3 or 2 tanks?

[turf]

yes, you can turn that 45 elbow to the up position and fill that waste tank right back up with rinse water to get a thorough cleaning of the tank. then turn it down and let the tank drain away again. the worst is if the sewer end isnt secured to the hole and blows out when you dump. then you break out the hose and spray it all into the hole. dump stations are contoured to be self cleaning usually.