My 2001 ls430 has a water leak, it first showed up in the l/h rear floor board. Now, it appears to be showing its self not in the floor board but behind the lh rear seat.
I have a moon roof. Could this be a stopped up drain, if it is, ideas on unstopping it.

 

Sounds like it may be a clogged drain line for the roof. There are a couple threads discussing this very problem including photos and diagrams.

Even an active one that was just recently commented on.

https://www.clublexus.com/forums/ls-...-pictures.html

 

Take your drip rails of and clean those out and check the link 2k gave you should resolve your problem.