Staying at Walmarts and such

That's the reason that dump valves and drains are on the street side,rather than the curb side. Its visible from the road side. and if you park over a curb drain on that side, then you have to exit the door into the street. I know it sounds bad, but if the dumps were on the curb side, there would be a lot of dirty curbs. And there are a lot that still just pull up to a dump station or curb drain, and just let it all fly. Big expensive rigs have remote electric valves, driver doesn't even have to get out. and usually doesn't!