Minor water leak

[Zia]

In my 2007 20ft Safari I found trace of water on the back side of the sink wall near the floor. I was able to see the moisture by removing the wood cover from the dinette seat and look through a cut out to the sink back wall. The amount of moisture indicate that it may not be in pressurized water line most probably on drainage side.
No water in the sink closet. Could it be due to condensation?
Any suggestion please

[Davis]

See if there may be condensation on the wall dripping onto the floor. Just a thought.