We seldom have to use a dump station. Last time was at the factory, in middle,of afternoon. One other guy there. A jerk came there and expected us to get out, of his way so he could dump.
That's one reason we choose the time. Not one other soul was there or came afterwards It takes a bit when the water flow is low and the tanks reasonably large. We ignored him long enough to get the black tank drained but not flushed. He sat on his horn. I don't know what he did since we left and went back and parked. Later , at the old factory service area he was popping his gum, nose in the air, talking about all his money.
MHs of today are not designed, it seems, for just pulling up and draining the combined gray black tank, of older trailers. Flushing does take a bit sometimes. I didn't time it but at RV sites it usually takes several minutes, already connected to sewer and water. If you have several larger rigs, in front, of you expect to take a bit. Campground Owners should take into consideration the time it takes and have more than one or sometimes two dumping connections and low water flow. If they can fill the waste tanks at their site it would save time. Dry camping well... All they would have to do is connect the sewer hose and flush water hose and pull one valve and the next. Hard to go at race speed though. Perhaps Robin Williams could host some competitive drain and flush competitions. :)