Moved into a new place last year and thankfully haven't had any problems (until now). Found a small leak under the bathroom sink on our mainfloor. As this bathroom is hardly ever used it went unnoticed until now and only leaks if you let the water run a little bit (a quick wash of the hands produces almost no leak).
I took the J pipe to Home Depot and they were confused as to why it would be leaking, since the piece looks fine. He suggested some teflon tape which a tried after first reattaching the pipe to simply make sure it wasn't just loose. The tape hasn't worked, so hoping for another suggestion.
I will try taking it apart tonight and cleaning the threads (didn't try this yet) to see if that hopefully works. No visible damage to any of the pieces, but because I took the part off our builder won't come in to look at it (won't make that mistake again

).
I attached a picture - you can see where the leak is coming from (where the white tape is). Any suggestions would be appreciated.