You could now tell that fella that for years a stock crate has to have a holding tank and if it sloshes onto the carriageway, big fines, washing out the crate in the wrong spot also makes folk nasty, especially farmers with the spread of bugs.............. but then he wouldn't care either, might have been the same fella I saw doing the washing and it was just draining straight down so his rig had a lake under it, he didn't care, the lake with suds was still there when he left the next morning.......
I really do like the simple solenoid set up, fit and forget, it would need a deadman switch otherwise I would forget to turn it off then wonder where all this damn water is coming from when I refill the tank, I'm deaf so a buzzer wouldn't be any good, probably have to be at least 20mm or it would take a month of sundays to drain.....