 10k Gross. 500 watt Solar 2000 watt Inverter, 1999 Ford F250 2WD 7.3 4R100 DP Tuner, S&B Cold Air Intake, Gauges, 6.0 Trans Cooler, Air Bags.
is the sink against the outside wall? If so run it through the side. Stub out a MPT fitting and screw on a cap, then make whatever adapter you need to drain it to a drywell or something OTHER THAN THE CREEK!
I know I am going to get toasted for this....but, however you plumb it, please don't run it, "into the creek." (see how polite I was, I said, "Please.")