I have a 13' Casita (Patriot I think?) that does not have a grey water tank. Instead, there is an yellow, plastic, elbow-shaped outlet valve directly under the shower drain at the front of the trailer, closest to the tongue. In theory, the grey water is supposed to spill out directly under the trailer into the ground.
The gentleman we bought it from stated that he always attached a regular hose to this outlet valve so that the water would drain out somewhere other than right in your campsite. However, every time we shower there is a big wet spot on the interior of the trailer directly in front of the shower door. My theory is that either the hose is not draining fast enough and should not be on there in the first place, or there is some greater problem. Unfortunately, the manual has nothing to say on the subject. Does anyone have any insight into this problem?