Draining hot tub after boondocking? Grey water..

When I hosted for the Sawtooth Ranger District in central Idaho, I asked the LEO about dumping gray water. His response was that you could wash dishes in a pan, take that pan outside and dump it. If you wash those same dishes in the sink, drain that water into your holding tank, then the water become gray and must be disposed of into an approved septic/sewer. It is the holding tank that creates the need to dispose of the gray water into the septic/sewer.