Leak???

[navybanker]

We used the camper over the Easter weekend and it rained each day except for return trip home. It rained on the trip to the CG. Upon return to stick house and backing the camper into the parking space, noticed water dripping from rear where the fresh water tank drain is. I thought the drain valve was leaking but the only water in the tank was about a pint of the pink stuff. Opened the valve and pink stuff came out. The dripping water was not pink and was draining down above and along the drain valve. Pushed up on the black cover on the bottom of the camper around the drain valve and some water run out the edge. Checked inside on the carpets and walls and didn't feel or see any moisture. It rained again last night (not heavy) and checked this morning and no water underneath near the fresh water tank drain or under the black cover. Any ideas on what happened and what to check next?