Oh dear, the gray water police are patrolling. Gray water was routinely dumped into waterways and everywhere else for decades. Not without damage. Back when there were phosphates in soaps and detergents, it was a bad idea and that is why laws were passed and it became a no-no. Then phosphates were banned. SO now you have all these regulations and no phosphates.
Then I would point out that there are various grades of gray water. If you pour grease and lots of food particles down your drain, your gray water will indeed smell. If you clean everything off and keep food out of it and only use it for washing your hands or a sponge bath, there isn't much damge going to be dobne to the environment. A little beach (which is a cousin to salt) won't hurt a bit.
I say dump away.