Coachmen Clipper Shower Drain Leak

[hpt84]

Please see the attached pictures. I don't know why, but the pictures are posted upside down. I was fixing something else and notice this leak. It is a very tiny drip from the union between the white pipe and the black elbow. Just right above the red/blue tubing. To me this looks like a threaded union. Is there a way to tighten this? It is in a tight space and I just want to see if there was an easy fix without having to remove the shower pan above it. It is such a small drip that I might just live with it for awhile.